Overall cleanup for kubeadm setup guide. (#8981)
* Overall cleanup for kubeadm setup guide. * Add sonobuoy verification next step * Partial copyedits Hit a place where we also have formatting issues, plus a TODO (removed bc these changes go live as soon as merged). More work to do, but this should help the bottleneck for now. * Address comments from reviewers * Copy edits, fiddly bits, and clearer warnings Incorporated feedback from @mistyhacks, fixed many nits, reorganized some **Note:** content more sensibly. * Revised title per feedback
This commit is contained in:
Timothy St. Clair
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k8s-ci-robot
parent
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commit
c09c48b2dc
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---
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title: "Administration with kubeadm"
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weight: 10
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---
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@@ -0,0 +1,290 @@
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---
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reviewers:
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- pipejakob
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- luxas
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- roberthbailey
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- jbeda
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title: Upgrading kubeadm clusters from 1.7 to 1.8
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content_template: templates/task
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---
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{{% capture overview %}}
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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`.
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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.
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{{% /capture %}}
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{{% capture prerequisites %}}
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Before proceeding:
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- You need to have a functional `kubeadm` Kubernetes cluster running version 1.7.0 or higher in order to use the process described here.
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- Make sure you read the [release notes](https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG.md#v180-beta1) carefully.
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- 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.
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- 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.
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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.
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{{% /capture %}}
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{{% capture steps %}}
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## Upgrading your control plane
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You have to carry out the following steps by executing these commands on your master node:
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1. Install the most recent version of `kubeadm` using `curl` like so:
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{{< caution >}}
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```shell
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export VERSION=$(curl -sSL https://dl.k8s.io/release/stable.txt) # or manually specify a released Kubernetes version
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export ARCH=amd64 # or: arm, arm64, ppc64le, s390x
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curl -sSL https://dl.k8s.io/release/${VERSION}/bin/linux/${ARCH}/kubeadm > /usr/bin/kubeadm
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chmod a+rx /usr/bin/kubeadm
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```
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**Caution:** Upgrading the `kubeadm` package on your system prior to
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upgrading the control plane causes a failed upgrade. Even though
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`kubeadm` is shipped in the Kubernetes repositories, it's important
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to install `kubeadm` manually. The kubeadm team is working on fixing
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this limitation.
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{{< /caution >}}
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Verify that this download of kubeadm works, and has the expected version:
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```shell
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kubeadm version
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```
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2. If this the first time you use `kubeadm upgrade`, in order to preserve the configuration for future upgrades, do:
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Note that for below you will need to recall what CLI args you passed to `kubeadm init` the first time.
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If you used flags, do:
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```shell
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kubeadm config upload from-flags [flags]
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```
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Where `flags` can be empty.
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If you used a config file, do:
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```shell
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kubeadm config upload from-file --config [config]
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```
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Where the `config` is mandatory.
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3. On the master node, run the following:
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```shell
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kubeadm upgrade plan
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```
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You should see output similar to this:
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```shell
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[preflight] Running pre-flight checks
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[upgrade] Making sure the cluster is healthy:
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[upgrade/health] Checking API Server health: Healthy
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[upgrade/health] Checking Node health: All Nodes are healthy
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[upgrade/health] Checking Static Pod manifests exists on disk: All manifests exist on disk
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[upgrade/config] Making sure the configuration is correct:
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[upgrade/config] Reading configuration from the cluster...
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[upgrade/config] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml'
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[upgrade] Fetching available versions to upgrade to:
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[upgrade/versions] Cluster version: v1.7.1
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[upgrade/versions] kubeadm version: v1.8.0
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[upgrade/versions] Latest stable version: v1.8.0
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[upgrade/versions] Latest version in the v1.7 series: v1.7.6
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Components that must be upgraded manually after you've upgraded the control plane with 'kubeadm upgrade apply':
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COMPONENT CURRENT AVAILABLE
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Kubelet 1 x v1.7.1 v1.7.6
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Upgrade to the latest version in the v1.7 series:
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COMPONENT CURRENT AVAILABLE
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API Server v1.7.1 v1.7.6
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Controller Manager v1.7.1 v1.7.6
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Scheduler v1.7.1 v1.7.6
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Kube Proxy v1.7.1 v1.7.6
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Kube DNS 1.14.4 1.14.4
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You can now apply the upgrade by executing the following command:
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kubeadm upgrade apply v1.7.6
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_____________________________________________________________________
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Components that must be upgraded manually after you've upgraded the control plane with 'kubeadm upgrade apply':
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COMPONENT CURRENT AVAILABLE
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Kubelet 1 x v1.7.1 v1.8.0
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Upgrade to the latest stable version:
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COMPONENT CURRENT AVAILABLE
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API Server v1.7.1 v1.8.0
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Controller Manager v1.7.1 v1.8.0
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Scheduler v1.7.1 v1.8.0
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Kube Proxy v1.7.1 v1.8.0
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Kube DNS 1.14.4 1.14.4
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You can now apply the upgrade by executing the following command:
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kubeadm upgrade apply v1.8.0
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Note: Before you do can perform this upgrade, you have to update kubeadm to v1.8.0
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_____________________________________________________________________
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```
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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.
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4. Pick a version to upgrade to and run, for example, `kubeadm upgrade apply` as follows:
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```shell
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kubeadm upgrade apply v1.8.0
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```
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You should see output similar to this:
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```shell
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[preflight] Running pre-flight checks
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[upgrade] Making sure the cluster is healthy:
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[upgrade/health] Checking API Server health: Healthy
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[upgrade/health] Checking Node health: All Nodes are healthy
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[upgrade/health] Checking Static Pod manifests exists on disk: All manifests exist on disk
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[upgrade/config] Making sure the configuration is correct:
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[upgrade/config] Reading configuration from the cluster...
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[upgrade/config] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml'
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[upgrade/version] You have chosen to upgrade to version "v1.8.0"
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[upgrade/versions] Cluster version: v1.7.1
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[upgrade/versions] kubeadm version: v1.8.0
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[upgrade/prepull] Will prepull images for components [kube-apiserver kube-controller-manager kube-scheduler]
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[upgrade/prepull] Prepulling image for component kube-scheduler.
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[upgrade/prepull] Prepulling image for component kube-apiserver.
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[upgrade/prepull] Prepulling image for component kube-controller-manager.
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[apiclient] Found 0 Pods for label selector k8s-app=upgrade-prepull-kube-scheduler
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[apiclient] Found 1 Pods for label selector k8s-app=upgrade-prepull-kube-scheduler
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[apiclient] Found 1 Pods for label selector k8s-app=upgrade-prepull-kube-apiserver
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[apiclient] Found 1 Pods for label selector k8s-app=upgrade-prepull-kube-controller-manager
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[upgrade/prepull] Prepulled image for component kube-apiserver.
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[upgrade/prepull] Prepulled image for component kube-controller-manager.
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[upgrade/prepull] Prepulled image for component kube-scheduler.
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[upgrade/prepull] Successfully prepulled the images for all the control plane components
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[upgrade/apply] Upgrading your Static Pod-hosted control plane to version "v1.8.0"...
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[upgrade/staticpods] Writing upgraded Static Pod manifests to "/etc/kubernetes/tmp/kubeadm-upgraded-manifests432902769"
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[controlplane] Wrote Static Pod manifest for component kube-apiserver to "/etc/kubernetes/tmp/kubeadm-upgraded-manifests432902769/kube-apiserver.yaml"
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[controlplane] Wrote Static Pod manifest for component kube-controller-manager to "/etc/kubernetes/tmp/kubeadm-upgraded-manifests432902769/kube-controller-manager.yaml"
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[controlplane] Wrote Static Pod manifest for component kube-scheduler to "/etc/kubernetes/tmp/kubeadm-upgraded-manifests432902769/kube-scheduler.yaml"
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[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"
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[upgrade/staticpods] Waiting for the kubelet to restart the component
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[apiclient] Found 1 Pods for label selector component=kube-apiserver
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[upgrade/staticpods] Component "kube-apiserver" upgraded successfully!
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[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"
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[upgrade/staticpods] Waiting for the kubelet to restart the component
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[apiclient] Found 1 Pods for label selector component=kube-controller-manager
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[upgrade/staticpods] Component "kube-controller-manager" upgraded successfully!
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[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"
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[upgrade/staticpods] Waiting for the kubelet to restart the component
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[apiclient] Found 1 Pods for label selector component=kube-scheduler
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[upgrade/staticpods] Component "kube-scheduler" upgraded successfully!
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[uploadconfig] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
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[bootstraptoken] Configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
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[bootstraptoken] Configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
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[addons] Applied essential addon: kube-dns
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[addons] Applied essential addon: kube-proxy
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[upgrade/successful] SUCCESS! Your cluster was upgraded to "v1.8.0". Enjoy!
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[upgrade/kubelet] Now that your control plane is upgraded, please proceed with upgrading your kubelets in turn.
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```
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`kubeadm upgrade apply` does the following:
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- It checks that your cluster is in an upgradeable state, that is:
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- The API Server is reachable,
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- All nodes are in the `Ready` state, and
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- The control plane is healthy
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- It enforces the version skew policies.
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- It makes sure the control plane images are available or available to pull to the machine.
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- It upgrades the control plane components or rollbacks if any of them fails to come up.
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- It applies the new `kube-dns` and `kube-proxy` manifests and enforces that all necessary RBAC rules are created.
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5. Manually upgrade your Software Defined Network (SDN).
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Your Container Network Interface (CNI) provider might have its own upgrade instructions to follow now.
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Check the [addons](/docs/concepts/cluster-administration/addons/) page to
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find your CNI provider and see if there are additional upgrade steps
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necessary.
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6. Add RBAC permissions for automated certificate rotation. In the future, kubeadm will perform this step automatically:
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```shell
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kubectl create clusterrolebinding kubeadm:node-autoapprove-certificate-rotation --clusterrole=system:certificates.k8s.io:certificatesigningrequests:selfnodeclient --group=system:nodes
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```
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## Upgrading your master and node packages
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For each host (referred to as `$HOST` below) in your cluster, upgrade `kubelet` by executing the following commands:
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1. Prepare the host for maintenance, marking it unschedulable and evicting the workload:
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```shell
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kubectl drain $HOST --ignore-daemonsets
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```
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When running this command against the master host, this error is expected and can be safely ignored (since there are static pods running on the master):
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```shell
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node "master" already cordoned
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error: pods not managed by ReplicationController, ReplicaSet, Job, DaemonSet or StatefulSet (use --force to override): etcd-kubeadm, kube-apiserver-kubeadm, kube-controller-manager-kubeadm, kube-scheduler-kubeadm
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```
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2. Upgrade the Kubernetes package versions on the `$HOST` node by using a Linux distribution-specific package manager:
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If the host is running a Debian-based distro such as Ubuntu, run:
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```shell
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apt-get update
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apt-get upgrade
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```
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If the host is running CentOS or the like, run:
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```shell
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yum update
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```
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Now the new version of the `kubelet` should be running on the host. Verify this using the following command on `$HOST`:
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```shell
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systemctl status kubelet
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```
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3. Bring the host back online by marking it schedulable:
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```shell
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kubectl uncordon $HOST
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```
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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):
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```shell
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kubectl get nodes
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```
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If the `STATUS` column of the above command shows `Ready` for all of your hosts, you are done.
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## Recovering from a bad state
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If `kubeadm upgrade` somehow fails and fails to roll back, due to an unexpected shutdown during execution for instance,
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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.
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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.
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{{% /capture %}}
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@@ -0,0 +1,264 @@
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---
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reviewers:
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- pipejakob
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- luxas
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- roberthbailey
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- jbeda
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title: Upgrading/downgrading kubeadm clusters between v1.8 to v1.9
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content_template: templates/task
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---
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{{% capture overview %}}
|
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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`.
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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.
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{{% /capture %}}
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{{% capture prerequisites %}}
|
||||
|
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Before proceeding:
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|
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- 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.
|
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- Make sure you read the [release notes](https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG-1.9.md) carefully.
|
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- `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.
|
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- 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.
|
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|
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{{< 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 %}}
|
||||
|
||||
|
||||
@@ -0,0 +1,136 @@
|
||||
---
|
||||
reviewers:
|
||||
- jamiehannaford
|
||||
- luxas
|
||||
- timothysc
|
||||
- jbeda
|
||||
title: Upgrading kubeadm HA clusters from 1.9.x to 1.9.y
|
||||
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`.
|
||||
|
||||
{{% /capture %}}
|
||||
|
||||
{{% capture prerequisites %}}
|
||||
|
||||
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.
|
||||
|
||||
{{% /capture %}}
|
||||
|
||||
{{% capture steps %}}
|
||||
|
||||
## Preparation
|
||||
|
||||
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:
|
||||
|
||||
```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
|
||||
```
|
||||
|
||||
Copy this file to `/tmp` on your primary master if necessary. Run this command for checking prerequisites and determining the versions you will receive:
|
||||
|
||||
```shell
|
||||
/tmp/kubeadm upgrade plan
|
||||
```
|
||||
|
||||
If the prerequisites are met you'll get a summary of the software versions kubeadm will upgrade to, like this:
|
||||
|
||||
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
|
||||
|
||||
{{< 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 >}}
|
||||
|
||||
## Upgrading your control plane
|
||||
|
||||
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:
|
||||
|
||||
```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
|
||||
```
|
||||
|
||||
Now the upgrade process can start. Use the target version determined in the preparation step and run the following command (press “y” when prompted):
|
||||
|
||||
```shell
|
||||
/tmp/kubeadm upgrade apply v<YOUR-CHOSEN-VERSION-HERE>
|
||||
```
|
||||
|
||||
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:
|
||||
|
||||
```shell
|
||||
# use your distro's package manager, e.g. 'yum' on RH-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>
|
||||
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.
|
||||
|
||||
Now the new version of the `kubelet` should be running on the host. Verify this using the following command on the respective host:
|
||||
|
||||
```shell
|
||||
systemctl status kubelet
|
||||
```
|
||||
|
||||
Verify that the upgraded node is available again by executing the following from wherever you run `kubectl` commands:
|
||||
|
||||
```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 something goes wrong
|
||||
|
||||
If the upgrade fails the situation afterwards depends on the phase in which things went wrong:
|
||||
|
||||
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.
|
||||
|
||||
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.
|
||||
|
||||
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.
|
||||
|
||||
{{% /capture %}}
|
||||
|
||||
|
||||
Reference in New Issue
Block a user