[Do Not Merge] Release 1.12 (#10292)
* Update docs for fields allowed at root of CRD schema (#9973) * add plugin docs and examples (#10053) * docs update to promote TaintNodesByCondition to beta (#9626) * HPA Specificity Improvements (#8757) Updated the HPA docs to reference the `autoscaling/v2beta2` API version, and added documentation about the new fields. * adjust docs for pod ready++ (#10049) * Remove --cadvisor-port - has been deprecated since v1.10 (#10023) Change-Id: Id2a685473a243aef492a98ff450759f39e362557 * Add Documentation for Snapshot Feature (#9948) * Add documentation for snapshot feature * Update volume-snapshots.md * Add dry-run to api-concepts (#10033) * kubeadm-init: Update the offline support section (#10062) The update includes the following things (in mind with Kubernetes 1.12): - Remove the 1.8 image versions - Add the 1.10 image versions that were missing until now - Include a comment for the missing arch suffixes in 1.12 Signed-off-by: Rostislav M. Georgiev <rostislavg@vmware.com> * Say bye to `DynamicProvisioningScheduling` (#10157) The mentioned feature gate is now collapsed into `VolumeScheduling`. xref: kubernetes/kubernetes#67432 * Update ResourceQuota per PriorityClass state for 1.12 (#10229) * TokenRequest and TokenRequestProjection now beta (#10161) xref: kubernetes/kubernetes#67349 * Change feature state for kms provider to beta. (#10230) KMS Provider will be graduating to beta in v1.12, reflecting this change on the website. * coredns default (#10200) * Promote ShareProcessNamespace to beta in docs (#9996) * Add CoreDNS details to DNS Debug docs (#10201) * add coredns details * address nits, add query logging section * Update docs with topology aware dynamic provisioning (#9939) * Document topology aware volume binding feature * update for readability * Update storage-classes.md * comma splice * don't abbreviate * HPA Algorithm Information Improvements (#9780) * Update HPA docs with more algorithm details The HPA docs pointed to an out-of-date document for information on the algorithm details, which users were finding confusing. This sticks a section on the algorithm in the HPA docs instead, documenting both general behavior and corner cases. * Add glossary info, HPA docs on quantities People often ask about the quantity notation when working with the metrics APIs, so this adds a glossary entry on quantities (since they're used elsewhere in the system), and a short explantation in the HPA walkthough. * Information about HPA readiness and stabilization This adds information about the new changes to HPA readiness and stabilization from kubernetes/features#591, and other minor changes that landed in Kubernetes 1.12. * Update horizontal-pod-autoscale.md * Audit 1.12 doc (#9953) * audit 1.12 document * remove legacy audit feature https://github.com/kubernetes/kubernetes/pull/65862 * update feature gate doc * MountPropagation is now GA (#10090) * RuntimeClass documentation (#10102) * RuntimeClass documentation * Update runtime-class.md * Add documentation for Scheduler performance tuning (#10048) * Add documentation for Scheduler performance tuning * Update scheduler-perf-tuning.md * TTL controller for cleaning up finished resources (#10064) * TTL controller for cleaning up finished resources * Address comments * Update ttlafterfinished.md * Bump quota configuration api version (#10217) * Incremental update from master (#10278) * fix invalid href of cloud controller manager (#10240) * fix invalid yaml format (#10238) * update storage-limits doc with Azure disk part (#10224) update storage-limits doc with Azure disk part fix comments * Update kubelet-config-file.md (#10222) Update link to KubeletConfiguration struct. * fix a trivial misspelling (#10244) * Fix cassandra-statefulset.yaml indent level (#10243) * Mention minimum etcd versions (#10208) Source: https://groups.google.com/d/msg/kubernetes-dev/jMPA4JzKiY4/HIx2ugvLBAAJ * fix 404 error (#10250) * Small verb tweak (#10190) Present participle, ftw. * Add AnchorJS logic for header links (#10155) * Add AnchorJS JavaScript * Remove existing inpage_heading logic * Remove underline from anchor tags * Use single icon and add touch visibility * Use paragraph link icon for AnchorJS * Update Sass to use code formatting in docsContent headers * Update header size coverage to H3-H6 * fix broken link in kubefed.md (#10254) * Update the version numbers for the X-Remote-Extra- and Impersonate-Extra- key fixes (#9827) The fix was cherry picked into 1.11.3, 1.10.7, and 1.9.11: https://github.com/kubernetes/kubernetes/pull/67162 https://github.com/kubernetes/kubernetes/pull/67163 https://github.com/kubernetes/kubernetes/pull/67164 * fix typo (#10168) * fix typo * addressing comments. * Update setup-ha-etcd-with-kubeadm.md * fix typos (#10252) * fix description of contribute guide (#10253) * describe truncate feature about advanced audit (#10236) * describe truncate feature about advanced audit * Update audit.md * docs update to promote ScheduleDaemonSetPods to beta (#9923) * Dynamic volume limit updates for 1.12 (#10211) * add a placeholder commit * Update docs for csi volume limits * Update storage-limits.md * Add "MayRunAs" value among other GroupStrategies (#9888) * Add CoreDNS details to the customize DNS doc (#10228) * Add CoreDNS details to the customize DNS doc Rewrite the document to include more details about CoreDNS, since it's now the default from v1.12 * Address comments * Improve doc wording * Fix link * Update dns-custom-nameservers.md * Update dns-custom-nameservers.md * Fix secrets docs in 1.12 branch (#10056) * Fix secrets docs * Update secret.md * Revert CoreDNS Docs (#10319) * Revert "Add CoreDNS details to DNS Debug docs (#10201)" This reverts commit462817a674. * Revert "Add CoreDNS details to the customize DNS doc (#10228)" This reverts commite7319eeb8c. * Revert "coredns default (#10200)" This reverts commit698e93b441. * Add CRI installation instructions page Added cri-installation page with CRI installation instructions Referenced it from kubeadm-init and install-kubeadm pages. * kubeadm: update API types documentation for 1.12 (#10283) v1alpha2 -> v1alpha3 MasterConfiguration -> [new-api-types] * TokenRequest feature documentation (#10295) * AdvancedAuditing is now GA (#10156) xref: kubernetes/kubernetes#65862 `AdvancedAuditing` feature is GA in 1.12. This PR adjusts the related docs. * update runtime-class.md (#10332) * update runtime-class.md * Update runtime-class.md * Document cross-authorizer permissions for creating RBAC roles (#10015) * Document cross-authorizer permissions for creating RBAC roles * Update rbac.md * kubeadm: update authored content for 1.12 (reference docs and cluster creation) (#10348) * kubeadm: update authored content in reference docs for 1.12 * kubeadm: add time frame in create-cluster-kubeadm for 1.12 * add AllowedProcMountTypes and ProcMountType to docs (#9911) Signed-off-by: Jess Frazelle <acidburn@microsoft.com> * kubeadm: add new command line reference (#10306) Add: - placeholder files - include place holder files - include "renew" sub command - add missing tabs for "alpha phase kubelet" * Documenting SCTP support in Kubernetes (#10279) * Documenting SCTP support in Kubernetes Service, Endpoint, NetworkPolicy and Pod * Updates based on comments on the PR * kubectl expose update with SCTP support * Updated according to comments in the PR * Revert "kubectl expose update with SCTP support" This reverts commit 0d5a1e6720a012390cf100c83e16b4a8c0782356. * TLS Bootstrap and Server Cert Rotation feature documentation (#10232) * TokenRequest feature documentation * line wrapping to make review not insane * update content for GA without major refactor * Update kubelet-tls-bootstrapping.md * Add clarifications for volume snapshots (#10296) * Update kubadm ha installation for 1.12 (#10264) * Update kubadm ha installation for 1.12 Signed-off-by: Chuck Ha <ha.chuck@gmail.com> * update stable version Signed-off-by: Chuck Ha <ha.chuck@gmail.com> * Update stacked control plane for v1.12 (#2) * use v1alpha3 Signed-off-by: Chuck Ha <ha.chuck@gmail.com> * more v1alpha3 (#4) * updates Signed-off-by: Chuck Ha <ha.chuck@gmail.com> * Document how to run in-tree cloud providers with kubeadm (#10357) Change-Id: Iab6b996a830503d74a6eb0c507c5f8ca7a39235b * kubeadm reference doc for release 1.12 (#10359) * Revert "Revert "Add CoreDNS details to DNS Debug docs (#10201)"" This reverts commit bb30f4d1fcd6fba2fe6190778ead99f8010033b7. * Revert "Revert "Add CoreDNS details to the customize DNS doc (#10228)"" This reverts commit bc23d45c09d7b83cac130fe22a0bd91e72435862. * Revert "Revert "coredns default (#10200)"" This reverts commit 7f4350d6ab7fc554ee53126d3875e845d2e43d1f. * add missing instruction for ha guide (#10374) Signed-off-by: Chuck Ha <ha.chuck@gmail.com> * kubeadm - Ha upgrade updates (#10340) * Update HA upgrade docs * Adds external etcd HA upgrade guide Signed-off-by: Chuck Ha <ha.chuck@gmail.com> * copyedit * more edits * add runasgroup in psp (#10076) * update KubeletPluginsWatcher feature gate (#10205) * generated 1.12 docs * Building Multi-arch images with Manifests (#10379) In 1.12, a variety of images used in a typical kubernetes installation have started to using manifests to better support environments with arm or ppc64le architectures. For example all images used with kubeadm by default have manifests, another would be all the tests in the conformance test suite. Here we capture the best practices for everyone to start using manifests in their own workflows. Change-Id: I5ba4c5fe55ffc9486a8251760f3352be4f2e1494 * Upgrade docs for v1.12 (#10344) * generated assets and docs * remove 1.7 * update 1.12 * update plugin documentation under docs>tasks>extend-kubectl (#10259) * update plugin documentation under docs>tasks>extend-kubectl * Update kubectl-plugins.md
This commit is contained in:
Jim Angel
+24
-2
@@ -447,8 +447,9 @@ The column's `format` controls the style used when `kubectl` prints the value.
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### Subresources
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{{< feature-state state="beta" for_kubernetes_version="1.11" >}}
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Custom resources support `/status` and `/scale` subresources.
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This feature is __beta__ in v1.11 and enabled by default.
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You can disable this feature using the `CustomResourceSubresources` feature gate on
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the [kube-apiserver](/docs/admin/kube-apiserver):
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@@ -469,7 +470,28 @@ When the status subresource is enabled, the `/status` subresource for the custom
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- `PUT` requests to the `/status` subresource only validate the status stanza of the custom resource.
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- `PUT`/`POST`/`PATCH` requests to the custom resource ignore changes to the status stanza.
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- Any changes to the spec stanza increments the value at `.metadata.generation`.
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- `properties`, `required` and `description` are the only constructs allowed in the root of the CRD OpenAPI validation schema.
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- Only the following constructs are allowed at the root of the CRD OpenAPI validation schema:
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- Description
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- Example
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- ExclusiveMaximum
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- ExclusiveMinimum
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- ExternalDocs
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- Format
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- Items
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- Maximum
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- MaxItems
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- MaxLength
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- Minimum
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- MinItems
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- MinLength
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- MultipleOf
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- Pattern
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- Properties
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- Required
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- Title
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- Type
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- UniqueItems
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#### Scale subresource
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@@ -28,28 +28,19 @@ DNS is a built-in Kubernetes service launched automatically
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using the addon manager
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[cluster add-on](http://releases.k8s.io/{{< param "githubbranch" >}}/cluster/addons/README.md).
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The running DNS Pod holds 3 containers:
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As of Kubernetes v1.12, CoreDNS is the recommended DNS Server, replacing kube-dns. However, kube-dns may still be installed by
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default with certain Kubernetes installer tools. Refer to the documentation provided by your installer to know which DNS server is installed by default.
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- "`kubedns`": watches the Kubernetes master for changes
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in Services and Endpoints, and maintains in-memory lookup structures to serve
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DNS requests.
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- "`dnsmasq`": adds DNS caching to improve performance.
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- "`sidecar`": provides a single health check endpoint
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to perform healthchecks for `dnsmasq` and `kubedns`.
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The DNS Pod is exposed as a Kubernetes Service with a static IP.
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The kubelet passes DNS to each container with the `--cluster-dns=<dns-service-ip>`
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flag.
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The CoreDNS Deployment is exposed as a Kubernetes Service with a static IP.
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Both the CoreDNS and kube-dns Service are named `kube-dns` in the `metadata.name` field. This is done so that there is greater interoperability with workloads that relied on the legacy `kube-dns` Service name to resolve addresses internal to the cluster. It abstracts away the implementation detail of which DNS provider is running behind that common endpoint.
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The kubelet passes DNS to each container with the `--cluster-dns=<dns-service-ip>` flag.
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DNS names also need domains. You configure the local domain in the kubelet
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with the flag `--cluster-domain=<default-local-domain>`.
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The Kubernetes cluster DNS server is based on the
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[SkyDNS](https://github.com/skynetservices/skydns) library. It supports forward
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lookups (A records), service lookups (SRV records), and reverse IP address
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lookups (PTR records).
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## Inheriting DNS from the node
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The DNS server supports forward lookups (A records), port lookups (SRV records), reverse IP address lookups (PTR records),
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and more. For more information see [DNS for Services and Pods] (/docs/concepts/services-networking/dns-pod-service/).
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If a Pod's `dnsPolicy` is set to "`default`", it inherits the name resolution
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configuration from the node that the Pod runs on. The Pod's DNS resolution
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@@ -61,7 +52,130 @@ use the kubelet's `--resolv-conf` flag. Set this flag to "" to prevent Pods fro
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inheriting DNS. Set it to a valid file path to specify a file other than
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`/etc/resolv.conf` for DNS inheritance.
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## Configure stub-domain and upstream DNS servers
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## CoreDNS
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CoreDNS is a general-purpose authoritative DNS server that can serve as cluster DNS, complying with the [dns specifications]
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(https://github.com/kubernetes/dns/blob/master/docs/specification.md).
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### CoreDNS ConfigMap options
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CoreDNS is a DNS server that is modular and pluggable, and each plugin adds new functionality to CoreDNS.
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This can be configured by maintaining a [Corefile](https://coredns.io/2017/07/23/corefile-explained/), which is the CoreDNS
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configuration file. A cluster administrator can modify the ConfigMap for the CoreDNS Corefile to change how service discovery works.
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In Kubernetes, CoreDNS is installed with the following default Corefile configuration.
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```yaml
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apiVersion: v1
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kind: ConfigMap
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metadata:
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name: coredns
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namespace: kube-system
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Corefile: |
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.:53 {
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errors
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health
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kubernetes cluster.local in-addr.arpa ip6.arpa {
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pods insecure
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upstream
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fallthrough in-addr.arpa ip6.arpa
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}
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prometheus :9153
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proxy . /etc/resolv.conf
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cache 30
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loop
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reload
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loadbalance
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}
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```
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The Corefile configuration includes the following [plugins](https://coredns.io/plugins/) of CoreDNS:
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* [errors](https://coredns.io/plugins/errors/): Errors are logged to stdout.
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* [health](https://coredns.io/plugins/health/): Health of CoreDNS is reported to http://localhost:8080/health.
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* [kubernetes](https://coredns.io/plugins/kubernetes/): CoreDNS will reply to DNS queries based on IP of the services and pods of Kubernetes. You can find more details [here](https://coredns.io/plugins/kubernetes/).
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> The `pods insecure` option is provided for backward compatibility with kube-dns. You can use the `pod verified` option, which returns an A record only if there exists a pod in same namespace with matching IP. The `pods disabled` option can be used if you don't use pod records.
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> `Upstream` is used for resolving services that point to external hosts (External Services).
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* [prometheus](https://coredns.io/plugins/prometheus/): Metrics of CoreDNS are available at http://localhost:9153/metrics in [Prometheus](https://prometheus.io/) format.
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* [proxy](https://coredns.io/plugins/proxy/): Any queries that are not within the cluster domain of Kubernetes will be forwarded to predefined resolvers (/etc/resolv.conf).
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* [cache](https://coredns.io/plugins/cache/): This enables a frontend cache.
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* [loop](https://coredns.io/plugins/loop/): Detects simple forwarding loops and halts the CoreDNS process if a loop is found.
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* [reload](https://coredns.io/plugins/reload): Allows automatic reload of a changed Corefile.
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* [loadbalance](https://coredns.io/plugins/loadbalance): This is a round-robin DNS loadbalancer by randomizing the order of A, AAAA, and MX records in the answer.
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We can modify the default behavior by modifying this configmap.
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### Configuration of Stub-domain and upstream nameserver using CoreDNS
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CoreDNS has the ability to configure stubdomains and upstream nameservers using the [proxy plugin](https://coredns.io/plugins/proxy/).
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#### Example
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If a cluster operator has a [Consul](https://www.consul.io/) domain server located at 10.150.0.1, and all Consul names have the suffix .consul.local. To configure it in CoreDNS, the cluster administrator creates the following stanza in the CoreDNS ConfigMap.
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```
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consul.local:53 {
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errors
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cache 30
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proxy . 10.150.0.1
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}
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```
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To explicitly force all non-cluster DNS lookups to go through a specific nameserver at 172.16.0.1, point the `proxy` and `upstream` to the nameserver instead of `/etc/resolv.conf`
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```
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proxy . 172.16.0.1
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```
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```
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upstream 172.16.0.1
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```
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So, the final ConfigMap along with the default `Corefile` configuration will look like:
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```yaml
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apiVersion: v1
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kind: ConfigMap
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metadata:
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name: coredns
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namespace: kube-system
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Corefile: |
|
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.:53 {
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errors
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health
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kubernetes cluster.local in-addr.arpa ip6.arpa {
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pods insecure
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upstream 172.16.0.1
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fallthrough in-addr.arpa ip6.arpa
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}
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prometheus :9153
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proxy . 172.16.0.1
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cache 30
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loop
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reload
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loadbalance
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}
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consul.local:53 {
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errors
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cache 30
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proxy . 10.150.0.1
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}
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```
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In Kubernetes version 1.10 and later, kubeadm supports automatic translation of the CoreDNS ConfigMap from the kube-dns ConfigMap.
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## Kube-dns
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Kube-dns is now available as a optional DNS server since CoreDNS is now the default.
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The running DNS Pod holds 3 containers:
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|
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- "`kubedns`": watches the Kubernetes master for changes
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in Services and Endpoints, and maintains in-memory lookup structures to serve
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DNS requests.
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- "`dnsmasq`": adds DNS caching to improve performance.
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- "`sidecar`": provides a single health check endpoint
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to perform healthchecks for `dnsmasq` and `kubedns`.
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### Configure stub-domain and upstream DNS servers
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Cluster administrators can specify custom stub domains and upstream nameservers
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by providing a ConfigMap for kube-dns (`kube-system:kube-dns`).
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@@ -102,7 +216,7 @@ details about the configuration option format.
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{{% capture discussion %}}
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### Effects on Pods
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#### Effects on Pods
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Custom upstream nameservers and stub domains do not affect Pods with a
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`dnsPolicy` set to "`Default`" or "`None`".
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@@ -136,7 +250,7 @@ DNS queries are routed according to the following flow:
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## ConfigMap options
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### ConfigMap options
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Options for the kube-dns `kube-system:kube-dns` ConfigMap:
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@@ -145,9 +259,9 @@ Options for the kube-dns `kube-system:kube-dns` ConfigMap:
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| `stubDomains` (optional) | A JSON map using a DNS suffix key such as “acme.local”, and a value consisting of a JSON array of DNS IPs. | The target nameserver can itself be a Kubernetes Service. For instance, you can run your own copy of dnsmasq to export custom DNS names into the ClusterDNS namespace. |
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| `upstreamNameservers` (optional) | A JSON array of DNS IPs. | If specified, the values replace the nameservers taken by default from the node’s `/etc/resolv.conf`. Limits: a maximum of three upstream nameservers can be specified. |
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### Examples
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||||
#### Examples
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||||
|
||||
#### Example: Stub domain
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##### Example: Stub domain
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||||
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In this example, the user has a Consul DNS service discovery system they want to
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||||
integrate with kube-dns. The consul domain server is located at 10.150.0.1, and
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||||
@@ -169,7 +283,7 @@ Note that the cluster administrator does not want to override the node’s
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upstream nameservers, so they did not specify the optional
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`upstreamNameservers` field.
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||||
|
||||
#### Example: Upstream nameserver
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||||
##### Example: Upstream nameserver
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||||
|
||||
In this example the cluster administrator wants to explicitly force all
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non-cluster DNS lookups to go through their own nameserver at 172.16.0.1.
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@@ -189,17 +303,9 @@ data:
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|
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{{% /capture %}}
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|
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## Configuring CoreDNS {#config-coredns}
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## CoreDNS configuration equivalent to kube-dns
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You can configure [CoreDNS](https://coredns.io/) as a service discovery.
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|
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CoreDNS is available as an option in Kubernetes starting with version 1.9.
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It is currently a [GA feature](https://github.com/kubernetes/community/blob/master/keps/sig-network/0010-20180314-coredns-GA-proposal.md) and is on course to be [the default](https://github.com/kubernetes/community/blob/master/keps/sig-network/0012-20180518-coredns-default-proposal.md), replacing kube-dns.
|
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|
||||
|
||||
## CoreDNS ConfigMap options
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||||
|
||||
CoreDNS chains plugins and can be configured by maintaining a Corefile with the ConfigMap. CoreDNS supports all the functionalities and more that is provided by kube-dns.
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CoreDNS supports all the functionalities and more that is provided by kube-dns.
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A ConfigMap created for kube-dns to support `StubDomains`and `upstreamNameservers` translates to the `proxy` plugin in CoreDNS.
|
||||
Similarly, the `Federation` plugin translates to the `federation` plugin in CoreDNS.
|
||||
|
||||
@@ -276,8 +382,8 @@ In Kubernetes version 1.10 and later, kubeadm supports automatic translation of
|
||||
|
||||
## Migration to CoreDNS
|
||||
|
||||
A number of tools support the installation of CoreDNS instead of kube-dns.
|
||||
To migrate from kube-dns to CoreDNS, [a detailed blog](https://coredns.io/2018/05/21/migration-from-kube-dns-to-coredns/) is available to help users adapt CoreDNS in place of kube-dns.
|
||||
A cluster administrator can also migrate using [the deploy script](https://github.com/coredns/deployment/blob/master/kubernetes/deploy.sh), which will also help you translate the kube-dns configmap to the equivalent CoreDNS one.
|
||||
|
||||
## What's next
|
||||
- [Debugging DNS Resolution](/docs/tasks/administer-cluster/dns-debugging-resolution/).
|
||||
|
||||
@@ -13,7 +13,7 @@ This page provides hints on diagnosing DNS problems.
|
||||
{{% capture prerequisites %}}
|
||||
* {{< include "task-tutorial-prereqs.md" >}} {{< version-check >}}
|
||||
* Kubernetes version 1.6 and above.
|
||||
* The cluster must be configured to use the `kube-dns` addon.
|
||||
* The cluster must be configured to use the `coredns` (or `kube-dns`) addons.
|
||||
{{% /capture %}}
|
||||
|
||||
{{% capture steps %}}
|
||||
@@ -68,7 +68,7 @@ nameserver 10.0.0.10
|
||||
options ndots:5
|
||||
```
|
||||
|
||||
Errors such as the following indicate a problem with the kube-dns add-on or
|
||||
Errors such as the following indicate a problem with the coredns/kube-dns add-on or
|
||||
associated Services:
|
||||
|
||||
```
|
||||
@@ -93,6 +93,17 @@ nslookup: can't resolve 'kubernetes.default'
|
||||
|
||||
Use the `kubectl get pods` command to verify that the DNS pod is running.
|
||||
|
||||
For CoreDNS:
|
||||
```shell
|
||||
kubectl get pods --namespace=kube-system -l k8s-app=kube-dns
|
||||
NAME READY STATUS RESTARTS AGE
|
||||
...
|
||||
coredns-7b96bf9f76-5hsxb 1/1 Running 0 1h
|
||||
coredns-7b96bf9f76-mvmmt 1/1 Running 0 1h
|
||||
...
|
||||
```
|
||||
|
||||
Or for kube-dns:
|
||||
```shell
|
||||
kubectl get pods --namespace=kube-system -l k8s-app=kube-dns
|
||||
NAME READY STATUS RESTARTS AGE
|
||||
@@ -107,8 +118,26 @@ have to deploy it manually.
|
||||
|
||||
### Check for Errors in the DNS pod
|
||||
|
||||
Use `kubectl logs` command to see logs for the DNS daemons.
|
||||
Use `kubectl logs` command to see logs for the DNS containers.
|
||||
|
||||
For CoreDNS:
|
||||
```shell
|
||||
for p in $(kubectl get pods --namespace=kube-system -l k8s-app=kube-dns -o name); do kubectl logs --namespace=kube-system $p; done
|
||||
```
|
||||
|
||||
Here is an example of a healthy CoreDNS log:
|
||||
|
||||
```
|
||||
.:53
|
||||
2018/08/15 14:37:17 [INFO] CoreDNS-1.2.2
|
||||
2018/08/15 14:37:17 [INFO] linux/amd64, go1.10.3, 2e322f6
|
||||
CoreDNS-1.2.2
|
||||
linux/amd64, go1.10.3, 2e322f6
|
||||
2018/08/15 14:37:17 [INFO] plugin/reload: Running configuration MD5 = 24e6c59e83ce706f07bcc82c31b1ea1c
|
||||
```
|
||||
|
||||
|
||||
For kube-dns, there are 3 sets of logs:
|
||||
```shell
|
||||
kubectl logs --namespace=kube-system $(kubectl get pods --namespace=kube-system -l k8s-app=kube-dns -o name | head -1) -c kubedns
|
||||
|
||||
@@ -117,8 +146,8 @@ kubectl logs --namespace=kube-system $(kubectl get pods --namespace=kube-system
|
||||
kubectl logs --namespace=kube-system $(kubectl get pods --namespace=kube-system -l k8s-app=kube-dns -o name | head -1) -c sidecar
|
||||
```
|
||||
|
||||
See if there is any suspicious log. Letter '`W`', '`E`', '`F`' at the beginning
|
||||
represent Warning, Error and Failure. Please search for entries that have these
|
||||
See if there are any suspicious error messages in the logs. In kube-dns, a '`W`', '`E`' or '`F`' at the beginning
|
||||
of a line represents a Warning, Error or Failure. Please search for entries that have these
|
||||
as the logging level and use
|
||||
[kubernetes issues](https://github.com/kubernetes/kubernetes/issues)
|
||||
to report unexpected errors.
|
||||
@@ -135,6 +164,8 @@ kube-dns ClusterIP 10.0.0.10 <none> 53/UDP,53/TCP 1h
|
||||
...
|
||||
```
|
||||
|
||||
|
||||
Note that the service name will be "kube-dns" for both CoreDNS and kube-dns deployments.
|
||||
If you have created the service or in the case it should be created by default
|
||||
but it does not appear, see
|
||||
[debugging services](/docs/tasks/debug-application-cluster/debug-service/) for
|
||||
@@ -158,20 +189,83 @@ For additional Kubernetes DNS examples, see the
|
||||
[cluster-dns examples](https://github.com/kubernetes/examples/tree/master/staging/cluster-dns)
|
||||
in the Kubernetes GitHub repository.
|
||||
|
||||
|
||||
### Are DNS queries being received/processed?
|
||||
|
||||
You can verify if queries are being received by CoreDNS by adding the `log` plugin to the CoreDNS configuration (aka Corefile).
|
||||
The CoreDNS Corefile is held in a ConfigMap named `coredns`. To edit it, use the command ...
|
||||
|
||||
```
|
||||
kubectl -n kube-system edit configmap coredns
|
||||
```
|
||||
|
||||
Then add `log` in the Corefile section per the example below.
|
||||
|
||||
```
|
||||
apiVersion: v1
|
||||
kind: ConfigMap
|
||||
metadata:
|
||||
name: coredns
|
||||
namespace: kube-system
|
||||
data:
|
||||
Corefile: |
|
||||
.:53 {
|
||||
log
|
||||
errors
|
||||
health
|
||||
kubernetes cluster.local in-addr.arpa ip6.arpa {
|
||||
pods insecure
|
||||
upstream
|
||||
fallthrough in-addr.arpa ip6.arpa
|
||||
}
|
||||
prometheus :9153
|
||||
proxy . /etc/resolv.conf
|
||||
cache 30
|
||||
loop
|
||||
reload
|
||||
loadbalance
|
||||
}
|
||||
|
||||
```
|
||||
|
||||
After saving the changes, it may take up to minute or two for Kubernetes to propagate these changes to the CoreDNS pods.
|
||||
|
||||
Next, make some queries and view the logs per the sections above in this document. If CoreDNS pods are receiving the queries, you should see them in the logs.
|
||||
|
||||
Here is an example of a query in the log.
|
||||
|
||||
```
|
||||
.:53
|
||||
2018/08/15 14:37:15 [INFO] CoreDNS-1.2.0
|
||||
2018/08/15 14:37:15 [INFO] linux/amd64, go1.10.3, 2e322f6
|
||||
CoreDNS-1.2.0
|
||||
linux/amd64, go1.10.3, 2e322f6
|
||||
2018/09/07 15:29:04 [INFO] plugin/reload: Running configuration MD5 = 162475cdf272d8aa601e6fe67a6ad42f
|
||||
2018/09/07 15:29:04 [INFO] Reloading complete
|
||||
172.17.0.18:41675 - [07/Sep/2018:15:29:11 +0000] 59925 "A IN kubernetes.default.svc.cluster.local. udp 54 false 512" NOERROR qr,aa,rd,ra 106 0.000066649s
|
||||
|
||||
```
|
||||
|
||||
## Known issues
|
||||
|
||||
Kubernetes installs do not configure the nodes' resolv.conf files to use the
|
||||
cluster DNS by default, because that process is inherently distro-specific.
|
||||
Some Linux distributions (e.g. Ubuntu), use a local DNS resolver by default (systemd-resolved).
|
||||
Systemd-resolved moves and replaces `/etc/resolv.conf` with a stub file that can cause a fatal forwarding
|
||||
loop when resolving names in upstream servers. This can be fixed manually by using kubelet's `--resolv-conf` flag
|
||||
to point to the correct `resolv.conf` (With `systemd-resolved`, this is `/run/systemd/resolve/resolv.conf`).
|
||||
kubeadm 1.11 automatically detects `systemd-resolved`, and adjusts the kubelet flags accordingly.
|
||||
|
||||
Kubernetes installs do not configure the nodes' `resolv.conf` files to use the
|
||||
cluster DNS by default, because that process is inherently distribution-specific.
|
||||
This should probably be implemented eventually.
|
||||
|
||||
Linux's libc is impossibly stuck ([see this bug from
|
||||
2005](https://bugzilla.redhat.com/show_bug.cgi?id=168253)) with limits of just
|
||||
3 DNS `nameserver` records and 6 DNS `search` records. Kubernetes needs to
|
||||
consume 1 `nameserver` record and 3 `search` records. This means that if a
|
||||
3 DNS `nameserver` records and 6 DNS `search` records. Kubernetes needs to
|
||||
consume 1 `nameserver` record and 3 `search` records. This means that if a
|
||||
local installation already uses 3 `nameserver`s or uses more than 3 `search`es,
|
||||
some of those settings will be lost. As a partial workaround, the node can run
|
||||
some of those settings will be lost. As a partial workaround, the node can run
|
||||
`dnsmasq` which will provide more `nameserver` entries, but not more `search`
|
||||
entries. You can also use kubelet's `--resolv-conf` flag.
|
||||
entries. You can also use kubelet's `--resolv-conf` flag.
|
||||
|
||||
If you are using Alpine version 3.3 or earlier as your base image, DNS may not
|
||||
work properly owing to a known issue with Alpine.
|
||||
|
||||
@@ -36,10 +36,10 @@ The output is similar to this:
|
||||
|
||||
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
|
||||
...
|
||||
kube-dns-autoscaler 1 1 1 1 ...
|
||||
dns-autoscaler 1 1 1 1 ...
|
||||
...
|
||||
|
||||
If you see "kube-dns-autoscaler" in the output, DNS horizontal autoscaling is
|
||||
If you see "dns-autoscaler" in the output, DNS horizontal autoscaling is
|
||||
already enabled, and you can skip to
|
||||
[Tuning autoscaling parameters](#tuning-autoscaling-parameters).
|
||||
|
||||
@@ -53,10 +53,13 @@ The output is similar to this:
|
||||
|
||||
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
|
||||
...
|
||||
kube-dns 1 1 1 1 ...
|
||||
coredns 2 2 2 2 ...
|
||||
...
|
||||
|
||||
In Kubernetes versions earlier than 1.5 DNS is implemented using a
|
||||
|
||||
In Kubernetes versions earlier than 1.12, the DNS Deployment was called "kube-dns".
|
||||
|
||||
In Kubernetes versions earlier than 1.5 DNS was implemented using a
|
||||
ReplicationController instead of a Deployment. So if you don't see kube-dns,
|
||||
or a similar name, in the preceding output, list the ReplicationControllers in
|
||||
your cluster in the kube-system namespace:
|
||||
@@ -77,7 +80,7 @@ If you have a DNS Deployment, your scale target is:
|
||||
Deployment/<your-deployment-name>
|
||||
|
||||
where <dns-deployment-name> is the name of your DNS Deployment. For example, if
|
||||
your DNS Deployment name is kube-dns, your scale target is Deployment/kube-dns.
|
||||
your DNS Deployment name is coredns, your scale target is Deployment/coredns.
|
||||
|
||||
If you have a DNS ReplicationController, your scale target is:
|
||||
|
||||
@@ -111,7 +114,7 @@ DNS horizontal autoscaling is now enabled.
|
||||
|
||||
## Tuning autoscaling parameters
|
||||
|
||||
Verify that the kube-dns-autoscaler ConfigMap exists:
|
||||
Verify that the dns-autoscaler ConfigMap exists:
|
||||
|
||||
kubectl get configmap --namespace=kube-system
|
||||
|
||||
@@ -119,12 +122,12 @@ The output is similar to this:
|
||||
|
||||
NAME DATA AGE
|
||||
...
|
||||
kube-dns-autoscaler 1 ...
|
||||
dns-autoscaler 1 ...
|
||||
...
|
||||
|
||||
Modify the data in the ConfigMap:
|
||||
|
||||
kubectl edit configmap kube-dns-autoscaler --namespace=kube-system
|
||||
kubectl edit configmap dns-autoscaler --namespace=kube-system
|
||||
|
||||
Look for this line:
|
||||
|
||||
@@ -151,15 +154,15 @@ There are other supported scaling patterns. For details, see
|
||||
There are a few options for turning DNS horizontal autoscaling. Which option to
|
||||
use depends on different conditions.
|
||||
|
||||
### Option 1: Scale down the kube-dns-autoscaler deployment to 0 replicas
|
||||
### Option 1: Scale down the dns-autoscaler deployment to 0 replicas
|
||||
|
||||
This option works for all situations. Enter this command:
|
||||
|
||||
kubectl scale deployment --replicas=0 kube-dns-autoscaler --namespace=kube-system
|
||||
kubectl scale deployment --replicas=0 dns-autoscaler --namespace=kube-system
|
||||
|
||||
The output is:
|
||||
|
||||
deployment.extensions/kube-dns-autoscaler scaled
|
||||
deployment.extensions/dns-autoscaler scaled
|
||||
|
||||
Verify that the replica count is zero:
|
||||
|
||||
@@ -169,33 +172,33 @@ The output displays 0 in the DESIRED and CURRENT columns:
|
||||
|
||||
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
|
||||
...
|
||||
kube-dns-autoscaler 0 0 0 0 ...
|
||||
dns-autoscaler 0 0 0 0 ...
|
||||
...
|
||||
|
||||
### Option 2: Delete the kube-dns-autoscaler deployment
|
||||
### Option 2: Delete the dns-autoscaler deployment
|
||||
|
||||
This option works if kube-dns-autoscaler is under your own control, which means
|
||||
This option works if dns-autoscaler is under your own control, which means
|
||||
no one will re-create it:
|
||||
|
||||
kubectl delete deployment kube-dns-autoscaler --namespace=kube-system
|
||||
kubectl delete deployment dns-autoscaler --namespace=kube-system
|
||||
|
||||
The output is:
|
||||
|
||||
deployment.extensions "kube-dns-autoscaler" deleted
|
||||
deployment.extensions "dns-autoscaler" deleted
|
||||
|
||||
### Option 3: Delete the kube-dns-autoscaler manifest file from the master node
|
||||
### Option 3: Delete the dns-autoscaler manifest file from the master node
|
||||
|
||||
This option works if kube-dns-autoscaler is under control of the
|
||||
This option works if dns-autoscaler is under control of the
|
||||
[Addon Manager](https://git.k8s.io/kubernetes/cluster/addons/README.md)'s
|
||||
control, and you have write access to the master node.
|
||||
|
||||
Sign in to the master node and delete the corresponding manifest file.
|
||||
The common path for this kube-dns-autoscaler is:
|
||||
The common path for this dns-autoscaler is:
|
||||
|
||||
/etc/kubernetes/addons/dns-horizontal-autoscaler/dns-horizontal-autoscaler.yaml
|
||||
|
||||
After the manifest file is deleted, the Addon Manager will delete the
|
||||
kube-dns-autoscaler Deployment.
|
||||
dns-autoscaler Deployment.
|
||||
|
||||
{{% /capture %}}
|
||||
|
||||
|
||||
@@ -16,7 +16,7 @@ This page shows how to configure a Key Management Service (KMS) provider and plu
|
||||
|
||||
* etcd v3 or later is required
|
||||
|
||||
{{< feature-state for_k8s_version="v1.10" state="alpha" >}}
|
||||
{{< feature-state for_k8s_version="v1.12" state="beta" >}}
|
||||
|
||||
{{% /capture %}}
|
||||
|
||||
|
||||
@@ -0,0 +1,295 @@
|
||||
---
|
||||
reviewers:
|
||||
- sig-cluster-lifecycle
|
||||
title: Upgrading kubeadm clusters from v1.11 to v1.12
|
||||
content_template: templates/task
|
||||
---
|
||||
|
||||
{{% capture overview %}}
|
||||
|
||||
This page explains how to upgrade a Kubernetes cluster created with `kubeadm` from version 1.11.x to version 1.12.x, and from version 1.12.x to 1.12.y, where `y > x`.
|
||||
|
||||
{{% /capture %}}
|
||||
|
||||
{{% capture prerequisites %}}
|
||||
|
||||
- You need to have a `kubeadm` Kubernetes cluster running version 1.11.0 or later.
|
||||
[Swap must be disabled][swap].
|
||||
The cluster should use a static control plane and etcd pods.
|
||||
- Make sure you read the [release notes](https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG-1.12.md) carefully.
|
||||
- Make sure to back up any important components, such as app-level state stored in a database.
|
||||
`kubeadm upgrade` does not touch your workloads, only components internal to Kubernetes, but backups are always a best practice.
|
||||
|
||||
|
||||
[swap]: https://serverfault.com/questions/684771/best-way-to-disable-swap-in-linux
|
||||
### Additional information
|
||||
|
||||
- All containers are restarted after upgrade, because the container spec hash value is changed.
|
||||
- You can upgrade only from one minor version to the next minor version.
|
||||
That is, you cannot skip versions when you upgrade.
|
||||
For example, you can upgrade only from 1.10 to 1.11, not from 1.9 to 1.11.
|
||||
|
||||
{{% /capture %}}
|
||||
|
||||
{{% capture steps %}}
|
||||
|
||||
## Upgrade the control plane
|
||||
|
||||
1. On your master node, upgrade kubeadm:
|
||||
|
||||
{{< tabs name="k8s_install" >}}
|
||||
{{% tab name="Ubuntu, Debian or HypriotOS" %}}
|
||||
apt-get update
|
||||
apt-get upgrade -y kubelet kubeadm
|
||||
{{% /tab %}}
|
||||
{{% tab name="CentOS, RHEL or Fedora" %}}
|
||||
yum upgrade -y kubeadm --disableexcludes=kubernetes
|
||||
{{% /tab %}}
|
||||
{{< /tabs >}}
|
||||
|
||||
1. Verify that the download works and has the expected version:
|
||||
|
||||
```shell
|
||||
kubeadm version
|
||||
```
|
||||
|
||||
1. On the master node, run:
|
||||
|
||||
```shell
|
||||
kubeadm upgrade plan
|
||||
```
|
||||
|
||||
You should see output similar to this:
|
||||
|
||||
```shell
|
||||
[preflight] Running pre-flight checks.
|
||||
[upgrade] Making sure the cluster is healthy:
|
||||
[upgrade/config] Making sure the configuration is correct:
|
||||
[upgrade/config] Reading configuration from the cluster...
|
||||
[upgrade/config] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
|
||||
[upgrade] Fetching available versions to upgrade to
|
||||
[upgrade/versions] Cluster version: v1.11.3
|
||||
[upgrade/versions] kubeadm version: v1.12.0
|
||||
[upgrade/versions] Latest stable version: v1.11.3
|
||||
[upgrade/versions] Latest version in the v1.11 series: v1.11.3
|
||||
[upgrade/versions] Latest experimental version: v1.13.0-alpha.0
|
||||
|
||||
Components that must be upgraded manually after you have upgraded the control plane with 'kubeadm upgrade apply':
|
||||
COMPONENT CURRENT AVAILABLE
|
||||
Kubelet 2 x v1.11.1 v1.12.0
|
||||
1 x v1.11.3 v1.12.0
|
||||
|
||||
Upgrade to the latest experimental version:
|
||||
|
||||
COMPONENT CURRENT AVAILABLE
|
||||
API Server v1.11.3 v1.12.0
|
||||
Controller Manager v1.11.3 v1.12.0
|
||||
Scheduler v1.11.3 v1.12.0
|
||||
Kube Proxy v1.11.3 v1.12.0
|
||||
CoreDNS 1.1.3 1.2.2
|
||||
Etcd 3.2.18 3.2.24
|
||||
|
||||
You can now apply the upgrade by executing the following command:
|
||||
|
||||
kubeadm upgrade apply v1.12.0
|
||||
|
||||
_____________________________________________________________________
|
||||
|
||||
```
|
||||
|
||||
This command checks that your cluster can be upgraded, and fetches the versions you can upgrade to.
|
||||
|
||||
1. Choose a version to upgrade to, and run the appropriate command. For example:
|
||||
|
||||
```shell
|
||||
kubeadm upgrade apply v1.12.0
|
||||
```
|
||||
|
||||
You should see output similar to this:
|
||||
|
||||
<!-- TODO: output from stable -->
|
||||
|
||||
```shell
|
||||
[preflight] Running pre-flight checks.
|
||||
[upgrade] Making sure the cluster is healthy:
|
||||
[upgrade/config] Making sure the configuration is correct:
|
||||
[upgrade/config] Reading configuration from the cluster...
|
||||
[upgrade/config] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
|
||||
[upgrade/apply] Respecting the --cri-socket flag that is set with higher priority than the config file.
|
||||
[upgrade/version] You have chosen to change the cluster version to "v1.12.0"
|
||||
[upgrade/versions] Cluster version: v1.11.3
|
||||
[upgrade/versions] kubeadm version: v1.12.0
|
||||
[upgrade/confirm] Are you sure you want to proceed with the upgrade? [y/N]: y
|
||||
[upgrade/prepull] Will prepull images for components [kube-apiserver kube-controller-manager kube-scheduler etcd]
|
||||
[upgrade/prepull] Prepulling image for component etcd.
|
||||
[upgrade/prepull] Prepulling image for component kube-apiserver.
|
||||
[upgrade/prepull] Prepulling image for component kube-controller-manager.
|
||||
[upgrade/prepull] Prepulling image for component kube-scheduler.
|
||||
[apiclient] Found 0 Pods for label selector k8s-app=upgrade-prepull-etcd
|
||||
[apiclient] Found 1 Pods for label selector k8s-app=upgrade-prepull-kube-apiserver
|
||||
[apiclient] Found 1 Pods for label selector k8s-app=upgrade-prepull-kube-scheduler
|
||||
[apiclient] Found 1 Pods for label selector k8s-app=upgrade-prepull-kube-controller-manager
|
||||
[apiclient] Found 1 Pods for label selector k8s-app=upgrade-prepull-etcd
|
||||
[upgrade/prepull] Prepulled image for component kube-apiserver.
|
||||
[upgrade/prepull] Prepulled image for component kube-controller-manager.
|
||||
[upgrade/prepull] Prepulled image for component kube-scheduler.
|
||||
[upgrade/prepull] Prepulled image for component etcd.
|
||||
[upgrade/prepull] Successfully prepulled the images for all the control plane components
|
||||
[upgrade/apply] Upgrading your Static Pod-hosted control plane to version "v1.12.0"...
|
||||
Static pod: kube-apiserver-ip-172-31-80-76 hash: d9b7af93990d702b3ee9a2beca93384b
|
||||
Static pod: kube-controller-manager-ip-172-31-80-76 hash: 44a081fb5d26e90773ceb98b4e16fe10
|
||||
Static pod: kube-scheduler-ip-172-31-80-76 hash: 009228e74aef4d7babd7968782118d5e
|
||||
Static pod: etcd-ip-172-31-80-76 hash: 997fcf3d8d974c98abc14556cc02617e
|
||||
[etcd] Wrote Static Pod manifest for a local etcd instance to "/etc/kubernetes/tmp/kubeadm-upgraded-manifests661777755/etcd.yaml"
|
||||
[upgrade/staticpods] Moved new manifest to "/etc/kubernetes/manifests/etcd.yaml" and backed up old manifest to "/etc/kubernetes/tmp/kubeadm-backup-manifests-2018-09-19-18-58-14/etcd.yaml"
|
||||
[upgrade/staticpods] Waiting for the kubelet to restart the component
|
||||
[upgrade/staticpods] This might take a minute or longer depending on the component/version gap (timeout 5m0s
|
||||
Static pod: etcd-ip-172-31-80-76 hash: 997fcf3d8d974c98abc14556cc02617e
|
||||
<snip>
|
||||
[apiclient] Found 1 Pods for label selector component=etcd
|
||||
[upgrade/staticpods] Component "etcd" upgraded successfully!
|
||||
[upgrade/etcd] Waiting for etcd to become available
|
||||
[util/etcd] Waiting 0s for initial delay
|
||||
[util/etcd] Attempting to see if all cluster endpoints are available 1/10
|
||||
[upgrade/staticpods] Writing new Static Pod manifests to "/etc/kubernetes/tmp/kubeadm-upgraded-manifests661777755"
|
||||
[controlplane] wrote Static Pod manifest for component kube-apiserver to "/etc/kubernetes/tmp/kubeadm-upgraded-manifests661777755/kube-apiserver.yaml"
|
||||
[controlplane] wrote Static Pod manifest for component kube-controller-manager to "/etc/kubernetes/tmp/kubeadm-upgraded-manifests661777755/kube-controller-manager.yaml"
|
||||
[controlplane] wrote Static Pod manifest for component kube-scheduler to "/etc/kubernetes/tmp/kubeadm-upgraded-manifests661777755/kube-scheduler.yaml"
|
||||
[upgrade/staticpods] Moved new manifest to "/etc/kubernetes/manifests/kube-apiserver.yaml" and backed up old manifest to "/etc/kubernetes/tmp/kubeadm-backup-manifests-2018-09-19-18-58-14/kube-apiserver.yaml"
|
||||
[upgrade/staticpods] Waiting for the kubelet to restart the component
|
||||
[upgrade/staticpods] This might take a minute or longer depending on the component/version gap (timeout 5m0s
|
||||
<snip>
|
||||
Static pod: kube-apiserver-ip-172-31-80-76 hash: 854a5a8468f899093c6a967bb81dcfbc
|
||||
[apiclient] Found 1 Pods for label selector component=kube-apiserver
|
||||
[upgrade/staticpods] Component "kube-apiserver" upgraded successfully!
|
||||
[upgrade/staticpods] Moved new manifest to "/etc/kubernetes/manifests/kube-controller-manager.yaml" and backed up old manifest to "/etc/kubernetes/tmp/kubeadm-backup-manifests-2018-09-19-18-58-14/kube-controller-manager.yaml"
|
||||
[upgrade/staticpods] Waiting for the kubelet to restart the component
|
||||
[upgrade/staticpods] This might take a minute or longer depending on the component/version gap (timeout 5m0s
|
||||
Static pod: kube-controller-manager-ip-172-31-80-76 hash: 44a081fb5d26e90773ceb98b4e16fe10
|
||||
Static pod: kube-controller-manager-ip-172-31-80-76 hash: b651f83474ae70031d5fb2cab73bd366
|
||||
[apiclient] Found 1 Pods for label selector component=kube-controller-manager
|
||||
[upgrade/staticpods] Component "kube-controller-manager" upgraded successfully!
|
||||
[upgrade/staticpods] Moved new manifest to "/etc/kubernetes/manifests/kube-scheduler.yaml" and backed up old manifest to "/etc/kubernetes/tmp/kubeadm-backup-manifests-2018-09-19-18-58-14/kube-scheduler.yaml"
|
||||
[upgrade/staticpods] Waiting for the kubelet to restart the component
|
||||
[upgrade/staticpods] This might take a minute or longer depending on the component/version gap (timeout 5m0s
|
||||
Static pod: kube-scheduler-ip-172-31-80-76 hash: 009228e74aef4d7babd7968782118d5e
|
||||
Static pod: kube-scheduler-ip-172-31-80-76 hash: da406e5a49adfbbeb90fe2a0cf8fd8d1
|
||||
[apiclient] Found 1 Pods for label selector component=kube-scheduler
|
||||
[upgrade/staticpods] Component "kube-scheduler" upgraded successfully!
|
||||
[uploadconfig] storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
|
||||
[kubelet] Creating a ConfigMap "kubelet-config-1.12" in namespace kube-system with the configuration for the kubelets in the cluster
|
||||
[kubelet] Downloading configuration for the kubelet from the "kubelet-config-1.12" ConfigMap in the kube-system namespace
|
||||
[kubelet] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
|
||||
[patchnode] Uploading the CRI Socket information "/var/run/dockershim.sock" to the Node API object "ip-172-31-80-76" as an annotation
|
||||
[bootstraptoken] configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
|
||||
[bootstraptoken] configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
|
||||
[bootstraptoken] configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
|
||||
[addons] Applied essential addon: CoreDNS
|
||||
[addons] Applied essential addon: kube-proxy
|
||||
|
||||
[upgrade/successful] SUCCESS! Your cluster was upgraded to "v1.12.0". Enjoy!
|
||||
|
||||
[upgrade/kubelet] Now that your control plane is upgraded, please proceed with upgrading your kubelets if you haven't already done so.
|
||||
```
|
||||
|
||||
1. Manually upgrade your Software Defined Network (SDN).
|
||||
|
||||
Your Container Network Interface (CNI) provider may have its own upgrade instructions to follow.
|
||||
Check the [addons](/docs/concepts/cluster-administration/addons/) page to
|
||||
find your CNI provider and see whether additional upgrade steps are required.
|
||||
|
||||
## Upgrade master and node packages
|
||||
|
||||
1. Prepare each node for maintenance, marking it unschedulable and evicting the workloads:
|
||||
|
||||
```shell
|
||||
kubectl drain $NODE --ignore-daemonsets
|
||||
```
|
||||
|
||||
On the master node, you must add `--ignore-daemonsets`:
|
||||
|
||||
```shell
|
||||
kubectl drain ip-172-31-85-18
|
||||
node "ip-172-31-85-18" cordoned
|
||||
error: unable to drain node "ip-172-31-85-18", aborting command...
|
||||
|
||||
There are pending nodes to be drained:
|
||||
ip-172-31-85-18
|
||||
error: DaemonSet-managed pods (use --ignore-daemonsets to ignore): calico-node-5798d, kube-proxy-thjp9
|
||||
```
|
||||
|
||||
```
|
||||
kubectl drain ip-172-31-85-18 --ignore-daemonsets
|
||||
node "ip-172-31-85-18" already cordoned
|
||||
WARNING: Ignoring DaemonSet-managed pods: calico-node-5798d, kube-proxy-thjp9
|
||||
node "ip-172-31-85-18" drained
|
||||
```
|
||||
|
||||
1. Upgrade the Kubernetes package version on each `$NODE` node by running the Linux package manager for your distribution:
|
||||
|
||||
{{< tabs name="k8s_install" >}}
|
||||
{{% tab name="Ubuntu, Debian or HypriotOS" %}}
|
||||
apt-get update
|
||||
apt-get upgrade -y kubelet kubeadm
|
||||
{{% /tab %}}
|
||||
{{% tab name="CentOS, RHEL or Fedora" %}}
|
||||
yum upgrade -y kubelet kubeadm --disableexcludes=kubernetes
|
||||
{{% /tab %}}
|
||||
{{< /tabs >}}
|
||||
|
||||
## Upgrade kubelet on each node
|
||||
|
||||
1. On each node except the master node, upgrade the kubelet config:
|
||||
|
||||
```shell
|
||||
sudo kubeadm upgrade node config --kubelet-version $(kubelet --version | cut -d ' ' -f 2)
|
||||
```
|
||||
|
||||
1. Restart the kubelet process:
|
||||
|
||||
```shell
|
||||
sudo systemctl restart kubelet
|
||||
```
|
||||
|
||||
1. Verify that the new version of the `kubelet` is running on the node:
|
||||
|
||||
```shell
|
||||
systemctl status kubelet
|
||||
```
|
||||
|
||||
1. Bring the node back online by marking it schedulable:
|
||||
|
||||
```shell
|
||||
kubectl uncordon $NODE
|
||||
```
|
||||
|
||||
1. After the kubelet is upgraded on all nodes, verify that all nodes are available again by running the following command from anywhere kubectl can access the cluster:
|
||||
|
||||
```shell
|
||||
kubectl get nodes
|
||||
```
|
||||
|
||||
The `STATUS` column should show `Ready` for all your nodes, and the version number should be updated.
|
||||
|
||||
{{% /capture %}}
|
||||
|
||||
## Recovering from a failure state
|
||||
|
||||
If `kubeadm upgrade` fails and does not roll back, for example because of an unexpected shutdown during execution, you can run `kubeadm upgrade` again.
|
||||
This command is idempotent and eventually makes sure that the actual state is the desired state you declare.
|
||||
|
||||
To recover from a bad state, you can also run `kubeadm upgrade --force` without changing the version that your cluster is running.
|
||||
|
||||
## How it works
|
||||
|
||||
`kubeadm upgrade apply` does the following:
|
||||
|
||||
- Checks that your cluster is in an upgradeable state:
|
||||
- The API server is reachable
|
||||
- All nodes are in the `Ready` state
|
||||
- The control plane is healthy
|
||||
- Enforces the version skew policies.
|
||||
- Makes sure the control plane images are available or available to pull to the machine.
|
||||
- Upgrades the control plane components or rollbacks if any of them fails to come up.
|
||||
- Applies the new `kube-dns` and `kube-proxy` manifests and enforces that all necessary RBAC rules are created.
|
||||
- Creates new certificate and key files of the API server and backs up old files if they're about to expire in 180 days.
|
||||
@@ -1,290 +0,0 @@
|
||||
---
|
||||
reviewers:
|
||||
- pipejakob
|
||||
- luxas
|
||||
- roberthbailey
|
||||
- jbeda
|
||||
title: Upgrading kubeadm clusters from 1.7 to 1.8
|
||||
content_template: templates/task
|
||||
---
|
||||
|
||||
{{% capture overview %}}
|
||||
|
||||
This guide is for upgrading `kubeadm` clusters from version 1.7.x to 1.8.x, as well as 1.7.x to 1.7.y and 1.8.x to 1.8.y where `y > x`.
|
||||
See also [upgrading kubeadm clusters from 1.6 to 1.7](/docs/tasks/administer-cluster/kubeadm-upgrade-1-7/) if you're on a 1.6 cluster currently.
|
||||
|
||||
{{% /capture %}}
|
||||
|
||||
{{% capture prerequisites %}}
|
||||
|
||||
Before proceeding:
|
||||
|
||||
- You need to have a functional `kubeadm` Kubernetes cluster running version 1.7.0 or higher in order to use the process described here.
|
||||
- Make sure you read the [release notes](https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG.md#v180-beta1) carefully.
|
||||
- As `kubeadm upgrade` does not upgrade etcd make sure to back it up. You can, for example, use `etcdctl backup` to take care of this.
|
||||
- Note that `kubeadm upgrade` will not touch any of your workloads, only Kubernetes-internal components. As a best-practice you should back up what's important to you. For example, any app-level state, such as a database an app might depend on (like MySQL or MongoDB) must be backed up beforehand.
|
||||
|
||||
Also, note that only one minor version upgrade is supported. That is, you can only upgrade from, say 1.7 to 1.8, not from 1.7 to 1.9.
|
||||
|
||||
{{% /capture %}}
|
||||
|
||||
{{% capture steps %}}
|
||||
|
||||
## Upgrading your control plane
|
||||
|
||||
You have to carry out the following steps by executing these commands on your master node:
|
||||
|
||||
1. Install the most recent version of `kubeadm` using `curl` like so:
|
||||
|
||||
{{< caution >}}
|
||||
```shell
|
||||
export VERSION=$(curl -sSL https://dl.k8s.io/release/stable.txt) # or manually specify a released Kubernetes version
|
||||
export ARCH=amd64 # or: arm, arm64, ppc64le, s390x
|
||||
curl -sSL https://dl.k8s.io/release/${VERSION}/bin/linux/${ARCH}/kubeadm > /usr/bin/kubeadm
|
||||
chmod a+rx /usr/bin/kubeadm
|
||||
```
|
||||
**Caution:** Upgrading the `kubeadm` package on your system prior to
|
||||
upgrading the control plane causes a failed upgrade. Even though
|
||||
`kubeadm` is shipped in the Kubernetes repositories, it's important
|
||||
to install `kubeadm` manually. The kubeadm team is working on fixing
|
||||
this limitation.
|
||||
{{< /caution >}}
|
||||
|
||||
Verify that this download of kubeadm works, and has the expected version:
|
||||
|
||||
```shell
|
||||
kubeadm version
|
||||
```
|
||||
|
||||
2. If this the first time you use `kubeadm upgrade`, in order to preserve the configuration for future upgrades, do:
|
||||
|
||||
Note that for below you will need to recall what CLI args you passed to `kubeadm init` the first time.
|
||||
|
||||
If you used flags, do:
|
||||
|
||||
```shell
|
||||
kubeadm config upload from-flags [flags]
|
||||
```
|
||||
|
||||
Where `flags` can be empty.
|
||||
|
||||
If you used a config file, do:
|
||||
|
||||
```shell
|
||||
kubeadm config upload from-file --config [config]
|
||||
```
|
||||
|
||||
Where the `config` is mandatory.
|
||||
|
||||
3. On the master node, run the following:
|
||||
|
||||
```shell
|
||||
kubeadm upgrade plan
|
||||
```
|
||||
|
||||
You should see output similar to this:
|
||||
|
||||
```shell
|
||||
[preflight] Running pre-flight checks
|
||||
[upgrade] Making sure the cluster is healthy:
|
||||
[upgrade/health] Checking API Server health: Healthy
|
||||
[upgrade/health] Checking Node health: All Nodes are healthy
|
||||
[upgrade/health] Checking Static Pod manifests exists on disk: All manifests exist on disk
|
||||
[upgrade/config] Making sure the configuration is correct:
|
||||
[upgrade/config] Reading configuration from the cluster...
|
||||
[upgrade/config] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml'
|
||||
[upgrade] Fetching available versions to upgrade to:
|
||||
[upgrade/versions] Cluster version: v1.7.1
|
||||
[upgrade/versions] kubeadm version: v1.8.0
|
||||
[upgrade/versions] Latest stable version: v1.8.0
|
||||
[upgrade/versions] Latest version in the v1.7 series: v1.7.6
|
||||
|
||||
Components that must be upgraded manually after you've upgraded the control plane with 'kubeadm upgrade apply':
|
||||
COMPONENT CURRENT AVAILABLE
|
||||
Kubelet 1 x v1.7.1 v1.7.6
|
||||
|
||||
Upgrade to the latest version in the v1.7 series:
|
||||
|
||||
COMPONENT CURRENT AVAILABLE
|
||||
API Server v1.7.1 v1.7.6
|
||||
Controller Manager v1.7.1 v1.7.6
|
||||
Scheduler v1.7.1 v1.7.6
|
||||
Kube Proxy v1.7.1 v1.7.6
|
||||
Kube DNS 1.14.4 1.14.4
|
||||
|
||||
You can now apply the upgrade by executing the following command:
|
||||
|
||||
kubeadm upgrade apply v1.7.6
|
||||
|
||||
_____________________________________________________________________
|
||||
|
||||
Components that must be upgraded manually after you've upgraded the control plane with 'kubeadm upgrade apply':
|
||||
COMPONENT CURRENT AVAILABLE
|
||||
Kubelet 1 x v1.7.1 v1.8.0
|
||||
|
||||
Upgrade to the latest stable version:
|
||||
|
||||
COMPONENT CURRENT AVAILABLE
|
||||
API Server v1.7.1 v1.8.0
|
||||
Controller Manager v1.7.1 v1.8.0
|
||||
Scheduler v1.7.1 v1.8.0
|
||||
Kube Proxy v1.7.1 v1.8.0
|
||||
Kube DNS 1.14.4 1.14.4
|
||||
|
||||
You can now apply the upgrade by executing the following command:
|
||||
|
||||
kubeadm upgrade apply v1.8.0
|
||||
|
||||
Note: Before you do can perform this upgrade, you have to update kubeadm to v1.8.0
|
||||
|
||||
_____________________________________________________________________
|
||||
```
|
||||
|
||||
The `kubeadm upgrade plan` checks that your cluster is in an upgradeable state and fetches the versions available to upgrade to in an user-friendly way.
|
||||
|
||||
4. Pick a version to upgrade to and run, for example, `kubeadm upgrade apply` as follows:
|
||||
|
||||
```shell
|
||||
kubeadm upgrade apply v1.8.0
|
||||
```
|
||||
|
||||
You should see output similar to this:
|
||||
|
||||
```shell
|
||||
[preflight] Running pre-flight checks
|
||||
[upgrade] Making sure the cluster is healthy:
|
||||
[upgrade/health] Checking API Server health: Healthy
|
||||
[upgrade/health] Checking Node health: All Nodes are healthy
|
||||
[upgrade/health] Checking Static Pod manifests exists on disk: All manifests exist on disk
|
||||
[upgrade/config] Making sure the configuration is correct:
|
||||
[upgrade/config] Reading configuration from the cluster...
|
||||
[upgrade/config] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml'
|
||||
[upgrade/version] You have chosen to upgrade to version "v1.8.0"
|
||||
[upgrade/versions] Cluster version: v1.7.1
|
||||
[upgrade/versions] kubeadm version: v1.8.0
|
||||
[upgrade/prepull] Will prepull images for components [kube-apiserver kube-controller-manager kube-scheduler]
|
||||
[upgrade/prepull] Prepulling image for component kube-scheduler.
|
||||
[upgrade/prepull] Prepulling image for component kube-apiserver.
|
||||
[upgrade/prepull] Prepulling image for component kube-controller-manager.
|
||||
[apiclient] Found 0 Pods for label selector k8s-app=upgrade-prepull-kube-scheduler
|
||||
[apiclient] Found 1 Pods for label selector k8s-app=upgrade-prepull-kube-scheduler
|
||||
[apiclient] Found 1 Pods for label selector k8s-app=upgrade-prepull-kube-apiserver
|
||||
[apiclient] Found 1 Pods for label selector k8s-app=upgrade-prepull-kube-controller-manager
|
||||
[upgrade/prepull] Prepulled image for component kube-apiserver.
|
||||
[upgrade/prepull] Prepulled image for component kube-controller-manager.
|
||||
[upgrade/prepull] Prepulled image for component kube-scheduler.
|
||||
[upgrade/prepull] Successfully prepulled the images for all the control plane components
|
||||
[upgrade/apply] Upgrading your Static Pod-hosted control plane to version "v1.8.0"...
|
||||
[upgrade/staticpods] Writing upgraded Static Pod manifests to "/etc/kubernetes/tmp/kubeadm-upgraded-manifests432902769"
|
||||
[controlplane] Wrote Static Pod manifest for component kube-apiserver to "/etc/kubernetes/tmp/kubeadm-upgraded-manifests432902769/kube-apiserver.yaml"
|
||||
[controlplane] Wrote Static Pod manifest for component kube-controller-manager to "/etc/kubernetes/tmp/kubeadm-upgraded-manifests432902769/kube-controller-manager.yaml"
|
||||
[controlplane] Wrote Static Pod manifest for component kube-scheduler to "/etc/kubernetes/tmp/kubeadm-upgraded-manifests432902769/kube-scheduler.yaml"
|
||||
[upgrade/staticpods] Moved upgraded manifest to "/etc/kubernetes/manifests/kube-apiserver.yaml" and backed up old manifest to "/etc/kubernetes/tmp/kubeadm-backup-manifests155856668/kube-apiserver.yaml"
|
||||
[upgrade/staticpods] Waiting for the kubelet to restart the component
|
||||
[apiclient] Found 1 Pods for label selector component=kube-apiserver
|
||||
[upgrade/staticpods] Component "kube-apiserver" upgraded successfully!
|
||||
[upgrade/staticpods] Moved upgraded manifest to "/etc/kubernetes/manifests/kube-controller-manager.yaml" and backed up old manifest to "/etc/kubernetes/tmp/kubeadm-backup-manifests155856668/kube-controller-manager.yaml"
|
||||
[upgrade/staticpods] Waiting for the kubelet to restart the component
|
||||
[apiclient] Found 1 Pods for label selector component=kube-controller-manager
|
||||
[upgrade/staticpods] Component "kube-controller-manager" upgraded successfully!
|
||||
[upgrade/staticpods] Moved upgraded manifest to "/etc/kubernetes/manifests/kube-scheduler.yaml" and backed up old manifest to "/etc/kubernetes/tmp/kubeadm-backup-manifests155856668/kube-scheduler.yaml"
|
||||
[upgrade/staticpods] Waiting for the kubelet to restart the component
|
||||
[apiclient] Found 1 Pods for label selector component=kube-scheduler
|
||||
[upgrade/staticpods] Component "kube-scheduler" upgraded successfully!
|
||||
[uploadconfig] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
|
||||
[bootstraptoken] Configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
|
||||
[bootstraptoken] Configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
|
||||
[addons] Applied essential addon: kube-dns
|
||||
[addons] Applied essential addon: kube-proxy
|
||||
|
||||
[upgrade/successful] SUCCESS! Your cluster was upgraded to "v1.8.0". Enjoy!
|
||||
|
||||
[upgrade/kubelet] Now that your control plane is upgraded, please proceed with upgrading your kubelets in turn.
|
||||
```
|
||||
|
||||
`kubeadm upgrade apply` does the following:
|
||||
|
||||
- It checks that your cluster is in an upgradeable state, that is:
|
||||
- The API Server is reachable,
|
||||
- All nodes are in the `Ready` state, and
|
||||
- The control plane is healthy
|
||||
- It enforces the version skew policies.
|
||||
- It makes sure the control plane images are available or available to pull to the machine.
|
||||
- It upgrades the control plane components or rollbacks if any of them fails to come up.
|
||||
- It applies the new `kube-dns` and `kube-proxy` manifests and enforces that all necessary RBAC rules are created.
|
||||
|
||||
5. Manually upgrade your Software Defined Network (SDN).
|
||||
|
||||
Your Container Network Interface (CNI) provider might have its own upgrade instructions to follow now.
|
||||
Check the [addons](/docs/concepts/cluster-administration/addons/) page to
|
||||
find your CNI provider and see if there are additional upgrade steps
|
||||
necessary.
|
||||
|
||||
6. Add RBAC permissions for automated certificate rotation. In the future, kubeadm will perform this step automatically:
|
||||
|
||||
```shell
|
||||
kubectl create clusterrolebinding kubeadm:node-autoapprove-certificate-rotation --clusterrole=system:certificates.k8s.io:certificatesigningrequests:selfnodeclient --group=system:nodes
|
||||
```
|
||||
|
||||
## Upgrading your master and node packages
|
||||
|
||||
For each host (referred to as `$HOST` below) in your cluster, upgrade `kubelet` by executing the following commands:
|
||||
|
||||
1. Prepare the host for maintenance, marking it unschedulable and evicting the workload:
|
||||
|
||||
```shell
|
||||
kubectl drain $HOST --ignore-daemonsets
|
||||
```
|
||||
|
||||
When running this command against the master host, this error is expected and can be safely ignored (since there are static pods running on the master):
|
||||
|
||||
```shell
|
||||
node "master" already cordoned
|
||||
error: pods not managed by ReplicationController, ReplicaSet, Job, DaemonSet or StatefulSet (use --force to override): etcd-kubeadm, kube-apiserver-kubeadm, kube-controller-manager-kubeadm, kube-scheduler-kubeadm
|
||||
```
|
||||
|
||||
2. Upgrade the Kubernetes package versions on the `$HOST` node by using a Linux distribution-specific package manager:
|
||||
|
||||
If the host is running a Debian-based distro such as Ubuntu, run:
|
||||
|
||||
```shell
|
||||
apt-get update
|
||||
apt-get upgrade
|
||||
```
|
||||
|
||||
If the host is running CentOS or the like, run:
|
||||
|
||||
```shell
|
||||
yum update
|
||||
```
|
||||
|
||||
Now the new version of the `kubelet` should be running on the host. Verify this using the following command on `$HOST`:
|
||||
|
||||
```shell
|
||||
systemctl status kubelet
|
||||
```
|
||||
|
||||
3. Bring the host back online by marking it schedulable:
|
||||
|
||||
```shell
|
||||
kubectl uncordon $HOST
|
||||
```
|
||||
|
||||
4. After upgrading `kubelet` on each host in your cluster, verify that all nodes are available again by executing the following (from anywhere, for example, from outside the cluster):
|
||||
|
||||
```shell
|
||||
kubectl get nodes
|
||||
```
|
||||
|
||||
If the `STATUS` column of the above command shows `Ready` for all of your hosts, you are done.
|
||||
|
||||
## Recovering from a bad state
|
||||
|
||||
If `kubeadm upgrade` somehow fails and fails to roll back, due to an unexpected shutdown during execution for instance,
|
||||
you may run `kubeadm upgrade` again as it is idempotent and should eventually make sure the actual state is the desired state you are declaring.
|
||||
|
||||
You can use `kubeadm upgrade` to change a running cluster with `x.x.x --> x.x.x` with `--force`, which can be used to recover from a bad state.
|
||||
|
||||
{{% /capture %}}
|
||||
|
||||
|
||||
@@ -1,264 +0,0 @@
|
||||
---
|
||||
reviewers:
|
||||
- pipejakob
|
||||
- luxas
|
||||
- roberthbailey
|
||||
- jbeda
|
||||
title: Upgrading/downgrading kubeadm clusters between v1.8 to v1.9
|
||||
content_template: templates/task
|
||||
---
|
||||
|
||||
{{% capture overview %}}
|
||||
|
||||
This guide is for upgrading `kubeadm` clusters from version 1.8.x to 1.9.x, as well as 1.8.x to 1.8.y and 1.9.x to 1.9.y where `y > x`.
|
||||
See also [upgrading kubeadm clusters from 1.7 to 1.8](/docs/tasks/administer-cluster/kubeadm-upgrade-1-8/) if you're on a 1.7 cluster currently.
|
||||
|
||||
{{% /capture %}}
|
||||
|
||||
{{% capture prerequisites %}}
|
||||
|
||||
Before proceeding:
|
||||
|
||||
- You need to have a functional `kubeadm` Kubernetes cluster running version 1.8.0 or higher in order to use the process described here. Swap also needs to be disabled.
|
||||
- Make sure you read the [release notes](https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG-1.9.md) carefully.
|
||||
- `kubeadm upgrade` now allows you to upgrade etcd. `kubeadm upgrade` will also upgrade of etcd to 3.1.10 as part of upgrading from v1.8 to v1.9 by default. This is due to the fact that etcd 3.1.10 is the officially validated etcd version for Kubernetes v1.9. The upgrade is handled automatically by kubeadm for you.
|
||||
- Note that `kubeadm upgrade` will not touch any of your workloads, only Kubernetes-internal components. As a best-practice you should back up what's important to you. For example, any app-level state, such as a database an app might depend on (like MySQL or MongoDB) must be backed up beforehand.
|
||||
|
||||
{{< caution >}}
|
||||
**Caution:** All the containers will get restarted after the upgrade, due to container spec hash value gets changed.
|
||||
{{< /caution >}}
|
||||
|
||||
Also, note that only one minor version upgrade is supported. For example, you can only upgrade from 1.8 to 1.9, not from 1.7 to 1.9.
|
||||
|
||||
{{% /capture %}}
|
||||
|
||||
{{% capture steps %}}
|
||||
|
||||
## Upgrading your control plane
|
||||
|
||||
Execute these commands on your master node:
|
||||
|
||||
1. Install the most recent version of `kubeadm` using `curl` like so:
|
||||
|
||||
```shell
|
||||
export VERSION=$(curl -sSL https://dl.k8s.io/release/stable.txt) # or manually specify a released Kubernetes version
|
||||
export ARCH=amd64 # or: arm, arm64, ppc64le, s390x
|
||||
curl -sSL https://dl.k8s.io/release/${VERSION}/bin/linux/${ARCH}/kubeadm > /usr/bin/kubeadm
|
||||
chmod a+rx /usr/bin/kubeadm
|
||||
```
|
||||
|
||||
{{< caution >}}
|
||||
**Caution:** Upgrading the `kubeadm` package on your system prior to upgrading the control plane causes a failed upgrade.
|
||||
Even though `kubeadm` ships in the Kubernetes repositories, it's important to install `kubeadm` manually. The kubeadm
|
||||
team is working on fixing this limitation.
|
||||
{{< /caution >}}
|
||||
|
||||
Verify that this download of kubeadm works and has the expected version:
|
||||
|
||||
```shell
|
||||
kubeadm version
|
||||
```
|
||||
|
||||
2. On the master node, run the following:
|
||||
|
||||
```shell
|
||||
kubeadm upgrade plan
|
||||
```
|
||||
|
||||
You should see output similar to this:
|
||||
|
||||
```shell
|
||||
[preflight] Running pre-flight checks
|
||||
[upgrade] Making sure the cluster is healthy:
|
||||
[upgrade/health] Checking API Server health: Healthy
|
||||
[upgrade/health] Checking Node health: All Nodes are healthy
|
||||
[upgrade/health] Checking Static Pod manifests exists on disk: All manifests exist on disk
|
||||
[upgrade/config] Making sure the configuration is correct:
|
||||
[upgrade/config] Reading configuration from the cluster...
|
||||
[upgrade/config] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml'
|
||||
[upgrade] Fetching available versions to upgrade to:
|
||||
[upgrade/versions] Cluster version: v1.8.1
|
||||
[upgrade/versions] kubeadm version: v1.9.0
|
||||
[upgrade/versions] Latest stable version: v1.9.0
|
||||
[upgrade/versions] Latest version in the v1.8 series: v1.8.6
|
||||
|
||||
Components that must be upgraded manually after you've upgraded the control plane with 'kubeadm upgrade apply':
|
||||
COMPONENT CURRENT AVAILABLE
|
||||
Kubelet 1 x v1.8.1 v1.8.6
|
||||
|
||||
Upgrade to the latest version in the v1.8 series:
|
||||
|
||||
COMPONENT CURRENT AVAILABLE
|
||||
API Server v1.8.1 v1.8.6
|
||||
Controller Manager v1.8.1 v1.8.6
|
||||
Scheduler v1.8.1 v1.8.6
|
||||
Kube Proxy v1.8.1 v1.8.6
|
||||
Kube DNS 1.14.4 1.14.5
|
||||
|
||||
You can now apply the upgrade by executing the following command:
|
||||
|
||||
kubeadm upgrade apply v1.8.6
|
||||
|
||||
_____________________________________________________________________
|
||||
|
||||
Components that must be upgraded manually after you've upgraded the control plane with 'kubeadm upgrade apply':
|
||||
COMPONENT CURRENT AVAILABLE
|
||||
Kubelet 1 x v1.8.1 v1.9.0
|
||||
|
||||
Upgrade to the latest stable version:
|
||||
|
||||
COMPONENT CURRENT AVAILABLE
|
||||
API Server v1.8.1 v1.9.0
|
||||
Controller Manager v1.8.1 v1.9.0
|
||||
Scheduler v1.8.1 v1.9.0
|
||||
Kube Proxy v1.8.1 v1.9.0
|
||||
Kube DNS 1.14.5 1.14.7
|
||||
|
||||
You can now apply the upgrade by executing the following command:
|
||||
|
||||
kubeadm upgrade apply v1.9.0
|
||||
|
||||
Note: Before you do can perform this upgrade, you have to update kubeadm to v1.9.0
|
||||
|
||||
_____________________________________________________________________
|
||||
```
|
||||
|
||||
The `kubeadm upgrade plan` checks that your cluster is upgradeable and fetches the versions available to upgrade to in an user-friendly way.
|
||||
|
||||
To check CoreDNS version, include the `--feature-gates=CoreDNS=true` flag to verify the CoreDNS version which will be installed in place of kube-dns.
|
||||
|
||||
3. Pick a version to upgrade to and run. For example:
|
||||
|
||||
```shell
|
||||
kubeadm upgrade apply v1.9.0
|
||||
```
|
||||
|
||||
You should see output similar to this:
|
||||
|
||||
```shell
|
||||
[preflight] Running pre-flight checks.
|
||||
[upgrade] Making sure the cluster is healthy:
|
||||
[upgrade/config] Making sure the configuration is correct:
|
||||
[upgrade/config] Reading configuration from the cluster...
|
||||
[upgrade/config] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
|
||||
[upgrade/version] You have chosen to upgrade to version "v1.9.0"
|
||||
[upgrade/versions] Cluster version: v1.8.1
|
||||
[upgrade/versions] kubeadm version: v1.9.0
|
||||
[upgrade/confirm] Are you sure you want to proceed with the upgrade? [y/N]: y
|
||||
[upgrade/prepull] Will prepull images for components [kube-apiserver kube-controller-manager kube-scheduler]
|
||||
[upgrade/apply] Upgrading your Static Pod-hosted control plane to version "v1.9.0"...
|
||||
[etcd] Wrote Static Pod manifest for a local etcd instance to "/etc/kubernetes/tmp/kubeadm-upgraded-manifests802453804/etcd.yaml"
|
||||
[upgrade/staticpods] Moved upgraded manifest to "/etc/kubernetes/manifests/etcd.yaml" and backed up old manifest to "/etc/kubernetes/tmp/kubeadm-backup-manifests502223003/etcd.yaml"
|
||||
[upgrade/staticpods] Waiting for the kubelet to restart the component
|
||||
[apiclient] Found 1 Pods for label selector component=etcd
|
||||
[upgrade/staticpods] Component "etcd" upgraded successfully!
|
||||
[upgrade/staticpods] Writing upgraded Static Pod manifests to "/etc/kubernetes/tmp/kubeadm-upgraded-manifests802453804"
|
||||
[controlplane] Wrote Static Pod manifest for component kube-apiserver to "/etc/kubernetes/tmp/kubeadm-upgraded-manifests802453804/kube-apiserver.yaml"
|
||||
[controlplane] Wrote Static Pod manifest for component kube-controller-manager to "/etc/kubernetes/tmp/kubeadm-upgraded-manifests802453804/kube-controller-manager.yaml"
|
||||
[controlplane] Wrote Static Pod manifest for component kube-scheduler to "/etc/kubernetes/tmp/kubeadm-upgraded-manifests802453804/kube-scheduler.yaml"
|
||||
[upgrade/staticpods] Moved upgraded manifest to "/etc/kubernetes/manifests/kube-apiserver.yaml" and backed up old manifest to "/etc/kubernetes/tmp/kubeadm-backup-manifests502223003/kube-apiserver.yaml"
|
||||
[upgrade/staticpods] Waiting for the kubelet to restart the component
|
||||
[apiclient] Found 1 Pods for label selector component=kube-apiserver
|
||||
[upgrade/staticpods] Component "kube-apiserver" upgraded successfully!
|
||||
[upgrade/staticpods] Moved upgraded manifest to "/etc/kubernetes/manifests/kube-controller-manager.yaml" and backed up old manifest to "/etc/kubernetes/tmp/kubeadm-backup-manifests502223003/kube-controller-manager.yaml"
|
||||
[upgrade/staticpods] Waiting for the kubelet to restart the component
|
||||
[apiclient] Found 1 Pods for label selector component=kube-controller-manager
|
||||
[upgrade/staticpods] Component "kube-controller-manager" upgraded successfully!
|
||||
[upgrade/staticpods] Moved upgraded manifest to "/etc/kubernetes/manifests/kube-scheduler.yaml" and backed up old manifest to "/etc/kubernetes/tmp/kubeadm-backup-manifests502223003/kube-scheduler.yaml"
|
||||
[upgrade/staticpods] Waiting for the kubelet to restart the component
|
||||
[apiclient] Found 1 Pods for label selector component=kube-scheduler
|
||||
[upgrade/staticpods] Component "kube-scheduler" upgraded successfully!
|
||||
[uploadconfig] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
|
||||
[bootstraptoken] Configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
|
||||
[bootstraptoken] Configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
|
||||
[bootstraptoken] Configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
|
||||
[addons] Applied essential addon: kube-dns
|
||||
[addons] Applied essential addon: kube-proxy
|
||||
|
||||
[upgrade/successful] SUCCESS! Your cluster was upgraded to "v1.9.0". Enjoy!
|
||||
|
||||
[upgrade/kubelet] Now that your control plane is upgraded, please proceed with upgrading your kubelets in turn.
|
||||
```
|
||||
|
||||
To upgrade the cluster with CoreDNS as the default internal DNS, invoke `kubeadm upgrade apply` with the `--feature-gates=CoreDNS=true` flag.
|
||||
`kubeadm upgrade apply` does the following:
|
||||
|
||||
- Checks that your cluster is in an upgradeable state:
|
||||
- The API server is reachable,
|
||||
- All nodes are in the `Ready` state
|
||||
- The control plane is healthy
|
||||
- Enforces the version skew policies.
|
||||
- Makes sure the control plane images are available or available to pull to the machine.
|
||||
- Upgrades the control plane components or rollbacks if any of them fails to come up.
|
||||
- Applies the new `kube-dns` and `kube-proxy` manifests and enforces that all necessary RBAC rules are created.
|
||||
- Creates new certificate and key files of apiserver and backs up old files if they're about to expire in 180 days.
|
||||
|
||||
4. Manually upgrade your Software Defined Network (SDN).
|
||||
|
||||
Your Container Network Interface (CNI) provider may have its own upgrade instructions to follow.
|
||||
Check the [addons](/docs/concepts/cluster-administration/addons/) page to
|
||||
find your CNI provider and see if there are additional upgrade steps
|
||||
necessary.
|
||||
|
||||
## Upgrading your master and node packages
|
||||
|
||||
For each host (referred to as `$HOST` below) in your cluster, upgrade `kubelet` by executing the following commands:
|
||||
|
||||
1. Prepare the host for maintenance, marking it unschedulable and evicting the workload:
|
||||
|
||||
```shell
|
||||
kubectl drain $HOST --ignore-daemonsets
|
||||
```
|
||||
|
||||
When running this command against the master host, this error is expected and can be safely ignored (since there are static pods running on the master):
|
||||
|
||||
```shell
|
||||
node "master" already cordoned
|
||||
error: pods not managed by ReplicationController, ReplicaSet, Job, DaemonSet or StatefulSet (use --force to override): etcd-kubeadm, kube-apiserver-kubeadm, kube-controller-manager-kubeadm, kube-scheduler-kubeadm
|
||||
```
|
||||
|
||||
2. Upgrade the Kubernetes package versions on the `$HOST` node by using a Linux distribution-specific package manager:
|
||||
|
||||
If the host is running a Debian-based distro such as Ubuntu, run:
|
||||
|
||||
```shell
|
||||
apt-get update
|
||||
apt-get upgrade
|
||||
```
|
||||
|
||||
If the host is running CentOS or the like, run:
|
||||
|
||||
```shell
|
||||
yum update
|
||||
```
|
||||
|
||||
Now the new version of the `kubelet` should be running on the host. Verify this using the following command on `$HOST`:
|
||||
|
||||
```shell
|
||||
systemctl status kubelet
|
||||
```
|
||||
|
||||
3. Bring the host back online by marking it schedulable:
|
||||
|
||||
```shell
|
||||
kubectl uncordon $HOST
|
||||
```
|
||||
|
||||
4. After upgrading `kubelet` on each host in your cluster, verify that all nodes are available again by executing the following (from anywhere, for example, from outside the cluster):
|
||||
|
||||
```shell
|
||||
kubectl get nodes
|
||||
```
|
||||
|
||||
If the `STATUS` column of the above command shows `Ready` for all of your hosts, you are done.
|
||||
|
||||
## Recovering from a failure state
|
||||
|
||||
If `kubeadm upgrade` somehow fails and fails to roll back, for example due to an unexpected shutdown during execution,
|
||||
you can run `kubeadm upgrade` again as it is idempotent and should eventually make sure the actual state is the desired state you are declaring.
|
||||
|
||||
You can use `kubeadm upgrade` to change a running cluster with `x.x.x --> x.x.x` with `--force`, which can be used to recover from a bad state.
|
||||
|
||||
{{% /capture %}}
|
||||
|
||||
|
||||
@@ -1,16 +1,16 @@
|
||||
---
|
||||
reviewers:
|
||||
- jamiehannaford
|
||||
- jamiehannaford
|
||||
- luxas
|
||||
- timothysc
|
||||
- timothysc
|
||||
- jbeda
|
||||
title: Upgrading kubeadm HA clusters from 1.9.x to 1.9.y
|
||||
title: Upgrading kubeadm HA clusters from v1.11 to v1.12
|
||||
content_template: templates/task
|
||||
---
|
||||
|
||||
{{% capture overview %}}
|
||||
|
||||
This guide is for upgrading `kubeadm` HA clusters from version 1.9.x to 1.9.y where `y > x`. The term "`kubeadm` HA clusters" refers to clusters of more than one master node created with `kubeadm`. To set up an HA cluster for Kubernetes version 1.9.x `kubeadm` requires additional manual steps. See [Creating HA clusters with kubeadm](/docs/setup/independent/high-availability/) for instructions on how to do this. The upgrade procedure described here targets clusters created following those very instructions. See [Upgrading/downgrading kubeadm clusters between v1.8 to v1.9](/docs/tasks/administer-cluster/kubeadm-upgrade-1-9/) for more instructions on how to create an HA cluster with `kubeadm`.
|
||||
This page explains how to upgrade a highly available (HA) Kubernetes cluster created with `kubeadm` from version 1.11.x to version 1.12.x. In addition to upgrading, you must also follow the instructions in [Creating HA clusters with kubeadm](/docs/setup/independent/high-availability/).
|
||||
|
||||
{{% /capture %}}
|
||||
|
||||
@@ -18,119 +18,223 @@ This guide is for upgrading `kubeadm` HA clusters from version 1.9.x to 1.9.y wh
|
||||
|
||||
Before proceeding:
|
||||
|
||||
- You need to have a functional `kubeadm` HA cluster running version 1.9.0 or higher in order to use the process described here.
|
||||
- Make sure you read the [release notes](https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG-1.9.md) carefully.
|
||||
- Note that `kubeadm upgrade` will not touch any of your workloads, only Kubernetes-internal components. As a best-practice you should back up anything important to you. For example, any application-level state, such as a database and application might depend on (like MySQL or MongoDB) should be backed up beforehand.
|
||||
- Read [Upgrading/downgrading kubeadm clusters between v1.8 to v1.9](/docs/tasks/administer-cluster/kubeadm-upgrade-1-9/) to learn about the relevant prerequisites.
|
||||
- You need to have a `kubeadm` HA cluster running version 1.11 or higher.
|
||||
- Make sure you read the [release notes](https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG-1.12.md) carefully.
|
||||
- Make sure to back up any important components, such as app-level state stored in a database. `kubeadm upgrade` does not touch your workloads, only components internal to Kubernetes, but backups are always a best practice.
|
||||
- Check the prerequisites for [Upgrading/downgrading kubeadm clusters between v1.11 to v1.12](/docs/tasks/administer-cluster/kubeadm-upgrade-1-12/).
|
||||
|
||||
{{< note >}}
|
||||
**Note**: All commands on any control plane or etcd node should be
|
||||
run as root.
|
||||
{{< /note >}}
|
||||
|
||||
{{% /capture %}}
|
||||
|
||||
{{% capture steps %}}
|
||||
|
||||
## Preparation
|
||||
## Prepare for both methods
|
||||
|
||||
Some preparation is needed prior to starting the upgrade. First download the version of `kubeadm` that matches the version of Kubernetes that you are upgrading to:
|
||||
Upgrade `kubeadm` to the version that matches the version of Kubernetes that you are upgrading to:
|
||||
|
||||
```shell
|
||||
# Use the latest stable release or manually specify a
|
||||
# released Kubernetes version
|
||||
export VERSION=$(curl -sSL https://dl.k8s.io/release/stable.txt)
|
||||
export ARCH=amd64 # or: arm, arm64, ppc64le, s390x
|
||||
curl -sSL https://dl.k8s.io/release/${VERSION}/bin/linux/${ARCH}/kubeadm > /tmp/kubeadm
|
||||
chmod a+rx /tmp/kubeadm
|
||||
apt-mark unhold kubeadm && \
|
||||
apt-get update && apt-get install -y kubeadm && \
|
||||
apt-mark hold kubeadm
|
||||
```
|
||||
|
||||
Copy this file to `/tmp` on your primary master if necessary. Run this command for checking prerequisites and determining the versions you will receive:
|
||||
Check prerequisites and determine the upgrade versions:
|
||||
|
||||
```shell
|
||||
/tmp/kubeadm upgrade plan
|
||||
kubeadm upgrade plan
|
||||
```
|
||||
|
||||
If the prerequisites are met you'll get a summary of the software versions kubeadm will upgrade to, like this:
|
||||
You should see something like the following:
|
||||
|
||||
Upgrade to the latest stable version:
|
||||
|
||||
COMPONENT CURRENT AVAILABLE
|
||||
API Server v1.9.0 v1.9.2
|
||||
Controller Manager v1.9.0 v1.9.2
|
||||
Scheduler v1.9.0 v1.9.2
|
||||
Kube Proxy v1.9.0 v1.9.2
|
||||
Kube DNS 1.14.5 1.14.7
|
||||
Etcd 3.2.7 3.1.11
|
||||
API Server v1.11.3 v1.12.0
|
||||
Controller Manager v1.11.3 v1.12.0
|
||||
Scheduler v1.11.3 v1.12.0
|
||||
Kube Proxy v1.11.3 v1.12.0
|
||||
CoreDNS 1.1.3 1.2.2
|
||||
Etcd 3.2.18 3.2.24
|
||||
|
||||
{{< caution >}}
|
||||
**Caution:** Currently the only supported configuration for kubeadm HA clusters requires the use of an externally managed etcd cluster. Upgrading etcd is not supported as a part of the upgrade. If necessary you will have to upgrade the etcd cluster according to [etcd's upgrade instructions](/docs/tasks/administer-cluster/configure-upgrade-etcd/), which is beyond the scope of these instructions.
|
||||
{{< /caution >}}
|
||||
## Stacked control plane nodes
|
||||
|
||||
## Upgrading your control plane
|
||||
### Upgrade the first control plane node
|
||||
|
||||
The following procedure must be applied on a single master node and repeated for each subsequent master node sequentially.
|
||||
|
||||
Before initiating the upgrade with `kubeadm` `configmap/kubeadm-config` needs to be modified for the current master host. Replace any hard reference to a master host name with the current master hosts' name:
|
||||
Modify `configmap/kubeadm-config` for this control plane node:
|
||||
|
||||
```shell
|
||||
kubectl get configmap -n kube-system kubeadm-config -o yaml >/tmp/kubeadm-config-cm.yaml
|
||||
sed -i 's/^\([ \t]*nodeName:\).*/\1 <CURRENT-MASTER-NAME>/' /tmp/kubeadm-config-cm.yaml
|
||||
kubectl apply -f /tmp/kubeadm-config-cm.yaml --force
|
||||
kubectl get configmap -n kube-system kubeadm-config -o yaml > kubeadm-config-cm.yaml
|
||||
```
|
||||
|
||||
Now the upgrade process can start. Use the target version determined in the preparation step and run the following command (press “y” when prompted):
|
||||
Open the file in an editor and replace the following values:
|
||||
|
||||
- `api.advertiseAddress`
|
||||
|
||||
This should be set to the local node's IP address.
|
||||
|
||||
- `etcd.local.extraArgs.advertise-client-urls`
|
||||
|
||||
This should be updated to the local node's IP address.
|
||||
|
||||
- `etcd.local.extraArgs.initial-advertise-peer-urls`
|
||||
|
||||
This should be updated to the local node's IP address.
|
||||
|
||||
- `etcd.local.extraArgs.listen-client-urls`
|
||||
|
||||
This should be updated to the local node's IP address.
|
||||
|
||||
- `etcd.local.extraArgs.listen-peer-urls`
|
||||
|
||||
This should be updated to the local node's IP address.
|
||||
|
||||
- `etcd.local.extraArgs.initial-cluster`
|
||||
|
||||
This should be updated to include the hostname and IP address pairs for each control plane node in the cluster. For example:
|
||||
|
||||
"ip-172-31-92-42=https://172.31.92.42:2380,ip-172-31-89-186=https://172.31.89.186:2380,ip-172-31-90-42=https://172.31.90.42:2380"
|
||||
|
||||
You must also pass an additional argument (`initial-cluster-state: existing`) to etcd.local.extraArgs.
|
||||
|
||||
```shell
|
||||
/tmp/kubeadm upgrade apply v<YOUR-CHOSEN-VERSION-HERE>
|
||||
kubectl apply -f kubeadm-config-cm.yaml --force
|
||||
```
|
||||
|
||||
If the operation was successful you’ll get a message like this:
|
||||
|
||||
[upgrade/successful] SUCCESS! Your cluster was upgraded to "v1.9.2". Enjoy!
|
||||
|
||||
To upgrade the cluster with CoreDNS as the default internal DNS, invoke `kubeadm upgrade apply` with the `--feature-gates=CoreDNS=true` flag.
|
||||
|
||||
Next, manually upgrade your CNI provider
|
||||
|
||||
Your Container Network Interface (CNI) provider may have its own upgrade instructions to follow. Check the [addons](/docs/concepts/cluster-administration/addons/) page to find your CNI provider and see if there are additional upgrade steps necessary.
|
||||
|
||||
{{< note >}}
|
||||
**Note:** The `kubeadm upgrade apply` step has been known to fail when run initially on the secondary masters (timed out waiting for the restarted static pods to come up). It should succeed if retried after a minute or two.
|
||||
{{< /note >}}
|
||||
|
||||
## Upgrade base software packages
|
||||
|
||||
At this point all the static pod manifests in your cluster, for example API Server, Controller Manager, Scheduler, Kube Proxy have been upgraded, however the base software, for example `kubelet`, `kubectl`, `kubeadm` installed on your nodes’ OS are still of the old version. For upgrading the base software packages we will upgrade them and restart services on all nodes one by one:
|
||||
Start the upgrade:
|
||||
|
||||
```shell
|
||||
# use your distro's package manager, e.g. 'yum' on RH-based systems
|
||||
kubeadm upgrade apply v<YOUR-CHOSEN-VERSION-HERE>
|
||||
```
|
||||
|
||||
You should see something like the following:
|
||||
|
||||
[upgrade/successful] SUCCESS! Your cluster was upgraded to "v1.12.0". Enjoy!
|
||||
|
||||
The `kubeadm-config` ConfigMap is now updated from `v1alpha2` version to `v1alpha3`.
|
||||
|
||||
### Upgrading additional control plane nodes
|
||||
|
||||
Each additional control plane node requires modifications that are different from the first control plane node. Run:
|
||||
|
||||
```shell
|
||||
kubectl get configmap -n kube-system kubeadm-config -o yaml > kubeadm-config-cm.yaml
|
||||
```
|
||||
|
||||
Open the file in an editor and replace the following values for `ClusterConfiguration`:
|
||||
|
||||
- `etcd.local.extraArgs.advertise-client-urls`
|
||||
|
||||
This should be updated to the local node's IP address.
|
||||
|
||||
- `etcd.local.extraArgs.initial-advertise-peer-urls`
|
||||
|
||||
This should be updated to the local node's IP address.
|
||||
|
||||
- `etcd.local.extraArgs.listen-client-urls`
|
||||
|
||||
This should be updated to the local node's IP address.
|
||||
|
||||
- `etcd.local.extraArgs.listen-peer-urls`
|
||||
|
||||
This should be updated to the local node's IP address.
|
||||
|
||||
You must also modify the `ClusterStatus` to add a mapping for the current host under apiEndpoints.
|
||||
|
||||
Add an annotation for the cri-socket to the current node, for example to use docker:
|
||||
|
||||
```shell
|
||||
kubectl annotate node <nodename> kubeadm.alpha.kubernetes.io/cri-socket=/var/run/dockershim.sock
|
||||
```
|
||||
|
||||
Start the upgrade:
|
||||
|
||||
```shell
|
||||
kubeadm upgrade apply v<YOUR-CHOSEN-VERSION-HERE>
|
||||
```
|
||||
|
||||
You should see something like the following:
|
||||
|
||||
[upgrade/successful] SUCCESS! Your cluster was upgraded to "v1.12.0". Enjoy!
|
||||
|
||||
## External etcd
|
||||
|
||||
### Upgrade each control plane
|
||||
|
||||
Get a copy of the kubeadm config used to create this cluster. The config should be the same for every node. The config must exist on every control plane node before the upgrade begins.
|
||||
|
||||
```
|
||||
# on each control plane node
|
||||
kubectl get configmap -n kube-system kubeadm-config -o jsonpath={.data.MasterConfiguration} > kubeadm-config.yaml
|
||||
```
|
||||
|
||||
Now run the upgrade on each control plane node one at a time.
|
||||
|
||||
```
|
||||
kubeadm upgrade apply v1.12.0 --config kubeadm-config.yaml
|
||||
```
|
||||
|
||||
### Upgrade etcd
|
||||
|
||||
Kubernetes v1.11 to v1.12 only changed the patch version of etcd from v3.2.18 to v3.2.24. This is a rolling upgrade with no downtime, because you can run both versions in the same cluster.
|
||||
|
||||
On the first host, modify the etcd manifest:
|
||||
|
||||
```shell
|
||||
sed -i 's/3.2.18/3.2.24/' /etc/kubernetes/manifests/etcd.yaml
|
||||
```
|
||||
|
||||
Wait for the etcd process to reconnect. There will be error warnings in the other etcd node logs. This is expected.
|
||||
|
||||
Repeat this step on the other etcd hosts.
|
||||
|
||||
## Next steps
|
||||
|
||||
### Manually upgrade your CNI provider
|
||||
|
||||
Your Container Network Interface (CNI) provider might have its own upgrade instructions to follow. Check the [addons](/docs/concepts/cluster-administration/addons/) page to find your CNI provider and see whether you need to take additional upgrade steps.
|
||||
|
||||
### Update kubelet and kubectl packages
|
||||
|
||||
Upgrade the kubelet and kubectl by running the following on each node:
|
||||
|
||||
```shell
|
||||
# use your distro's package manager, e.g. 'apt-get' on Debian-based systems
|
||||
# for the versions stick to kubeadm's output (see above)
|
||||
yum install -y kubelet-<NEW-K8S-VERSION> kubectl-<NEW-K8S-VERSION> kubeadm-<NEW-K8S-VERSION> kubernetes-cni-<NEW-CNI-VERSION>
|
||||
apt-mark unhold kubelet kubectl && \
|
||||
apt-get update && \
|
||||
apt-get install kubelet=<NEW-K8S-VERSION> kubectl=<NEW-K8S-VERSION> && \
|
||||
apt-mark hold kubelet kubectl && \
|
||||
systemctl restart kubelet
|
||||
```
|
||||
|
||||
In this example an _rpm_-based system is assumed and `yum` is used for installing the upgraded software. On _deb_-based systems it will be `apt-get update` and then `apt-get install <PACKAGE>=<NEW-K8S-VERSION>` for all packages.
|
||||
In this example a _deb_-based system is assumed and `apt-get` is used for installing the upgraded software. On rpm-based systems the command is `yum install <PACKAGE>=<NEW-K8S-VERSION>` for all packages.
|
||||
|
||||
Now the new version of the `kubelet` should be running on the host. Verify this using the following command on the respective host:
|
||||
Verify that the new version of the kubelet is running:
|
||||
|
||||
```shell
|
||||
systemctl status kubelet
|
||||
```
|
||||
|
||||
Verify that the upgraded node is available again by executing the following from wherever you run `kubectl` commands:
|
||||
Verify that the upgraded node is available again by running the following command from wherever you run `kubectl`:
|
||||
|
||||
```shell
|
||||
kubectl get nodes
|
||||
```
|
||||
|
||||
If the `STATUS` column of the above command shows `Ready` for the upgraded host, you can continue (you may have to repeat this for a couple of time before the node gets `Ready`).
|
||||
If the `STATUS` column shows `Ready` for the upgraded host, you can continue. You might need to repeat the command until the node shows `Ready`.
|
||||
|
||||
## If something goes wrong
|
||||
|
||||
If the upgrade fails the situation afterwards depends on the phase in which things went wrong:
|
||||
If the upgrade fails, see whether one of the following scenarios applies:
|
||||
|
||||
1. If `/tmp/kubeadm upgrade apply` failed to upgrade the cluster it will try to perform a rollback. Hence if that happened on the first master, chances are pretty good that the cluster is still intact.
|
||||
- If `kubeadm upgrade apply` failed to upgrade the cluster, it will try to perform a rollback. If this is the case on the first master, the cluster is probably still intact.
|
||||
|
||||
You can run `/tmp/kubeadm upgrade apply` again as it is idempotent and should eventually make sure the actual state is the desired state you are declaring. You can use `/tmp/kubeadm upgrade apply` to change a running cluster with `x.x.x --> x.x.x` with `--force`, which can be used to recover from a bad state.
|
||||
You can run `kubeadm upgrade apply` again, because it is idempotent and should eventually make sure the actual state is the desired state you are declaring. You can run `kubeadm upgrade apply` to change a running cluster with `x.x.x --> x.x.x` with `--force` to recover from a bad state.
|
||||
|
||||
2. If `/tmp/kubeadm upgrade apply` on one of the secondary masters failed you still have a working, upgraded cluster, but with the secondary masters in a somewhat undefined condition. You will have to find out what went wrong and join the secondaries manually. As mentioned above, sometimes upgrading one of the secondary masters fails waiting for the restarted static pods first, but succeeds when the operation is simply repeated after a little pause of one or two minutes.
|
||||
- If `kubeadm upgrade apply` on one of the secondary masters failed, the cluster is upgraded and working, but the secondary masters are in an undefined state. You need to investigate further and join the secondaries manually.
|
||||
|
||||
{{% /capture %}}
|
||||
|
||||
|
||||
|
||||
@@ -250,12 +250,58 @@ spec:
|
||||
TODO: Test and explain how to use additional non-K8s secrets with an existing service account.
|
||||
-->
|
||||
|
||||
## Service Account Volume Projection
|
||||
## Service Account Token Volume Projection
|
||||
|
||||
Kubernetes 1.11 and higher supports a new way to project a service account token into a Pod.
|
||||
You can specify a token request with audiences, expirationSeconds. The service account token
|
||||
becomes invalid when the Pod is deleted. A Projected Volume named
|
||||
[ServiceAccountToken](/docs/concepts/storage/volumes/#projected) requests and stores the token.
|
||||
{{< feature-state for_k8s_version="v1.12" state="beta" >}}
|
||||
|
||||
{{< note >}}
|
||||
**Note:** This ServiceAccountTokenVolumeProjection is __beta__ in 1.12 and
|
||||
enabled by passing all of the following flags to the API server:
|
||||
|
||||
* `--service-account-issuer`
|
||||
* `--service-account-signing-key-file`
|
||||
* `--service-account-api-audiences`
|
||||
|
||||
{{< /note >}}
|
||||
|
||||
The kubelet can also project a service account token into a Pod. You can
|
||||
specify desired properties of the token, such as the audience and the validity
|
||||
duration. These properties are not configurable on the default service account
|
||||
token. The service account token will also become invalid against the API when
|
||||
the Pod or the ServiceAccount is deleted.
|
||||
|
||||
This behavior is configured on a PodSpec using a ProjectedVolume type called
|
||||
[ServiceAccountToken](/docs/concepts/storage/volumes/#projected). To provide a
|
||||
pod with a token with an audience of "vault" and a validity duration of two
|
||||
hours, you would configure the following in your PodSpec:
|
||||
|
||||
```yaml
|
||||
kind: Pod
|
||||
apiVersion: v1
|
||||
spec:
|
||||
containers:
|
||||
- image: nginx
|
||||
name: nginx
|
||||
volumeMounts:
|
||||
- mountPath: /var/run/secrets/tokens
|
||||
name: vault-token
|
||||
volumes:
|
||||
- name: vault-token
|
||||
projected:
|
||||
sources:
|
||||
- serviceAccountToken:
|
||||
path: vault-token
|
||||
expirationSeconds: 7200
|
||||
audience: vault
|
||||
```
|
||||
|
||||
The kubelet will request and store the token on behalf of the pod, make the
|
||||
token avaialble to the pod at a configurable file path, and refresh the token as
|
||||
it approaches expiration. Kubelet proactively rotates the token if it is older
|
||||
than 80% of its total TTL, or if the token is older than 24 hours.
|
||||
|
||||
The application is responsible for reloading the token when it rotates. Periodic
|
||||
reloading (e.g. once every 5 minutes) is sufficient for most usecases.
|
||||
|
||||
{{% /capture %}}
|
||||
|
||||
|
||||
@@ -11,7 +11,7 @@ weight: 160
|
||||
|
||||
{{% capture overview %}}
|
||||
|
||||
{{< feature-state state="alpha" >}}
|
||||
{{< feature-state state="beta" >}}
|
||||
|
||||
This page shows how to configure process namespace sharing for a pod. When
|
||||
process namespace sharing is enabled, processes in a container are visible
|
||||
@@ -27,8 +27,8 @@ include debugging utilities like a shell.
|
||||
|
||||
{{< include "task-tutorial-prereqs.md" >}} {{< version-check >}}
|
||||
|
||||
A special **alpha** feature gate `PodShareProcessNamespace` must be set to true
|
||||
across the system: `--feature-gates=PodShareProcessNamespace=true`.
|
||||
Process Namespace Sharing is a **beta** feature that is enabled by default. It
|
||||
may be disabled by setting `--feature-gates=PodShareProcessNamespace=false`.
|
||||
|
||||
{{% /capture %}}
|
||||
|
||||
|
||||
@@ -9,8 +9,6 @@ title: Auditing
|
||||
|
||||
{{% capture overview %}}
|
||||
|
||||
{{< feature-state state="beta" >}}
|
||||
|
||||
Kubernetes auditing provides a security-relevant chronological set of records documenting
|
||||
the sequence of activities that have affected system by individual users, administrators
|
||||
or other components of the system. It allows cluster administrator to
|
||||
@@ -83,7 +81,7 @@ You can use a minimal audit policy file to log all requests at the `Metadata` le
|
||||
|
||||
```yaml
|
||||
# Log all requests at the Metadata level.
|
||||
apiVersion: audit.k8s.io/v1beta1
|
||||
apiVersion: audit.k8s.io/v1
|
||||
kind: Policy
|
||||
rules:
|
||||
- level: Metadata
|
||||
@@ -102,7 +100,7 @@ Audit backends persist audit events to an external storage.
|
||||
|
||||
In both cases, audit events structure is defined by the API in the
|
||||
`audit.k8s.io` API group. The current version of the API is
|
||||
[`v1beta1`][auditing-api].
|
||||
[`v1`][auditing-api].
|
||||
|
||||
{{< note >}}
|
||||
**Note:** In case of patches, request body is a JSON array with patch operations, not a JSON object
|
||||
@@ -363,54 +361,11 @@ Note that in addition to file output plugin, logstash has a variety of outputs t
|
||||
let users route data where they want. For example, users can emit audit events to elasticsearch
|
||||
plugin which supports full-text search and analytics.
|
||||
|
||||
## Legacy Audit
|
||||
|
||||
__Note:__ Legacy Audit is deprecated and is disabled by default since 1.8 and
|
||||
will be removed in 1.12. To fallback to this legacy audit, disable the advanced
|
||||
auditing feature using the `AdvancedAuditing` feature gate in [kube-apiserver][kube-apiserver]:
|
||||
|
||||
```
|
||||
--feature-gates=AdvancedAuditing=false
|
||||
```
|
||||
|
||||
In legacy format, each audit log entry contains two lines:
|
||||
|
||||
1. The request line containing a unique ID to match the response and request
|
||||
metadata, such as the source IP, requesting user, impersonation information,
|
||||
resource being requested, etc.
|
||||
2. The response line containing a unique ID matching the request line and the response code.
|
||||
|
||||
Example output for `admin` user listing pods in the `default` namespace:
|
||||
|
||||
```
|
||||
2017-03-21T03:57:09.106841886-04:00 AUDIT: id="c939d2a7-1c37-4ef1-b2f7-4ba9b1e43b53" ip="127.0.0.1" method="GET" user="admin" groups="\"system:masters\",\"system:authenticated\"" as="<self>" asgroups="<lookup>" namespace="default" uri="/api/v1/namespaces/default/pods"
|
||||
2017-03-21T03:57:09.108403639-04:00 AUDIT: id="c939d2a7-1c37-4ef1-b2f7-4ba9b1e43b53" response="200"
|
||||
```
|
||||
|
||||
### Configuration
|
||||
|
||||
[Kube-apiserver][kube-apiserver] provides the following options which are responsible
|
||||
for configuring where and how audit logs are handled:
|
||||
|
||||
- `audit-log-path` - enables the audit log pointing to a file where the requests are being logged to, '-' means standard out.
|
||||
- `audit-log-maxage` - specifies maximum number of days to retain old audit log files based on the timestamp encoded in their filename.
|
||||
- `audit-log-maxbackup` - specifies maximum number of old audit log files to retain.
|
||||
- `audit-log-maxsize` - specifies maximum size in megabytes of the audit log file before it gets rotated. Defaults to 100MB.
|
||||
|
||||
If an audit log file already exists, Kubernetes appends new audit logs to that file.
|
||||
Otherwise, Kubernetes creates an audit log file at the location you specified in
|
||||
`audit-log-path`. If the audit log file exceeds the size you specify in `audit-log-maxsize`,
|
||||
Kubernetes will rename the current log file by appending the current timestamp on
|
||||
the file name (before the file extension) and create a new audit log file.
|
||||
Kubernetes may delete old log files when creating a new log file; you can configure
|
||||
how many files are retained and how old they can be by specifying the `audit-log-maxbackup`
|
||||
and `audit-log-maxage` options.
|
||||
|
||||
[kube-apiserver]: /docs/admin/kube-apiserver
|
||||
[auditing-proposal]: https://github.com/kubernetes/community/blob/master/contributors/design-proposals/api-machinery/auditing.md
|
||||
[auditing-api]: https://github.com/kubernetes/kubernetes/blob/{{< param "githubbranch" >}}/staging/src/k8s.io/apiserver/pkg/apis/audit/v1beta1/types.go
|
||||
[auditing-api]: https://github.com/kubernetes/kubernetes/blob/{{< param "githubbranch" >}}/staging/src/k8s.io/apiserver/pkg/apis/audit/v1/types.go
|
||||
[gce-audit-profile]: https://github.com/kubernetes/kubernetes/blob/{{< param "githubbranch" >}}/cluster/gce/gci/configure-helper.sh#L735
|
||||
[kubeconfig]: https://kubernetes.io/docs/tasks/access-application-cluster/configure-access-multiple-clusters/
|
||||
[kubeconfig]: /docs/tasks/access-application-cluster/configure-access-multiple-clusters/
|
||||
[fluentd]: http://www.fluentd.org/
|
||||
[fluentd_install_doc]: http://docs.fluentd.org/v0.12/articles/quickstart#step1-installing-fluentd
|
||||
[fluentd_plugin_management_doc]: https://docs.fluentd.org/v0.12/articles/plugin-management
|
||||
|
||||
@@ -1,7 +1,8 @@
|
||||
---
|
||||
title: Extend kubectl with plugins
|
||||
reviewers:
|
||||
- fabianofranz
|
||||
- juanvallejo
|
||||
- soltysh
|
||||
description: With kubectl plugins, you can extend the functionality of the kubectl command by adding new subcommands.
|
||||
content_template: templates/task
|
||||
---
|
||||
@@ -10,7 +11,8 @@ content_template: templates/task
|
||||
|
||||
{{< feature-state state="alpha" >}}
|
||||
|
||||
This guide shows you how to install and write extensions for [kubectl](/docs/user-guide/kubectl/). Usually called *plugins* or *binary extensions*, this feature allows you to extend the default set of commands available in `kubectl` by adding new subcommands to perform new tasks and extend the set of features available in the main distribution of `kubectl`.
|
||||
This guide demonstrates how to install and write extensions for [kubectl](/docs/reference/kubectl/kubectl/). By thinking of core `kubectl` commands as essential building blocks for interacting with a Kubernetes cluster, a cluster administrator can think
|
||||
of plugins as a means of utilizing these building blocks to create more complex behavior. Plugins extend `kubectl` with new sub-commands, allowing for new and custom features not included in the main distribution of `kubectl`.
|
||||
|
||||
{{% /capture %}}
|
||||
|
||||
@@ -18,10 +20,10 @@ This guide shows you how to install and write extensions for [kubectl](/docs/use
|
||||
|
||||
You need to have a working `kubectl` binary installed.
|
||||
{{< note >}}
|
||||
**Note:** Plugins were officially introduced as an alpha feature in the v1.8.0 release. So, while some parts of the plugins feature were already available in previous versions, a `kubectl` version of 1.8.0 or later is recommended.
|
||||
**Note:** Plugins were officially introduced as an alpha feature in the v1.8.0 release. They have been re-worked in the v1.12.0 release to support a wider range of use-cases. So, while some parts of the plugins feature were already available in previous versions, a `kubectl` version of 1.12.0 or later is recommended if you are following these docs.
|
||||
{{< /note >}}
|
||||
|
||||
Until a GA version is released, plugins will only be available under the `kubectl plugin` subcommand.
|
||||
Until a GA version is released, plugins should be considered unstable, and their underlying mechanism is prone to change.
|
||||
|
||||
{{% /capture %}}
|
||||
|
||||
@@ -29,112 +31,246 @@ Until a GA version is released, plugins will only be available under the `kubect
|
||||
|
||||
## Installing kubectl plugins
|
||||
|
||||
A plugin is nothing more than a set of files: at least a **plugin.yaml** descriptor, and likely one or more binary, script, or assets files. To install a plugin, copy those files to one of the locations in the filesystem where `kubectl` searches for plugins.
|
||||
A plugin is nothing more than a standalone executable file, whose name begins with `kubectl-`. To install a plugin, simply move this executable file to anywhere on your PATH.
|
||||
|
||||
{{< note >}}
|
||||
**Note:** Kubernetes does not provide a package manager or anything similar to install or update plugins. It is your responsibility to place the plugin files in the correct location. We recommend that each plugin be stored in its own directory so that installing a plugin distributed as a compressed file is as simple as extracting it to one of the locations specified in the [Plugin loader](#plugin-loader) section.
|
||||
**Note:** Kubernetes does not provide a package manager or anything similar to install or update plugins. It is your responsibility to ensure that plugin executables have a filename that begins with `kubectl-`, and that they are placed somewhere on your PATH.
|
||||
{{< /note >}}
|
||||
|
||||
### Plugin loader
|
||||
### Discovering plugins
|
||||
|
||||
The plugin loader is responsible for searching plugin files in the filesystem locations specified below, and checking if the plugin provides the minimum amount of information required for it to run. Files placed in the right location that don't provide the minimum amount of information, for example an incomplete *plugin.yaml* descriptor, are ignored.
|
||||
`kubectl` provides a command `kubectl plugin list` that searches your PATH for valid plugin executables.
|
||||
Executing this command causes a traversal of all files in your PATH. Any files that are executable, and begin with `kubectl-` will show up *in the order in which they are present in your PATH* in this command's output.
|
||||
A warning will be included for any files beginning with `kubectl-` that are *not* executable.
|
||||
A warning will also be included for any valid plugin files that overlap each other's name.
|
||||
|
||||
#### Search order
|
||||
#### Limitations
|
||||
|
||||
The plugin loader uses the following search order:
|
||||
|
||||
1. `${KUBECTL_PLUGINS_PATH}` If specified, the search stops here.
|
||||
2. `${XDG_DATA_DIRS}/kubectl/plugins`
|
||||
3. `~/.kube/plugins`
|
||||
|
||||
If the `KUBECTL_PLUGINS_PATH` environment variable is present, the loader uses it as the only location to look for plugins.
|
||||
The `KUBECTL_PLUGINS_PATH` environment variable is a list of directories. In Linux and Mac, the list is colon-delimited. In
|
||||
Windows, the list is semicolon-delimited.
|
||||
|
||||
If `KUBECTL_PLUGINS_PATH` is not present, the loader searches these additional locations:
|
||||
|
||||
First, one or more directories specified according to the
|
||||
[XDG System Directory Structure](https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html)
|
||||
specification. Specifically, the loader locates the directories specified by the `XDG_DATA_DIRS` environment variable,
|
||||
and then searches `kubectl/plugins` directory inside of those.
|
||||
If `XDG_DATA_DIRS` is not specified, it defaults to `/usr/local/share:/usr/share`.
|
||||
|
||||
Second, the `plugins` directory under the user's kubeconfig dir. In most cases, this is `~/.kube/plugins`.
|
||||
|
||||
```shell
|
||||
# Loads plugins from both /path/to/dir1 and /path/to/dir2
|
||||
KUBECTL_PLUGINS_PATH=/path/to/dir1:/path/to/dir2 kubectl plugin -h
|
||||
```
|
||||
It is currently not possible to create plugins that overwrite existing `kubectl` commands. For example, creating a plugin `kubectl-version` will cause that plugin to never be executed, as the existing `kubectl version` command will always take precedence over it. Due to this limitation, it is also *not* possible to use plugins to add new subcommands to existing `kubectl` commands. For example, adding a subcommand `kubectl create foo` by naming your plugin `kubectl-create-foo` will cause that plugin to be ignored. Warnings will appear under the output of `kubectl plugin list` for any valid plugins that attempt to do this.
|
||||
|
||||
## Writing kubectl plugins
|
||||
|
||||
You can write a plugin in any programming language or script that allows you to write command-line commands.
|
||||
A plugin does not necessarily need to have a binary component. It could rely entirely on operating system utilities
|
||||
like `echo`, `sed`, or `grep`. Or it could rely on the `kubectl` binary.
|
||||
|
||||
The only strong requirement for a `kubectl` plugin is the `plugin.yaml` descriptor file. This file is responsible for declaring at least the minimum attributes required to register a plugin and must be located under one of the locations specified in the [Search order](#search-order) section.
|
||||
There is no plugin installation or pre-loading required. Plugin executables receive the inherited environment from the `kubectl` binary.
|
||||
A plugin determines which command path it wishes to implement based on its name. For example, a plugin wanting to provide a new command
|
||||
`kubectl foo`, would simply be named `kubectl-foo`, and live somewhere in the user's PATH.
|
||||
|
||||
### The plugin.yaml descriptor
|
||||
|
||||
The descriptor file supports the following attributes:
|
||||
### Example plugin
|
||||
|
||||
```
|
||||
name: "targaryen" # REQUIRED: the plugin command name, to be invoked under 'kubectl'
|
||||
shortDesc: "Dragonized plugin" # REQUIRED: the command short description, for help
|
||||
longDesc: "" # the command long description, for help
|
||||
example: "" # command example(s), for help
|
||||
command: "./dracarys" # REQUIRED: the command, binary, or script to invoke when running the plugin
|
||||
flags: # flags supported by the plugin
|
||||
- name: "heat" # REQUIRED for each flag: flag name
|
||||
shorthand: "h" # short version of the flag name
|
||||
desc: "Fire heat" # REQUIRED for each flag: flag description
|
||||
defValue: "extreme" # default value of the flag
|
||||
tree: # allows the declaration of subcommands
|
||||
- ... # subcommands support the same set of attributes
|
||||
#!/bin/bash
|
||||
|
||||
# optional argument handling
|
||||
if [[ "$1" == "version" ]]
|
||||
then
|
||||
echo "1.0.0"
|
||||
exit 0
|
||||
fi
|
||||
|
||||
# optional argument handling
|
||||
if [[ "$1" == "config" ]]
|
||||
then
|
||||
echo $KUBECONFIG
|
||||
exit 0
|
||||
fi
|
||||
|
||||
echo "I am a plugin named kubectl-foo"
|
||||
```
|
||||
|
||||
The preceding descriptor declares the `kubectl plugin targaryen` plugin, which has one flag named `-h | --heat`.
|
||||
When the plugin is invoked, it calls the `dracarys` binary or script, which is located in the same directory as the descriptor file. The [Accessing runtime attributes](#accessing-runtime-attributes) section describes how the `dracarys` command accesses the flag value and other runtime context.
|
||||
### Using a plugin
|
||||
|
||||
### Recommended directory structure
|
||||
|
||||
It is recommended that each plugin has its own subdirectory in the filesystem, preferably with the same name as the plugin command. The directory must contain the `plugin.yaml` descriptor and any binary, script, asset, or other dependency it might require.
|
||||
|
||||
For example, the directory structure for the `targaryen` plugin could look like this:
|
||||
To use the above plugin, simply make it executable:
|
||||
|
||||
```
|
||||
~/.kube/plugins/
|
||||
└── targaryen
|
||||
├── plugin.yaml
|
||||
└── dracarys
|
||||
sudo chmod +x ./kubectl-foo
|
||||
```
|
||||
|
||||
### Accessing runtime attributes
|
||||
and place it anywhere in your PATH:
|
||||
|
||||
In most use cases, the binary or script file you write to support the plugin must have access to some contextual information provided by the plugin framework. For example, if you declared flags in the descriptor file, your plugin must have access to the user-provided flag values at runtime. The same is true for global flags. The plugin framework is responsible for doing that, so plugin writers don't need to worry about parsing arguments. This also ensures the best level of consistency between plugins and regular `kubectl` commands.
|
||||
```
|
||||
sudo mv ./kubectl-foo /usr/local/bin
|
||||
```
|
||||
|
||||
Plugins have access to runtime context attributes through environment variables. So to access the value provided through a flag, for example, just look for the value of the proper environment variable using the appropriate function call for your binary or script.
|
||||
You may now invoke your plugin as a `kubectl` command:
|
||||
|
||||
The supported environment variables are:
|
||||
```
|
||||
$ kubectl foo
|
||||
I am a plugin named kubectl-foo
|
||||
```
|
||||
|
||||
* `KUBECTL_PLUGINS_CALLER`: The full path to the `kubectl` binary that was used in the current command invocation.
|
||||
As a plugin writer, you don't have to implement logic to authenticate and access the Kubernetes API. Instead, you can invoke `kubectl` to obtain the information you need, through something like `kubectl get --raw=/apis`.
|
||||
All args and flags are passed as-is to the executable:
|
||||
|
||||
* `KUBECTL_PLUGINS_CURRENT_NAMESPACE`: The current namespace that is the context for this call. This is the actual namespace to be used, meaning it was already processed in terms of the precedence between what was provided through the kubeconfig, the `--namespace` global flag, environment variables, and so on.
|
||||
```
|
||||
$ kubectl foo version
|
||||
1.0.0
|
||||
```
|
||||
|
||||
* `KUBECTL_PLUGINS_DESCRIPTOR_*`: One environment variable for every attribute declared in the `plugin.yaml` descriptor.
|
||||
For example, `KUBECTL_PLUGINS_DESCRIPTOR_NAME`, `KUBECTL_PLUGINS_DESCRIPTOR_COMMAND`.
|
||||
All environment variables are also passed as-is to the executable:
|
||||
|
||||
* `KUBECTL_PLUGINS_GLOBAL_FLAG_*`: One environment variable for every global flag supported by `kubectl`.
|
||||
For example, `KUBECTL_PLUGINS_GLOBAL_FLAG_NAMESPACE`, `KUBECTL_PLUGINS_GLOBAL_FLAG_V`.
|
||||
```bash
|
||||
$ export KUBECONFIG=~/.kube/config
|
||||
$ kubectl foo config
|
||||
/home/<user>/.kube/config
|
||||
|
||||
* `KUBECTL_PLUGINS_LOCAL_FLAG_*`: One environment variable for every local flag declared in the `plugin.yaml` descriptor. For example, `KUBECTL_PLUGINS_LOCAL_FLAG_HEAT` in the preceding `targaryen` example.
|
||||
$ KUBECONFIG=/etc/kube/config kubectl foo config
|
||||
/etc/kube/config
|
||||
```
|
||||
|
||||
Additionally, the first argument that is passed to a plugin will always be the full path to the location where it was invoked (`$0` would equal `/usr/local/bin/kubectl-foo` in our example above).
|
||||
|
||||
### Naming a plugin
|
||||
|
||||
As seen in the example above, a plugin determines the command path that it will implement based on its filename. Every sub-command in the command path that a plugin targets, is separated by a dash (`-`).
|
||||
For example, a plugin that wishes to be invoked whenever the command `kubectl foo bar baz` is invoked by the user, would have the filename of `kubectl-foo-bar-baz`.
|
||||
|
||||
#### Flags and argument handling
|
||||
|
||||
Taking our `kubectl-foo-bar-baz` plugin from the above scenario, we further explore additional cases where users invoke our plugin while providing additional flags and arguments.
|
||||
For example, in a situation where a user invokes the command `kubectl foo bar baz arg1 --flag=value arg2`, the plugin mechanism will first try to find the plugin with the longest possible name, which in this case
|
||||
would be `kubectk-foo-bar-baz-arg1`. Upon not finding that plugin, it then treats the last dash-separated value as an argument (`arg1` in this case), and attempts to find the next longest possible name, `kubectl-foo-bar-baz`.
|
||||
Upon finding a plugin with this name, it then invokes that plugin, passing all args and flags after its name to the plugin executable.
|
||||
|
||||
Example:
|
||||
|
||||
```bash
|
||||
# create a plugin
|
||||
$ echo '#!/bin/bash\n\necho "My first command-line argument was $1"' > kubectl-foo-bar-baz
|
||||
$ sudo chmod +x ./kubectl-foo-bar-baz
|
||||
|
||||
# "install" our plugin by placing it on our PATH
|
||||
$ sudo mv ./kubectl-foo-bar-baz /usr/local/bin
|
||||
|
||||
# ensure our plugin is recognized by kubectl
|
||||
$ kubectl plugin list
|
||||
The following kubectl-compatible plugins are available:
|
||||
|
||||
/usr/local/bin/kubectl-foo-bar-baz
|
||||
|
||||
# test that calling our plugin via a "kubectl" command works
|
||||
# even when additional arguments and flags are passed to our
|
||||
# plugin executable by the user.
|
||||
$ kubectl foo bar baz arg1 --meaningless-flag=true
|
||||
My first command-line argument was arg1
|
||||
```
|
||||
|
||||
As you can see, our plugin was found based on the `kubectl` command specified by a user, and all extra arguments and flags were passed as-is to the plugin executable once it was found.
|
||||
|
||||
#### Names with dashes and underscores
|
||||
|
||||
Although the `kubectl` plugin mechanism uses the dashes (`-`) in plugin filenames to determine the sequence of sub-commands that should invoke them, it is still possible to create a plugin
|
||||
command containing dashes in its commandline invocation by using underscores `_` in its filename.
|
||||
|
||||
Example:
|
||||
|
||||
```bash
|
||||
# create a plugin containing an underscore in its filename
|
||||
$ echo '#!/bin/bash\n\necho "I am a plugin with a dash in my name"' > ./kubectl-foo_bar
|
||||
$ sudo chmod +x ./kubectl-foo_bar
|
||||
|
||||
# move the plugin into your PATH
|
||||
$ sudo mv ./kubectl-foo_bar /usr/local/bin
|
||||
|
||||
# our plugin can now be invoked from `kubectl` like so:
|
||||
$ kubectl foo-bar
|
||||
I am a plugin with a dash in my name
|
||||
```
|
||||
|
||||
Note that the introduction of underscores to a plugin filename does not prevent us from having commands such as `kubectl foo_bar`.
|
||||
The command from the above example, can be invoked using either a dash (`-`) or an underscore (`_`):
|
||||
|
||||
```bash
|
||||
# our plugin can be invoked with a dash
|
||||
$ kubectl foo-bar
|
||||
I am a plugin with a dash in my name
|
||||
|
||||
# it can also be inovked using an underscore
|
||||
$ kubectl foo_bar
|
||||
I am a plugin with a dash in my name
|
||||
```
|
||||
|
||||
#### Name conflicts and overshadowing
|
||||
|
||||
It can be possible to have multiple pluins with the same filename in different locations throughout your PATH.
|
||||
For example, given a PATH with the following value: `PATH=/usr/local/bin/plugins:/usr/local/bin/moreplugins`, a copy of plugin `kubectl-foo` could exist in `/usr/local/bin/plugins` and `/usr/local/bin/moreplugins`,
|
||||
such that the output of the `kubectl plugin list` command is:
|
||||
|
||||
```bash
|
||||
$ PATH=/usr/local/bin/plugins:/usr/local/bin/moreplugins kubectl plugin list
|
||||
The following kubectl-compatible plugins are available:
|
||||
|
||||
/usr/local/bin/plugins/kubectl-foo
|
||||
/usr/local/bin/moreplugins/kubectl-foo
|
||||
- warning: /usr/local/bin/moreplugins/kubectl-foo is overshadowed by a similarly named plugin: /usr/local/bin/plugins/kubectl-foo
|
||||
|
||||
error: one plugin warning was found
|
||||
```
|
||||
|
||||
In the above scenario, the warning under `/usr/local/bin/moreplugins/kubectl-foo` tells us that this plugin will never be executed. Instead, the executable that appears first in our PATH, `/usr/local/bin/plugins/kubectl-foo`, willalways be found and executed first by the `kubectl` plugin mechanism.
|
||||
|
||||
A way to resolve this issue is to ensure that the location of the plugin that you wish to use with `kubectl` always comes first in your PATH. For example, if we wanted to always use `/usr/local/bin/moreplugins/kubectl-foo` anytime that the `kubectl` command `kubectl foo` was invoked, we would simply change the value of our PATH to be `PATH=/usr/local/bin/moreplugins:/usr/local/bin/plugins`.
|
||||
|
||||
#### Invocation of the longest executable filename
|
||||
|
||||
There is another kind of overshadowing that can occur with plugin filenames. Given two plugins present in a user's PATH `kubectl-foo-bar` and `kubectl-foo-bar-baz`, the `kubectl` plugin mechanism will always choose the longest possible plugin name for a given user command. Some examples below, clarify this further:
|
||||
|
||||
```bash
|
||||
# for a given kubectl command, the plugin with the longest possible filename will always be preferred
|
||||
$ kubectl foo bar baz
|
||||
Plugin kubectl-foo-bar-baz is executed
|
||||
|
||||
$ kubectl foo bar
|
||||
Plugin kubectl-foo-bar is executed
|
||||
|
||||
$ kubectl foo bar baz buz
|
||||
Plugin kubectl-foo-bar-baz is executed, with "buz" as its first argument
|
||||
|
||||
$ kubectl foo bar buz
|
||||
Plugin kubectl-foo-bar is executed, with "buz" as its first argument
|
||||
```
|
||||
|
||||
This design choice ensures that plugin sub-commands can be implemented across multiple files, if needed, and that these sub-commands can be nested under a "parent" plugin command:
|
||||
|
||||
```bash
|
||||
$ ls ./plugin_command_tree
|
||||
kubectl-parent
|
||||
kubectl-parent-subcommand
|
||||
kubectl-parent-subcommand-subsubcommand
|
||||
```
|
||||
|
||||
### Checking for plugin warnings
|
||||
|
||||
You can use the aforementioned `kubectl plugin list` command to ensure that your plugin is visible by `kubectl`, and verify that there are no warnings preventing it from being called as a `kubectl` command.
|
||||
|
||||
```bash
|
||||
$ kubectl plugin list
|
||||
The following kubectl-compatible plugins are available:
|
||||
|
||||
test/fixtures/pkg/kubectl/plugins/kubectl-foo
|
||||
/usr/local/bin/kubectl-foo
|
||||
- warning: /usr/local/bin/kubectl-foo is overshadowed by a similarly named plugin: test/fixtures/pkg/kubectl/plugins/kubectl-foo
|
||||
plugins/kubectl-invalid
|
||||
- warning: plugins/kubectl-invalid identified as a kubectl plugin, but it is not executable
|
||||
|
||||
error: 2 plugin warnings were found
|
||||
```
|
||||
|
||||
### Using the command line runtime package
|
||||
|
||||
As part of the plugin mechanism update in the v1.12.0 release, an additional set of utilities have been made available to plugin authors. These utilities
|
||||
exist under the [k8s.io/cli-runtime](https://github.com/kubernetes/cli-runtime) repository, and can be used by plugins written in Go to parse and update
|
||||
a user's KUBECONFIG file, obtain REST clients to talk to the API server, and automatically bind flags associated with configuration and printing.
|
||||
|
||||
Plugins *do not* have to be written in Go in order to be recognized as valid plugins by `kubectl`, but they do have to use Go in order to take advantage of
|
||||
the tools and utilities in the CLI Runtime repository.
|
||||
|
||||
See the [Sample CLI Plugin](https://github.com/kubernetes/sample-cli-plugin) for an example usage of the tools provided in the CLI Runtime repo.
|
||||
|
||||
{{% /capture %}}
|
||||
|
||||
{{% capture whatsnext %}}
|
||||
|
||||
* Check the repository for [some more examples](https://github.com/kubernetes/kubernetes/tree/release-1.11/pkg/kubectl/plugins/examples) of plugins.
|
||||
* Check the Sample CLI Plugin repository for [a detailed example](https://github.com/kubernetes/sample-cli-plugin) of a plugin written in Go.
|
||||
* In case of any questions, feel free to reach out to the [CLI SIG team](https://github.com/kubernetes/community/tree/master/sig-cli).
|
||||
* Binary plugins is still an alpha feature, so this is the time to contribute ideas and improvements to the codebase. We're also excited to hear about what you're planning to implement with plugins, so [let us know](https://github.com/kubernetes/community/tree/master/sig-cli)!
|
||||
|
||||
|
||||
@@ -167,18 +167,18 @@ Here CPU utilization dropped to 0, and so HPA autoscaled the number of replicas
|
||||
## Autoscaling on multiple metrics and custom metrics
|
||||
|
||||
You can introduce additional metrics to use when autoscaling the `php-apache` Deployment
|
||||
by making use of the `autoscaling/v2beta1` API version.
|
||||
by making use of the `autoscaling/v2beta2` API version.
|
||||
|
||||
First, get the YAML of your HorizontalPodAutoscaler in the `autoscaling/v2beta1` form:
|
||||
First, get the YAML of your HorizontalPodAutoscaler in the `autoscaling/v2beta2` form:
|
||||
|
||||
```shell
|
||||
$ kubectl get hpa.v2beta1.autoscaling -o yaml > /tmp/hpa-v2.yaml
|
||||
$ kubectl get hpa.v2beta2.autoscaling -o yaml > /tmp/hpa-v2.yaml
|
||||
```
|
||||
|
||||
Open the `/tmp/hpa-v2.yaml` file in an editor, and you should see YAML which looks like this:
|
||||
|
||||
```yaml
|
||||
apiVersion: autoscaling/v2beta1
|
||||
apiVersion: autoscaling/v2beta2
|
||||
kind: HorizontalPodAutoscaler
|
||||
metadata:
|
||||
name: php-apache
|
||||
@@ -194,7 +194,9 @@ spec:
|
||||
- type: Resource
|
||||
resource:
|
||||
name: cpu
|
||||
targetAverageUtilization: 50
|
||||
target:
|
||||
type: Utilization
|
||||
averageUtilization: 50
|
||||
status:
|
||||
observedGeneration: 1
|
||||
lastScaleTime: <some-time>
|
||||
@@ -204,8 +206,9 @@ status:
|
||||
- type: Resource
|
||||
resource:
|
||||
name: cpu
|
||||
currentAverageUtilization: 0
|
||||
currentAverageValue: 0
|
||||
current:
|
||||
averageUtilization: 0
|
||||
averageValue: 0
|
||||
```
|
||||
|
||||
Notice that the `targetCPUUtilizationPercentage` field has been replaced with an array called `metrics`.
|
||||
@@ -215,8 +218,8 @@ the only other supported resource metric is memory. These resources do not chan
|
||||
to cluster, and should always be available, as long as the `metrics.k8s.io` API is available.
|
||||
|
||||
You can also specify resource metrics in terms of direct values, instead of as percentages of the
|
||||
requested value. To do so, use the `targetAverageValue` field instead of the `targetAverageUtilization`
|
||||
field.
|
||||
requested value, by using a `target` type of `AverageValue` instead of `AverageUtilization`, and
|
||||
setting the corresponding `target.averageValue` field instead of the `target.averageUtilization`.
|
||||
|
||||
There are two other types of metrics, both of which are considered *custom metrics*: pod metrics and
|
||||
object metrics. These metrics may have names which are cluster specific, and require a more
|
||||
@@ -224,31 +227,40 @@ advanced cluster monitoring setup.
|
||||
|
||||
The first of these alternative metric types is *pod metrics*. These metrics describe pods, and
|
||||
are averaged together across pods and compared with a target value to determine the replica count.
|
||||
They work much like resource metrics, except that they *only* have the `targetAverageValue` field.
|
||||
They work much like resource metrics, except that they *only* support a `target` type of `AverageValue`.
|
||||
|
||||
Pod metrics are specified using a metric block like this:
|
||||
|
||||
```yaml
|
||||
type: Pods
|
||||
pods:
|
||||
metricName: packets-per-second
|
||||
targetAverageValue: 1k
|
||||
metric:
|
||||
name: packets-per-second
|
||||
target:
|
||||
type: AverageValue
|
||||
averageValue: 1k
|
||||
```
|
||||
|
||||
The second alternative metric type is *object metrics*. These metrics describe a different
|
||||
object in the same namespace, instead of describing pods. Note that the metrics are not
|
||||
fetched from the object -- they simply describe it. Object metrics do not involve averaging,
|
||||
and look like this:
|
||||
The second alternative metric type is *object metrics*. These metrics describe a different
|
||||
object in the same namespace, instead of describing pods. The metrics are not necessarily
|
||||
fetched from the object; they only describe it. Object metrics support `target` types of
|
||||
both `Value` and `AverageValue`. With `Value`, the target is compared directly to the returned
|
||||
metric from the API. With `AverageValue`, the value returned from the custom metrics API is divided
|
||||
by the number of pods before being compared to the target. The following example is the YAML
|
||||
representation of the `requests-per-second` metric.
|
||||
|
||||
```yaml
|
||||
type: Object
|
||||
object:
|
||||
metricName: requests-per-second
|
||||
target:
|
||||
metric:
|
||||
name: requests-per-second
|
||||
describedObject:
|
||||
apiVersion: extensions/v1beta1
|
||||
kind: Ingress
|
||||
name: main-route
|
||||
targetValue: 2k
|
||||
target:
|
||||
type: Value
|
||||
value: 2k
|
||||
```
|
||||
|
||||
If you provide multiple such metric blocks, the HorizontalPodAutoscaler will consider each metric in turn.
|
||||
@@ -275,19 +287,25 @@ spec:
|
||||
- type: Resource
|
||||
resource:
|
||||
name: cpu
|
||||
targetAverageUtilization: 50
|
||||
target:
|
||||
kind: AverageUtilization
|
||||
averageUtilization: 50
|
||||
- type: Pods
|
||||
pods:
|
||||
metricName: packets-per-second
|
||||
metric:
|
||||
name: packets-per-second
|
||||
targetAverageValue: 1k
|
||||
- type: Object
|
||||
object:
|
||||
metricName: requests-per-second
|
||||
target:
|
||||
metric:
|
||||
name: requests-per-second
|
||||
describedObject:
|
||||
apiVersion: extensions/v1beta1
|
||||
kind: Ingress
|
||||
name: main-route
|
||||
targetValue: 10k
|
||||
target:
|
||||
kind: Value
|
||||
value: 10k
|
||||
status:
|
||||
observedGeneration: 1
|
||||
lastScaleTime: <some-time>
|
||||
@@ -297,14 +315,47 @@ status:
|
||||
- type: Resource
|
||||
resource:
|
||||
name: cpu
|
||||
currentAverageUtilization: 0
|
||||
currentAverageValue: 0
|
||||
current:
|
||||
averageUtilization: 0
|
||||
averageValue: 0
|
||||
- type: Object
|
||||
object:
|
||||
metric:
|
||||
name: requests-per-second
|
||||
describedObject:
|
||||
apiVersion: extensions/v1beta1
|
||||
kind: Ingress
|
||||
name: main-route
|
||||
current:
|
||||
value: 10k
|
||||
```
|
||||
|
||||
Then, your HorizontalPodAutoscaler would attempt to ensure that each pod was consuming roughly
|
||||
50% of its requested CPU, serving 1000 packets per second, and that all pods behind the main-route
|
||||
Ingress were serving a total of 10000 requests per second.
|
||||
|
||||
### Autoscaling on more specific metrics
|
||||
|
||||
Many metrics pipelines allow you to describe metrics either by name or by a set of additional
|
||||
descriptors called _labels_. For all non-resource metric types (pod, object, and external,
|
||||
described below), you can specify an additional label selector which is passed to your metric
|
||||
pipeline. For instance, if you collect a metric `http_requests` with the `verb`
|
||||
label, you can specify the following metric block to scale only on GET requests:
|
||||
|
||||
```yaml
|
||||
type: Object
|
||||
object:
|
||||
metric:
|
||||
name: `http_requests`
|
||||
selector: `verb=GET`
|
||||
```
|
||||
|
||||
This selector uses the same syntax as the full Kubernetes label selectors. The monitoring pipeline
|
||||
determines how to collapse multiple series into a single value, if the name and selector
|
||||
match multiple series. The selector is additive, and cannot select metrics
|
||||
that describe objects that are **not** the target object (the target pods in the case of the `Pods`
|
||||
type, and the described object in the case of the `Object` type).
|
||||
|
||||
### Autoscaling on metrics not related to Kubernetes objects
|
||||
|
||||
Applications running on Kubernetes may need to autoscale based on metrics that don't have an obvious
|
||||
@@ -312,12 +363,14 @@ relationship to any object in the Kubernetes cluster, such as metrics describing
|
||||
no direct correlation to Kubernetes namespaces. In Kubernetes 1.10 and later, you can address this use case
|
||||
with *external metrics*.
|
||||
|
||||
Using external metrics requires a certain level of knowledge of your monitoring system, and it requires a cluster
|
||||
monitoring setup similar to one required for using custom metrics. With external metrics, you can autoscale
|
||||
based on any metric available in your monitoring system by providing a `metricName` field in your
|
||||
HorizontalPodAutoscaler manifest. Additionally you can use a `metricSelector` field to limit which
|
||||
metrics' time series you want to use for autoscaling. If multiple time series are matched by `metricSelector`,
|
||||
Using external metrics requires knowledge of your monitoring system; the setup is
|
||||
similar to that required when using custom metrics. External metrics allow you to autoscale your cluster
|
||||
based on any metric available in your monitoring system. Just provide a `metric` block with a
|
||||
`name` and `selector`, as above, and use the `External` metric type instead of `Object`.
|
||||
If multiple time series are matched by the `metricSelector`,
|
||||
the sum of their values is used by the HorizontalPodAutoscaler.
|
||||
External metrics support both the `Value` and `AverageValue` target types, which function exactly the same
|
||||
as when you use the `Object` type.
|
||||
|
||||
For example if your application processes tasks from a hosted queue service, you could add the following
|
||||
section to your HorizontalPodAutoscaler manifest to specify that you need one worker per 30 outstanding tasks.
|
||||
@@ -325,20 +378,21 @@ section to your HorizontalPodAutoscaler manifest to specify that you need one wo
|
||||
```yaml
|
||||
- type: External
|
||||
external:
|
||||
metricName: queue_messages_ready
|
||||
metricSelector:
|
||||
matchLabels:
|
||||
queue: worker_tasks
|
||||
targetAverageValue: 30
|
||||
metric:
|
||||
name: queue_messages_ready
|
||||
selector: "queue=worker_tasks"
|
||||
target:
|
||||
type: AverageValue
|
||||
averageValue: 30
|
||||
```
|
||||
|
||||
If your metric describes work or resources that can be divided between autoscaled pods the `targetAverageValue`
|
||||
field describes how much of that work each pod can handle. Instead of using the `targetAverageValue` field, you could use the
|
||||
`targetValue` to define a desired value of your external metric.
|
||||
When possible, it's preferrable to use the custom metric target types instead of external metrics, since it's
|
||||
easier for cluster administrators to secure the custom metrics API. The external metrics API potentially allows
|
||||
access to any metric, so cluster administrators should take care when exposing it.
|
||||
|
||||
## Appendix: Horizontal Pod Autoscaler Status Conditions
|
||||
|
||||
When using the `autoscaling/v2beta1` form of the HorizontalPodAutoscaler, you will be able to see
|
||||
When using the `autoscaling/v2beta2` form of the HorizontalPodAutoscaler, you will be able to see
|
||||
*status conditions* set by Kubernetes on the HorizontalPodAutoscaler. These status conditions indicate
|
||||
whether or not the HorizontalPodAutoscaler is able to scale, and whether or not it is currently restricted
|
||||
in any way.
|
||||
@@ -378,6 +432,16 @@ was capped by the maximum or minimum of the HorizontalPodAutoscaler. This is an
|
||||
you may wish to raise or lower the minimum or maximum replica count constraints on your
|
||||
HorizontalPodAutoscaler.
|
||||
|
||||
## Appendix: Quantities
|
||||
|
||||
All metrics in the HorizontalPodAutoscaler and metrics APIs are specified using
|
||||
a special whole-number notation known in Kubernetes as a *quantity*. For example,
|
||||
the quantity `10500m` would be written as `10.5` in decimal notation. The metrics APIs
|
||||
will return whole numbers without a suffix when possible, and will generally return
|
||||
quantities in milli-units otherwise. This means you might see your metric value fluctuate
|
||||
between `1` and `1500m`, or `1` and `1.5` when written in decimal notation. See the
|
||||
[glossary entry on quantities](/docs/reference/glossary/quantity.md) for more information.
|
||||
|
||||
## Appendix: Other possible scenarios
|
||||
|
||||
### Creating the autoscaler declaratively
|
||||
|
||||
@@ -55,15 +55,19 @@ or the custom metrics API (for all other metrics).
|
||||
the number of desired replicas.
|
||||
|
||||
Please note that if some of the pod's containers do not have the relevant resource request set,
|
||||
CPU utilization for the pod will not be defined and the autoscaler will not take any action
|
||||
for that metric. See the [autoscaling algorithm design document](https://git.k8s.io/community/contributors/design-proposals/autoscaling/horizontal-pod-autoscaler.md#autoscaling-algorithm) for further
|
||||
details about how the autoscaling algorithm works.
|
||||
CPU utilization for the pod will not be defined and the autoscaler will
|
||||
not take any action for that metric. See the [algorithm
|
||||
details](#algorithm-details) section below for more information about
|
||||
how the autoscaling algorithm works.
|
||||
|
||||
* For per-pod custom metrics, the controller functions similarly to per-pod resource metrics,
|
||||
except that it works with raw values, not utilization values.
|
||||
|
||||
* For object metrics, a single metric is fetched (which describes the object
|
||||
in question), and compared to the target value, to produce a ratio as above.
|
||||
* For object metrics and external metrics, a single metric is fetched, which describes
|
||||
the object in question. This metric is compared compared to the target
|
||||
value, to produce a ratio as above. In the `autoscaling/v2beta2` API
|
||||
version, this value can optionally be divided by the number of pods before the
|
||||
comparison is made.
|
||||
|
||||
The HorizontalPodAutoscaler normally fetches metrics from a series of aggregated APIs (`metrics.k8s.io`,
|
||||
`custom.metrics.k8s.io`, and `external.metrics.k8s.io`). The `metrics.k8s.io` API is usually provided by
|
||||
@@ -83,6 +87,85 @@ by using the scale sub-resource. Scale is an interface that allows you to dynami
|
||||
each of their current states. More details on scale sub-resource can be found
|
||||
[here](https://git.k8s.io/community/contributors/design-proposals/autoscaling/horizontal-pod-autoscaler.md#scale-subresource).
|
||||
|
||||
### Algorithm Details
|
||||
|
||||
From the most basic perspective, the Horizontal Pod Autoscaler controller
|
||||
operates on the ratio between desired metric value and current metric
|
||||
value:
|
||||
|
||||
```
|
||||
desiredReplicas = ceil[currentReplicas * ( currentMetricValue / desiredMetricValue )]
|
||||
```
|
||||
|
||||
For example, if the current metric value is `200m`, and the desired value
|
||||
is `100m`, the number of replicas will be doubled, since `200.0 / 100.0 ==
|
||||
2.0` If the the current value is instead `50m`, we'll halve the number of
|
||||
replicas, since `50.0 / 100.0 == 0.5`. We'll skip scaling if the ratio is
|
||||
sufficiently close to 1.0 (within a globally-configurable tolerance, from
|
||||
the `--horizontal-pod-autoscaler-tolerance` flag, which defaults to 0.1).
|
||||
|
||||
When a `targetAverageValue` or `targetAverageUtilization` is specified,
|
||||
the `currentMetricValue` is computed by taking the average of the given
|
||||
metric across all Pods in the HorizontalPodAutoscaler's scale target.
|
||||
Before checking the tolerance and deciding on the final values, we take
|
||||
pod readiness and missing metrics into consideration, however.
|
||||
|
||||
All Pods with a deletion timestamp set (i.e. Pods in the process of being
|
||||
shut down) and all failed Pods are discarded.
|
||||
|
||||
If a particular Pod is missing metrics, it is set aside for later; Pods
|
||||
with missing metrics will be used to adjust the final scaling amount.
|
||||
|
||||
When scaling on CPU, if any pod has yet to become ready (i.e. it's still
|
||||
initializing) *or* the most recent metric point for the pod was before it
|
||||
became ready, that pod is set aside as well.
|
||||
|
||||
Due to technical constraints, the HorizontalPodAutoscaler controller
|
||||
cannot exactly determine the first time a pod becomes ready when
|
||||
determinining whether to set aside certain CPU metrics. Instead, it
|
||||
considers a Pod "not yet ready" if it's unready and transitioned to
|
||||
unready within a short, configurable window of time since it started.
|
||||
This value is configured with the `--horizontal-pod-autoscaler-initial-readiness-delay` flag, and its default is 30
|
||||
seconds. Once a pod has become ready, it considers any transition to
|
||||
ready to be the first if it occurred within a longer, configurable time
|
||||
since it started. This value is configured with the `--horizontal-pod-autoscaler-cpu-initialization-period` flag, and its
|
||||
default is 5 minutes.
|
||||
|
||||
The `currentMetricValue / desiredMetricValue` base scale ratio is then
|
||||
calculated using the remaining pods not set aside or discarded from above.
|
||||
|
||||
If there were any missing metrics, we recompute the average more
|
||||
conservatively, assuming those pods were consuming 100% of the desired
|
||||
value in case of a scale down, and 0% in case of a scale up. This dampens
|
||||
the magnitude of any potential scale.
|
||||
|
||||
Futhermore, if any not-yet-ready pods were present, and we would have
|
||||
scaled up without factoring in missing metrics or not-yet-ready pods, we
|
||||
conservatively assume the non-yet-ready pods are consuming 0% of the
|
||||
desired metric, further dampening the magnitude of a scale up.
|
||||
|
||||
After factoring in the not-yet-ready pods and missing metrics, we
|
||||
recalculate the usage ratio. If the new ratio reverses the scale
|
||||
direction, or is within the tolerance, we skip scaling. Otherwise, we use
|
||||
the new ratio to scale.
|
||||
|
||||
Note that the *original* value for the average utilization is reported
|
||||
back via the HorizontalPodAutoscaler status, without factoring in the
|
||||
not-yet-ready pods or missing metrics, even when the new usage ratio is
|
||||
used.
|
||||
|
||||
If multiple metrics are specified in a HorizontalPodAutoscaler, this
|
||||
calculation is done for each metric, and then the largest of the desired
|
||||
replica counts is chosen. If any of those metrics cannot be converted
|
||||
into a desired replica count (e.g. due to an error fetching the metrics
|
||||
from the metrics APIs), scaling is skipped.
|
||||
|
||||
Finally, just before HPA scales the target, the scale reccomendation is recorded. The
|
||||
controller considers all reccomendations within a configurable window choosing the
|
||||
highest recommendation from within that window. This value can be configured using the `--horizontal-pod-autoscaler-downscale-stabilization-window` flag, which defaults to 5 minutes.
|
||||
This means that scaledowns will occur gradually, smothing out the impact of rapidly
|
||||
fluctuating metric values.
|
||||
|
||||
## API Object
|
||||
|
||||
The Horizontal Pod Autoscaler is an API resource in the Kubernetes `autoscaling` API group.
|
||||
@@ -90,7 +173,7 @@ The current stable version, which only includes support for CPU autoscaling,
|
||||
can be found in the `autoscaling/v1` API version.
|
||||
|
||||
The beta version, which includes support for scaling on memory and custom metrics,
|
||||
can be found in `autoscaling/v2beta1`. The new fields introduced in `autoscaling/v2beta1`
|
||||
can be found in `autoscaling/v2beta2`. The new fields introduced in `autoscaling/v2beta2`
|
||||
are preserved as annotations when working with `autoscaling/v1`.
|
||||
|
||||
More details about the API object can be found at
|
||||
@@ -131,16 +214,14 @@ dynamic nature of the metrics evaluated. This is sometimes referred to as *thras
|
||||
Starting from v1.6, a cluster operator can mitigate this problem by tuning
|
||||
the global HPA settings exposed as flags for the `kube-controller-manager` component:
|
||||
|
||||
Starting from v1.12, a new algorithmic update removes the need for the
|
||||
upscale delay.
|
||||
|
||||
- `--horizontal-pod-autoscaler-downscale-delay`: The value for this option is a
|
||||
duration that specifies how long the autoscaler has to wait before another
|
||||
downscale operation can be performed after the current one has completed.
|
||||
The default value is 5 minutes (`5m0s`).
|
||||
|
||||
- `--horizontal-pod-autoscaler-upscale-delay`: The value for this option is a
|
||||
duration that specifies how long the autoscaler has to wait before another
|
||||
upscale operation can be performed after the current one has completed.
|
||||
The default value is 3 minutes (`3m0s`).
|
||||
|
||||
{{< note >}}
|
||||
**Note**: When tuning these parameter values, a cluster operator should be aware of
|
||||
the possible consequences. If the delay (cooldown) value is set too long, there
|
||||
@@ -151,7 +232,7 @@ may keep thrashing as usual.
|
||||
|
||||
## Support for multiple metrics
|
||||
|
||||
Kubernetes 1.6 adds support for scaling based on multiple metrics. You can use the `autoscaling/v2beta1` API
|
||||
Kubernetes 1.6 adds support for scaling based on multiple metrics. You can use the `autoscaling/v2beta2` API
|
||||
version to specify multiple metrics for the Horizontal Pod Autoscaler to scale on. Then, the Horizontal Pod
|
||||
Autoscaler controller will evaluate each metric, and propose a new scale based on that metric. The largest of the
|
||||
proposed scales will be used as the new scale.
|
||||
@@ -164,7 +245,7 @@ custom metrics is still available, these metrics will not be available for use b
|
||||
annotations for specifying which custom metrics to scale on are no longer honored by the Horizontal Pod Autoscaler controller.
|
||||
|
||||
Kubernetes 1.6 adds support for making use of custom metrics in the Horizontal Pod Autoscaler.
|
||||
You can add custom metrics for the Horizontal Pod Autoscaler to use in the `autoscaling/v2beta1` API.
|
||||
You can add custom metrics for the Horizontal Pod Autoscaler to use in the `autoscaling/v2beta2` API.
|
||||
Kubernetes then queries the new custom metrics API to fetch the values of the appropriate custom metrics.
|
||||
|
||||
See [Support for metrics APIs](#support-for-metrics-APIs) for the requirements.
|
||||
|
||||
Reference in New Issue
Block a user