170 lines
6.5 KiB
Markdown
170 lines
6.5 KiB
Markdown
---
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title: 卷快照类
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content_type: concept
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weight: 61 # 置于卷快照章节后
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---
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<!-- overview -->
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<!--
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This document describes the concept of VolumeSnapshotClass in Kubernetes. Familiarity
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with [volume snapshots](/docs/concepts/storage/volume-snapshots/) and
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[storage classes](/docs/concepts/storage/storage-classes) is suggested.
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-->
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本文档描述了 Kubernetes 中 VolumeSnapshotClass 的概念。建议熟悉
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[卷快照（Volume Snapshots）](/zh-cn/docs/concepts/storage/volume-snapshots/)和
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[存储类（Storage Class）](/zh-cn/docs/concepts/storage/storage-classes)。
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<!-- body -->
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<!--
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## Introduction
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Just like StorageClass provides a way for administrators to describe the "classes"
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of storage they offer when provisioning a volume, VolumeSnapshotClass provides a
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way to describe the "classes" of storage when provisioning a volume snapshot.
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-->
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## 介绍 {#introduction}
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就像 StorageClass 为管理员提供了一种在配置卷时描述存储“类”的方法，
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VolumeSnapshotClass 提供了一种在配置卷快照时描述存储“类”的方法。
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<!--
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## The VolumeSnapshotClass Resource
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Each VolumeSnapshotClass contains the fields `driver`, `deletionPolicy`, and `parameters`,
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which are used when a VolumeSnapshot belonging to the class needs to be
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dynamically provisioned.
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The name of a VolumeSnapshotClass object is significant, and is how users can
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request a particular class. Administrators set the name and other parameters
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of a class when first creating VolumeSnapshotClass objects, and the objects cannot
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be updated once they are created.
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{{< note >}}
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Installation of the CRDs is the responsibility of the Kubernetes distribution.
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Without the required CRDs present, the creation of a VolumeSnapshotClass fails.
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{{< /note >}}
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-->
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## VolumeSnapshotClass 资源 {#the-volumesnapshortclass-resource}
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每个 VolumeSnapshotClass 都包含 `driver`、`deletionPolicy` 和 `parameters` 字段，
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在需要动态配置属于该类的 VolumeSnapshot 时使用。
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VolumeSnapshotClass 对象的名称很重要，是用户可以请求特定类的方式。
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管理员在首次创建 VolumeSnapshotClass 对象时设置类的名称和其他参数，
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对象一旦创建就无法更新。
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{{< note >}}
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CRD 的安装是 Kubernetes 发行版的责任。 如果不存在所需的 CRD，则 VolumeSnapshotClass 的创建将失败。
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{{< /note >}}
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```yaml
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apiVersion: snapshot.storage.k8s.io/v1
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kind: VolumeSnapshotClass
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metadata:
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name: csi-hostpath-snapclass
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driver: hostpath.csi.k8s.io
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deletionPolicy: Delete
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parameters:
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```
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<!--
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Administrators can specify a default VolumeSnapshotClass for VolumeSnapshots
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that don't request any particular class to bind to by adding the
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`snapshot.storage.kubernetes.io/is-default-class: "true"` annotation:
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-->
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管理员可以为未请求任何特定类绑定的 VolumeSnapshots 指定默认的 VolumeSnapshotClass，
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方法是设置注解 `snapshot.storage.kubernetes.io/is-default-class: "true"`：
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```yaml
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apiVersion: snapshot.storage.k8s.io/v1
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kind: VolumeSnapshotClass
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metadata:
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name: csi-hostpath-snapclass
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annotations:
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snapshot.storage.kubernetes.io/is-default-class: "true"
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driver: hostpath.csi.k8s.io
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deletionPolicy: Delete
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parameters:
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```
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<!--
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If multiple CSI drivers exist, a default VolumeSnapshotClass can be specified
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for each of them.
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-->
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如果存在多个 CSI 驱动程序，可以为每个驱动程序指定一个默认的 VolumeSnapshotClass。
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<!--
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### VolumeSnapshotClass dependencies
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When you create a VolumeSnapshot without specifying a VolumeSnapshotClass, Kubernetes
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automatically selects a default VolumeSnapshotClass that has a CSI driver matching
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the CSI driver of the PVC’s StorageClass.
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This behavior allows multiple default VolumeSnapshotClass objects to coexist in a cluster, as long as
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each one is associated with a unique CSI driver.
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Always ensure that there is only one default VolumeSnapshotClass for each CSI driver. If
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multiple default VolumeSnapshotClass objects are created using the same CSI driver,
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a VolumeSnapshot creation will fail because Kubernetes cannot determine which one to use.
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-->
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### VolumeSnapshotClass 依赖关系 {#volumesnapshotclass-dependencies}
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当你创建一个 VolumeSnapshot 且未指定 VolumeSnapshotClass 时，
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Kubernetes 会自动选择一个默认的 VolumeSnapshotClass，
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该类与 PVC 的 StorageClass 所使用的 CSI 驱动程序匹配。
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这种行为允许多个默认的 VolumeSnapshotClass 对象在集群中共存，
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只要每个默认类都与唯一的 CSI 驱动程序进行关联。
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请始终确保每个 CSI 驱动程序只有一个默认的 VolumeSnapshotClass。
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如果使用相同的 CSI 驱动程序创建了多个默认的 VolumeSnapshotClass 对象，
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则创建 VolumeSnapshot 时会失败，因为 Kubernetes 无法确定使用哪个类。
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<!--
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### Driver
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Volume snapshot classes have a driver that determines what CSI volume plugin is
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used for provisioning VolumeSnapshots. This field must be specified.
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-->
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### 驱动程序 {#driver}
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卷快照类有一个驱动程序，用于确定配置 VolumeSnapshot 的 CSI 卷插件。
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此字段必须指定。
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<!--
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### DeletionPolicy
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Volume snapshot classes have a [deletionPolicy](/docs/concepts/storage/volume-snapshots/#delete).
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It enables you to configure what happens to a VolumeSnapshotContent when the VolumeSnapshot
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object it is bound to is to be deleted. The deletionPolicy of a volume snapshot class can
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either be `Retain` or `Delete`. This field must be specified.
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If the deletionPolicy is `Delete`, then the underlying storage snapshot will be
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deleted along with the VolumeSnapshotContent object. If the deletionPolicy is `Retain`,
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then both the underlying snapshot and VolumeSnapshotContent remain.
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-->
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### 删除策略 {#deletion-policy}
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卷快照类具有 [deletionPolicy](/zh-cn/docs/concepts/storage/volume-snapshots/#delete) 属性。
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用户可以配置当所绑定的 VolumeSnapshot 对象将被删除时，如何处理 VolumeSnapshotContent 对象。
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卷快照类的这个策略可以是 `Retain` 或者 `Delete`。这个策略字段必须指定。
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如果删除策略是 `Delete`，那么底层的存储快照会和 VolumeSnapshotContent 对象
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一起删除。如果删除策略是 `Retain`，那么底层快照和 VolumeSnapshotContent
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对象都会被保留。
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<!--
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## Parameters
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Volume snapshot classes have parameters that describe volume snapshots belonging to
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the volume snapshot class. Different parameters may be accepted depending on the
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`driver`.
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-->
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## 参数 {#parameters}
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卷快照类具有描述属于该卷快照类的卷快照的参数，可根据 `driver` 接受不同的参数。
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