---
title: 扩缩 StatefulSet
content_type: task
weight: 50
---
<!--
reviewers:
- bprashanth
- enisoc
- erictune
- foxish
- janetkuo
- kow3ns
- smarterclayton
title: Scale a StatefulSet
content_type: task
weight: 50
-->

<!-- overview -->
<!--
This task shows how to scale a StatefulSet. Scaling a StatefulSet refers to
increasing or decreasing the number of replicas.
-->
本文介绍如何扩缩 StatefulSet。StatefulSet 的扩缩指的是增加或者减少副本个数。

## {{% heading "prerequisites" %}}

<!--
- StatefulSets are only available in Kubernetes version 1.5 or later.
  To check your version of Kubernetes, run `kubectl version`.

- Not all stateful applications scale nicely. If you are unsure about whether
  to scale your StatefulSets, see [StatefulSet concepts](/docs/concepts/workloads/controllers/statefulset/)
  or [StatefulSet tutorial](/docs/tutorials/stateful-application/basic-stateful-set/) for further information.

- You should perform scaling only when you are confident that your stateful application
  cluster is completely healthy.
-->
- StatefulSets 仅适用于 Kubernetes 1.5 及以上版本。
  要查看你的 Kubernetes 版本，运行 `kubectl version`。
- 不是所有 Stateful 应用都能很好地执行扩缩操作。
  如果你不是很确定是否要扩缩你的 StatefulSet，可先参阅
  [StatefulSet 概念](/zh-cn/docs/concepts/workloads/controllers/statefulset/)
  或者 [StatefulSet 教程](/zh-cn/docs/tutorials/stateful-application/basic-stateful-set/)。

- 仅当你确定你的有状态应用的集群是完全健康的，才可执行扩缩操作.

<!-- steps -->

<!--
## Scaling StatefulSets

### Use kubectl to scale StatefulSets

First, find the StatefulSet you want to scale.

```shell
kubectl get statefulsets <stateful-set-name>
```
-->
## 扩缩 StatefulSet   {#scaling-statefulset}

### 使用 `kubectl` 扩缩 StatefulSet    {#use-kubectl-to-scale-statefulsets}

首先，找到你要扩缩的 StatefulSet。

```shell
kubectl get statefulsets <statefulset 名称>
```

<!--
Change the number of replicas of your StatefulSet:

```shell
kubectl scale statefulsets <stateful-set-name> --replicas=<new-replicas>
```
-->
更改 StatefulSet 中副本个数：

```shell
kubectl scale statefulsets <statefulset 名称> --replicas=<新的副本数>
```

<!--
### Make in-place updates on your StatefulSets

Alternatively, you can do
[in-place updates](/docs/concepts/cluster-administration/manage-deployment/#in-place-updates-of-resources)
on your StatefulSets.

If your StatefulSet was initially created with `kubectl apply`,
update `.spec.replicas` of the StatefulSet manifests, and then do a `kubectl apply`:
-->
### 对 StatefulSet 执行就地更新    {#make-in-place-updates-on-statefulset}

另外, 你可以[就地更新](/zh-cn/docs/concepts/cluster-administration/manage-deployment/#in-place-updates-of-resources) StatefulSet。

如果你的 StatefulSet 最初通过 `kubectl apply` 或 `kubectl create --save-config` 创建，
你可以更新 StatefulSet 清单中的 `.spec.replicas`，然后执行命令 `kubectl apply`：

<!--
```shell
kubectl apply -f <stateful-set-file-updated>
```

Otherwise, edit that field with `kubectl edit`:

```shell
kubectl edit statefulsets <stateful-set-name>
```

Or use `kubectl patch`:

```shell
kubectl patch statefulsets <stateful-set-name> -p '{"spec":{"replicas":<new-replicas>}}'
```
-->
```shell
kubectl apply -f <更新后的 statefulset 文件>
```

否则，可以使用 `kubectl edit` 编辑副本字段：

```shell
kubectl edit statefulsets <statefulset 名称>
```

或者使用 `kubectl patch`：

```shell
kubectl patch statefulsets <statefulset 名称> -p '{"spec":{"replicas":<new-replicas>}}'
```

<!--
## Troubleshooting

### Scaling down does not work right
-->
## 故障排查  {#troubleshooting}

### 缩容操作无法正常工作   {#scaling-down-does-not-work}

<!--
You cannot scale down a StatefulSet when any of the stateful Pods it manages is
unhealthy. Scaling down only takes place after those stateful Pods become running and ready.

If spec.replicas > 1, Kubernetes cannot determine the reason for an unhealthy Pod.
It might be the result of a permanent fault or of a transient fault. A transient
fault can be caused by a restart required by upgrading or maintenance.
-->
当 Stateful 所管理的任何 Pod 不健康时，你不能对该 StatefulSet 执行缩容操作。
仅当 StatefulSet 的所有 Pod 都处于运行状态和 Ready 状况后才可缩容。

如果 `spec.replicas` 大于 1，Kubernetes 无法判定 Pod 不健康的原因。
Pod 不健康可能是由于永久性故障造成也可能是瞬态故障。
瞬态故障可能是节点升级或维护而引起的节点重启造成的。

<!--
If the Pod is unhealthy due to a permanent fault, scaling
without correcting the fault may lead to a state where the StatefulSet membership
drops below a certain minimum number of replicas that are needed to function
correctly. This may cause your StatefulSet to become unavailable.
-->
如果该 Pod 不健康是由于永久性故障导致，则在不纠正该故障的情况下进行缩容可能会导致
StatefulSet 进入一种状态，其成员 Pod 数量低于应正常运行的副本数。
这种状态也许会导致 StatefulSet 不可用。

<!--
If the Pod is unhealthy due to a transient fault and the Pod might become available again,
the transient error may interfere with your scale-up or scale-down operation. Some distributed
databases have issues when nodes join and leave at the same time. It is better
to reason about scaling operations at the application level in these cases, and
perform scaling only when you are sure that your stateful application cluster is
completely healthy.
-->
如果由于瞬态故障而导致 Pod 不健康并且 Pod 可能再次变为可用，那么瞬态错误可能会干扰你对
StatefulSet 的扩容/缩容操作。一些分布式数据库在同时有节点加入和离开时会遇到问题。
在这些情况下，最好是在应用级别进行分析扩缩操作的状态，并且只有在确保
Stateful 应用的集群是完全健康时才执行扩缩操作。

## {{% heading "whatsnext" %}}

<!--
- Learn more about [deleting a StatefulSet](/docs/tasks/run-application/delete-stateful-set/).
-->
- 进一步了解[删除 StatefulSet](/zh-cn/docs/tasks/run-application/delete-stateful-set/)。