whentimeslows/website
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Official 1.17 Release Docs (#18011)

Browse Source 
* feat: graduate TaintNodesByCondition to GA (#17073)

* Promote StartupProbe to beta (enabled by default). (#17164)

* Watch bookmarks to GA (#17026)

* feat: graduate ScheduleDaemonSetPods to GA (#17350)

* Update Docker installation instructions (#17405)

* Use exact version numbers for installing Docker in Ubuntu (#17428)

* Move CSIMigration and CSIMigrationGCE to Beta in Kubernetes v1.17 (#17478)

* Promote NodeLease feature to GA (#17189)

* Update docs for csi topology ga (#17408)

* Update RunAsUsername to beta (#17460)

* doc:Update RunAsUsername to beta

* doc: update samples - kubernetes.io/os is no longer beta

* Updating based on review feedback

* Promote Node-specific volume limits to GA (#17432)

* Promote PodShareProcessNamespace to stable (#17192)

* Promote PodShareProcessNamespace to stable

* Add for_k8s_version to feature-state label

Co-Authored-By: Tim Bannister <tim@scalefactory.com>

* Readd version-check to shareProcessNamespace task

* Update service load balancer finalizer doc for GA (#17438)

* Update Topology Manager docs (#17451)

* Added information on how device plugins can take advantage
of Topology Manager
* Updated the Topology Manager documentation to include additionalinformation and update some out of date sections

* Fix broken Topology Manager link (#17746)

Part of What's Next Device Plugin section

* Update CRD defaulting docs for GA (#17450)

* Add documentation for VolumeSnapshot Beta (#17233)

* Updating EndpointSlice documentation for beta release in 1.17 (#17411)

* (docs/dualstack): v1.17 updates (#17457)

* Add placehold doc updates for dualstack in 1.17

Signed-off-by: Lachlan Evenson <lachlan.evenson@microsoft.com>

* Add Downward API and /etc/hosts Pod IP validation

Signed-off-by: Lachlan Evenson <lachlan.evenson@microsoft.com>

* remove addressed known issue via k/k pr 85246

Signed-off-by: Lachlan Evenson <lachlan.evenson@microsoft.com>

* Remove known issue and add flag as part of k/k 79993

Signed-off-by: Lachlan Evenson <lachlan.evenson@microsoft.com>

* remove follow up placeholders

Signed-off-by: Lachlan Evenson <lachlan.evenson@microsoft.com>

* Update verbiage

Signed-off-by: Lachlan Evenson <lachlan.evenson@microsoft.com>

* Make IP addressing consistent throughout the task

Signed-off-by: Lachlan Evenson <lachlan.evenson@microsoft.com>

* Update to status.podIPs

Signed-off-by: Lachlan Evenson <lachlan.evenson@microsoft.com>

* Update content/en/docs/tasks/network/validate-dual-stack.md

Use set instead of env

Co-Authored-By: Khaled Henidak (Kal) <khnidk@outlook.com>

* add topology.kubernetes.io/zone, topology.kubernetes.io/region and node.kubernetes.io/instance-type labels to docs (#17498)

Signed-off-by: Andrew Sy Kim <kiman@vmware.com>

* Service topology alpha documentation (#17459)

* Update list of feature flags for in-tree plugins migrated to CSI (#17533)

Signed-off-by: Deep Debroy <ddebroy@docker.com>

* Update Node concept for TaintNodesByCondition going GA (#17577)

* feat: graduate ResourceQuotaScopeSelectors to GA in 1.17 (#17554)

* kubeadm: update the upgrade documentation for 1.17 (#17587)

* doc: Simplify Windows deployments with RuntimeClass (#16697)

* doc: Simplify Windows deployments with RuntimeClass

* Updating on review feedback

* doc: Adding windows-build label from enhancement 1301

* update doc for kubelet option --reserved-cpus (#17648)

* feat: update TaintNodesByCondition in feature gates table (#17377)

* Update docs for v1 resource quota configuration (#17547)

* AdmissionConfiguration v1 (#17548)

* Update WebhookAdmissionConfiguration examples (#17549)

* Update AWS EBS Migration Feature state (#16126)

* Add resource version section to api-concepts documentation (#16910)

* Add Resource Version semantics section to api concepts

* Clarify risks of going back in time, add details about compaction and watch cache sizes

* Apply suggestions from liggitt

Co-Authored-By: Jordan Liggitt <jordan@liggitt.net>

* remove pesudocode, apply feedback

* Fix typo

* Clarify equality rules

* Cleanup kubectl generators docs (#17609)

* Write ReplicationController without a space

* Drop mentioning unsupported cluster versions

* Fix capitalization for “API group”

* Tweak wording

* Avoid using deprecated generator in example

* add Antrea description in dev-1.17 (#17919)

* Promote VolumeSubpathEnvExpansion to GA

* Reference Documentation for the Kubernetes API for 1.17 (#18019)

* Update feature-gates.md (#18033)

* Reference Documentation for kubectl Commands for 1.17 (#18017)

* Update for v1.17 (#18034)

* Update config.toml(release-1.17) for 1.17 (#18031)
This commit is contained in:
Damini Satya
2019-12-10 05:41:29 +05:30
committed by Kubernetes Prow Robot
parent cf925bb688
commit dff2f7b960
63 changed files with 62955 additions and 443 deletions
Download Patch File Download Diff File Expand all files Collapse all files
content/en/docs/concepts/storage/volume-snapshots.md
+80 -66
View File
@@ -1,9 +1,11 @@
---
reviewers:
- jsafrane
- saad-ali
- thockin
- msau42
- jingxu97
- xing-yang
- yuxiangqian
title: Volume Snapshots
content_template: templates/concept
weight: 20
@@ -11,8 +13,8 @@ weight: 20
{{% capture overview %}}
{{< feature-state for_k8s_version="v1.12" state="alpha" >}}
This document describes the current state of `VolumeSnapshots` in Kubernetes. Familiarity with [persistent volumes](/docs/concepts/storage/persistent-volumes/) is suggested.
{{< feature-state for_k8s_version="1.17" state="beta" >}}
In Kubernetes, a _VolumeSnapshot_ represents a snapshot of a volume on a storage system. This document assumes that you are already familiar with Kubernetes [persistent volumes](/docs/concepts/storage/persistent-volumes/).
{{% /capture %}}
@@ -27,18 +29,15 @@ A `VolumeSnapshotContent` is a snapshot taken from a volume in the cluster that
A `VolumeSnapshot` is a request for snapshot of a volume by a user. It is similar to a PersistentVolumeClaim.
While `VolumeSnapshots` allow a user to consume abstract storage resources, cluster administrators
need to be able to offer a variety of `VolumeSnapshotContents` without exposing
users to the details of how those volume snapshots should be provisioned. For these needs
there is the `VolumeSnapshotClass` resource.
`VolumeSnapshotClass` allows you to specify different attributes belonging to a `VolumeSnapshot`. These attibutes may differ among snapshots taken from the same volume on the storage system and therefore cannot be expressed by using the same `StorageClass` of a `PersistentVolumeClaim`.
Users need to be aware of the following when using this feature:
* API Objects `VolumeSnapshot`, `VolumeSnapshotContent`, and `VolumeSnapshotClass` are CRDs, not part of the core API.
* API Objects `VolumeSnapshot`, `VolumeSnapshotContent`, and `VolumeSnapshotClass` are {{< glossary_tooltip term_id="CustomResourceDefinition" text="CRDs" >}}, not part of the core API.
* `VolumeSnapshot` support is only available for CSI drivers.
* As part of the deployment process, the Kubernetes team provides a sidecar helper container for the snapshot controller called `external-snapshotter`. It watches `VolumeSnapshot` objects and triggers `CreateSnapshot` and `DeleteSnapshot` operations against a CSI endpoint.
* CSI drivers may or may not have implemented the volume snapshot functionality. The CSI drivers that have provided support for volume snapshot will likely use `external-snapshotter`.
* The CSI drivers that support volume snapshot will automatically install CRDs defined for the volume snapshots.
* As part of the deployment process in the beta version of `VolumeSnapshot`, the Kubernetes team provides a snapshot controller to be deployed into the control plane, and a sidecar helper container called csi-snapshotter to be deployed together with the CSI driver. The snapshot controller watches `VolumeSnapshot` and `VolumeSnapshotContent` objects and is responsible for the creation and deletion of `VolumeSnapshotContent` object in dynamic provisioning. The sidecar csi-snapshotter watches `VolumeSnapshotContent` objects and triggers `CreateSnapshot` and `DeleteSnapshot` operations against a CSI endpoint.
* CSI drivers may or may not have implemented the volume snapshot functionality. The CSI drivers that have provided support for volume snapshot will likely use the csi-snapshotter. See [CSI Driver documentation](https://kubernetes-csi.github.io/docs/) for details.
* The CRDs and snapshot controller installations are the responsibility of the Kubernetes distribution.
## Lifecycle of a volume snapshot and volume snapshot content
@@ -46,89 +45,104 @@ Users need to be aware of the following when using this feature:
### Provisioning Volume Snapshot
There are two ways snapshots may be provisioned: statically or dynamically.
There are two ways snapshots may be provisioned: pre-provisioned or dynamically provisioned.
#### Static
A cluster administrator creates a number of `VolumeSnapshotContents`. They carry the details of the real storage which is available for use by cluster users. They exist in the Kubernetes API and are available for consumption.
#### Pre-provisioned {#static}
A cluster administrator creates a number of `VolumeSnapshotContents`. They carry the details of the real volume snapshot on the storage system which is available for use by cluster users. They exist in the Kubernetes API and are available for consumption.
#### Dynamic
When none of the static `VolumeSnapshotContents` the administrator created matches a user's `VolumeSnapshot`,
the cluster may try to dynamically provision a volume snapshot specially for the `VolumeSnapshot` object.
This provisioning is based on `VolumeSnapshotClasses`: the `VolumeSnapshot` must request a
[volume snapshot class](/docs/concepts/storage/volume-snapshot-classes/) and
the administrator must have created and configured that class in order for dynamic
provisioning to occur.
Instead of using a pre-existing snapshot, you can request that a snapshot to be dynamically taken from a PersistentVolumeClaim. The [VolumeSnapshotClass](/docs/concepts/storage/volume-snapshot-classes/) specifies storage provider-specific parameters to use when taking a snapshot.
### Binding
A user creates, or has already created in the case of dynamic provisioning, a `VolumeSnapshot` with a specific amount of storage requested and with certain access modes. A control loop watches for new VolumeSnapshots, finds a matching VolumeSnapshotContent (if possible), and binds them together. If a VolumeSnapshotContent was dynamically provisioned for a new VolumeSnapshot, the loop will always bind that VolumeSnapshotContent to the VolumeSnapshot. Once bound, `VolumeSnapshot` binds are exclusive, regardless of how they were bound. A VolumeSnapshot to VolumeSnapshotContent binding is a one-to-one mapping.
The snapshot controller handles the binding of a `VolumeSnapshot` object with an appropriate `VolumeSnapshotContent` object, in both pre-provisioned and dynamically provisioned scenarios. The binding is a one-to-one mapping.
VolumeSnapshots will remain unbound indefinitely if a matching VolumeSnapshotContent does not exist. VolumeSnapshots will be bound as matching VolumeSnapshotContents become available.
In the case of pre-provisioned binding, the VolumeSnapshot will remain unbound until the requested VolumeSnapshotContent object is created.
### Persistent Volume Claim in Use Protection
### Persistent Volume Claim as Snapshot Source Protection
The purpose of the Persistent Volume Claim Object in Use Protection feature is to ensure that in-use PVC API objects are not removed from the system (as this may result in data loss).
The purpose of this protection is to ensure that in-use PersistentVolumeClaim API objects are not removed from the system while a snapshot is being taken from it (as this may result in data loss).
If a PVC is in active use by a snapshot as a source to create the snapshot, the PVC is in-use. If a user deletes a PVC API object in active use as a snapshot source, the PVC object is not removed immediately. Instead, removal of the PVC object is postponed until the PVC is no longer actively used by any snapshots. A PVC is no longer used as a snapshot source when `ReadyToUse` of the snapshot `Status` becomes `true`.
While a snapshot is being taken of a PersistentVolumeClaim, that PersistentVolumeClaim is in-use. If you delete a PersistentVolumeClaim API object in active use as a snapshot source, the PersistentVolumeClaim object is not removed immediately. Instead, removal of the PersistentVolumeClaim object is postponed until the snapshot is readyToUse or aborted.
### Delete
Deletion removes both the `VolumeSnapshotContent` object from the Kubernetes API, as well as the associated storage asset in the external infrastructure.
## Volume Snapshot Contents
Each VolumeSnapshotContent contains a spec, which is the specification of the volume snapshot.
```yaml
apiVersion: snapshot.storage.k8s.io/v1alpha1
kind: VolumeSnapshotContent
metadata:
name: new-snapshot-content-test
spec:
snapshotClassName: csi-hostpath-snapclass
source:
name: pvc-test
kind: PersistentVolumeClaim
volumeSnapshotSource:
csiVolumeSnapshotSource:
creationTime: 1535478900692119403
driver: csi-hostpath
restoreSize: 10Gi
snapshotHandle: 7bdd0de3-aaeb-11e8-9aae-0242ac110002
```
### Class
A VolumeSnapshotContent can have a class, which is specified by setting the
`snapshotClassName` attribute to the name of a
[VolumeSnapshotClass](/docs/concepts/storage/volume-snapshot-classes/).
A VolumeSnapshotContent of a particular class can only be bound to VolumeSnapshots requesting
that class. A VolumeSnapshotContent with no `snapshotClassName` has no class and can only be bound
to VolumeSnapshots that request no particular class.
Deletion is triggered by deleting the `VolumeSnapshot` object, and the `DeletionPolicy` will be followed. If the `DeletionPolicy` is `Delete`, then the underlying storage snapshot will be deleted along with the `VolumeSnapshotContent` object. If the `DeletionPolicy` is `Retain`, then both the underlying snapshot and `VolumeSnapshotContent` remain.
## VolumeSnapshots
Each VolumeSnapshot contains a spec and a status, which is the specification and status of the volume snapshot.
Each VolumeSnapshot contains a spec and a status.
```yaml
apiVersion: snapshot.storage.k8s.io/v1alpha1
apiVersion: snapshot.storage.k8s.io/v1beta1
kind: VolumeSnapshot
metadata:
name: new-snapshot-test
spec:
snapshotClassName: csi-hostpath-snapclass
volumeSnapshotClassName: csi-hostpath-snapclass
source:
name: pvc-test
kind: PersistentVolumeClaim
persistentVolumeClaimName: pvc-test
```
### Class
`persistentVolumeClaimName` is the name of the PersistentVolumeClaim data source for the snapshot. This field is required for dynamically provisioning a snapshot.
A volume snapshot can request a particular class by specifying the name of a
[VolumeSnapshotClass](/docs/concepts/storage/volume-snapshot-classes/)
using the attribute `snapshotClassName`.
Only VolumeSnapshotContents of the requested class, ones with the same `snapshotClassName`
as the VolumeSnapshot, can be bound to the VolumeSnapshot.
using the attribute `volumeSnapshotClassName`. If nothing is set, then the default class is used if available.
For pre-provisioned snapshots, you need to specify a `volumeSnapshotContentName` as the source for the snapshot as shown in the following example. The `volumeSnapshotContentName` source field is required for pre-provisioned snapshots.
```
apiVersion: snapshot.storage.k8s.io/v1beta1
kind: VolumeSnapshot
metadata:
name: test-snapshot
spec:
source:
volumeSnapshotContentName: test-content
```
## Volume Snapshot Contents
Each VolumeSnapshotContent contains a spec and status. In dynamic provisioning, the snapshot common controller creates `VolumeSnapshotContent` objects. Here is an example:
```yaml
apiVersion: snapshot.storage.k8s.io/v1beta1
kind: VolumeSnapshotContent
metadata:
name: snapcontent-72d9a349-aacd-42d2-a240-d775650d2455
spec:
deletionPolicy: Delete
driver: hostpath.csi.k8s.io
source:
volumeHandle: ee0cfb94-f8d4-11e9-b2d8-0242ac110002
volumeSnapshotClassName: csi-hostpath-snapclass
volumeSnapshotRef:
name: new-snapshot-test
namespace: default
uid: 72d9a349-aacd-42d2-a240-d775650d2455
```
`volumeHandle` is the unique identifier of the volume created on the storage backend and returned by the CSI driver during the volume creation. This field is required for dynamically provisioning a snapshot. It specifies the volume source of the snapshot.
For pre-provisioned snapshots, you (as cluster administrator) are responsible for creating the `VolumeSnapshotContent` object as follows.
```yaml
apiVersion: snapshot.storage.k8s.io/v1beta1
kind: VolumeSnapshotContent
metadata:
name: new-snapshot-content-test
spec:
deletionPolicy: Delete
driver: hostpath.csi.k8s.io
source:
snapshotHandle: 7bdd0de3-aaeb-11e8-9aae-0242ac110002
volumeSnapshotRef:
name: new-snapshot-test
namespace: default
```
`snapshotHandle` is the unique identifier of the volume snapshot created on the storage backend. This field is required for the pre-provisioned snapshots. It specifies the CSI snapshot id on the storage system that this `VolumeSnapshotContent` represents.
## Provisioning Volumes from Snapshots