---
title: 配置 Pod 的服务质量
content_type: task
weight: 60
---

<!--
title: Configure Quality of Service for Pods
content_type: task
weight: 60
-->

<!-- overview -->

<!--
This page shows how to configure Pods so that they will be assigned particular
{{< glossary_tooltip text="Quality of Service (QoS) classes" term_id="qos-class" >}}.
Kubernetes uses QoS classes to make decisions about evicting Pods when Node resources are exceeded.
-->
本页介绍怎样配置 Pod 以让其归属于特定的
{{< glossary_tooltip text="服务质量类（Quality of Service class，QoS class）" term_id="qos-class" >}}.
Kubernetes 在 Node 资源不足时使用 QoS 类来就驱逐 Pod 作出决定。

<!--
When Kubernetes creates a Pod it assigns one of these QoS classes to the Pod:

* [Guaranteed](/docs/concepts/workloads/pods/pod-qos/#guaranteed)
* [Burstable](/docs/concepts/workloads/pods/pod-qos/#burstable)
* [BestEffort](/docs/concepts/workloads/pods/pod-qos/#besteffort)
-->
Kubernetes 创建 Pod 时，会将如下 QoS 类之一设置到 Pod 上：

* [Guaranteed](/zh-cn/docs/concepts/workloads/pods/pod-qos/#guaranteed)
* [Burstable](/zh-cn/docs/concepts/workloads/pods/pod-qos/#burstable)
* [BestEffort](/zh-cn/docs/concepts/workloads/pods/pod-qos/#besteffort)

{{< note >}}
<!--
Kubernetes assigns the QoS class when the Pod is created, and it remains unchanged
for the lifetime of the Pod. If you attempt to
[resize the Pod's resources](/docs/tasks/configure-pod-container/resize-container-resources/)
to values that would result in a different QoS class, control plane rejects your request with an error message.
-->
Kubernetes 在创建 Pod 时会分配 QoS 类，并且这一 QoS 类在
Pod 的整个生命周期内保持不变。
如果你尝试将 [Pod 资源调整](/zh-cn/docs/tasks/configure-pod-container/resize-container-resources/)为会导致不同
QoS 类的值，控制平面将拒绝你的请求并返回错误消息。
{{< /note >}}

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

{{< include "task-tutorial-prereqs.md" >}}

<!--
You also need to be able to create and delete namespaces.
-->
你还需要能够创建和删除名字空间。

<!-- steps -->

<!--
## Create a namespace

Create a namespace so that the resources you create in this exercise are
isolated from the rest of your cluster.
-->
## 创建名字空间  {#create-a-namespace}

创建一个名字空间，以便将本练习所创建的资源与集群的其余资源相隔离。

```shell
kubectl create namespace qos-example
```

<!--
## Create a Pod that gets assigned a QoS class of Guaranteed

For a Pod to be given a QoS class of `Guaranteed`:

* Every Container in the Pod must have a memory limit and a memory request.
* For every Container in the Pod, the memory limit must equal the memory request.
* Every Container in the Pod must have a CPU limit and a CPU request.
* For every Container in the Pod, the CPU limit must equal the CPU request.

-->
## 创建一个 QoS 类为 Guaranteed 的 Pod  {#create-a-pod-that-gets-assigned-a-qos-class-of-guaranteed}

对于 QoS 类为 `Guaranteed` 的 Pod：

* Pod 中的每个容器都必须指定内存限制和内存请求。
* 对于 Pod 中的每个容器，内存限制必须等于内存请求。
* Pod 中的每个容器都必须指定 CPU 限制和 CPU 请求。
* 对于 Pod 中的每个容器，CPU 限制必须等于 CPU 请求。

<!--
These restrictions apply to init containers and app containers equally.
[Ephemeral containers](/docs/concepts/workloads/pods/ephemeral-containers/)
cannot define resources so these restrictions do not apply.

Here is a manifest for a Pod that has one Container. The Container has a memory limit and a
memory request, both equal to 200 MiB. The Container has a CPU limit and a CPU request, both equal to 700 milliCPU:
-->

这些限制同样适用于初始化容器和应用程序容器。
[临时容器（Ephemeral Container）](/zh-cn/docs/concepts/workloads/pods/ephemeral-containers/)
无法定义资源，因此不受这些约束限制。

下面是包含一个 Container 的 Pod 清单。该 Container 设置了内存请求和内存限制，值都是 200 MiB。
该 Container 设置了 CPU 请求和 CPU 限制，值都是 700 milliCPU：

{{% code_sample file="pods/qos/qos-pod.yaml" %}}

<!--
Create the Pod:
-->
创建 Pod：

```shell
kubectl apply -f https://k8s.io/examples/pods/qos/qos-pod.yaml --namespace=qos-example
```

<!--
View detailed information about the Pod:
-->
查看 Pod 详情：

```shell
kubectl get pod qos-demo --namespace=qos-example --output=yaml
```

<!--
The output shows that Kubernetes gave the Pod a QoS class of `Guaranteed`. The output also
verifies that the Pod Container has a memory request that matches its memory limit, and it has
a CPU request that matches its CPU limit.
-->
结果表明 Kubernetes 为 Pod 配置的 QoS 类为 `Guaranteed`。
结果也确认了 Pod 容器设置了与内存限制匹配的内存请求，设置了与 CPU 限制匹配的 CPU 请求。

```yaml
spec:
  containers:
    ...
    resources:
      limits:
        cpu: 700m
        memory: 200Mi
      requests:
        cpu: 700m
        memory: 200Mi
    ...
status:
  qosClass: Guaranteed
```

{{< note >}}
<!--
If a Container specifies its own memory limit, but does not specify a memory request, Kubernetes
automatically assigns a memory request that matches the limit. Similarly, if a Container specifies its own
CPU limit, but does not specify a CPU request, Kubernetes automatically assigns a CPU request that matches
the limit.
-->
如果某 Container 指定了自己的内存限制，但没有指定内存请求，Kubernetes
会自动为它指定与内存限制相等的内存请求。同样，如果容器指定了自己的 CPU 限制，
但没有指定 CPU 请求，Kubernetes 会自动为它指定与 CPU 限制相等的 CPU 请求。
{{< /note >}}

<!--
#### Clean up {#clean-up-guaranteed}
-->
#### 清理 {#clean-up-guaranteed}

<!--
Delete your Pod:
-->
删除 Pod：

```shell
kubectl delete pod qos-demo --namespace=qos-example
```

<!--
## Create a Pod that gets assigned a QoS class of Burstable

A Pod is given a QoS class of `Burstable` if:

* The Pod does not meet the criteria for QoS class `Guaranteed`.
* At least one Container in the Pod has a memory or CPU request or limit.

Here is a manifest for a Pod that has one Container. The Container has a memory limit of 200 MiB
and a memory request of 100 MiB.
-->
## 创建一个 QoS 类为 Burstable 的 Pod  {#create-a-pod-that-gets-assigned-a-qos-class-of-burstable}

如果满足下面条件，Kubernetes 将会指定 Pod 的 QoS 类为 `Burstable`：

* Pod 不符合 `Guaranteed` QoS 类的标准。
* Pod 中至少一个 Container 具有内存或 CPU 的请求或限制。

下面是包含一个 Container 的 Pod 清单。该 Container 设置的内存限制为 200 MiB，
内存请求为 100 MiB。

{{% code_sample file="pods/qos/qos-pod-2.yaml" %}}

<!--
Create the Pod:
-->
创建 Pod：

```shell
kubectl apply -f https://k8s.io/examples/pods/qos/qos-pod-2.yaml --namespace=qos-example
```

<!--
View detailed information about the Pod:
-->
查看 Pod 详情：

```shell
kubectl get pod qos-demo-2 --namespace=qos-example --output=yaml
```

<!--
The output shows that Kubernetes gave the Pod a QoS class of `Burstable`:
-->
结果表明 Kubernetes 为 Pod 配置的 QoS 类为 `Burstable`：

```yaml
spec:
  containers:
  - image: nginx
    imagePullPolicy: Always
    name: qos-demo-2-ctr
    resources:
      limits:
        memory: 200Mi
      requests:
        memory: 100Mi
  ...
status:
  qosClass: Burstable
```

<!--
#### Clean up {#clean-up-burstable}
-->
#### 清理  {#clean-up-burstable}

<!--
Delete your Pod:
-->
删除 Pod：

```shell
kubectl delete pod qos-demo-2 --namespace=qos-example
```

<!--
## Create a Pod that gets assigned a QoS class of BestEffort

For a Pod to be given a QoS class of `BestEffort`, the Containers in the Pod must not
have any memory or CPU limits or requests.

Here is a manifest for a Pod that has one Container. The Container has no memory or CPU
limits or requests:
-->
## 创建一个 QoS 类为 BestEffort 的 Pod  {#create-a-pod-that-gets-assigned-a-qos-class-of-besteffort}

对于 QoS 类为 `BestEffort` 的 Pod，Pod 中的 Container 必须没有设置内存和 CPU 限制或请求。

下面是包含一个 Container 的 Pod 清单。该 Container 没有设置内存和 CPU 限制或请求。

{{% code_sample file="pods/qos/qos-pod-3.yaml" %}}

<!--
Create the Pod:
-->
创建 Pod：

```shell
kubectl apply -f https://k8s.io/examples/pods/qos/qos-pod-3.yaml --namespace=qos-example
```

<!--
View detailed information about the Pod:
-->
查看 Pod 详情：

```shell
kubectl get pod qos-demo-3 --namespace=qos-example --output=yaml
```

<!--
The output shows that Kubernetes gave the Pod a QoS class of `BestEffort`:
-->
结果表明 Kubernetes 为 Pod 配置的 QoS 类为 `BestEffort`。

```yaml
spec:
  containers:
    ...
    resources: {}
  ...
status:
  qosClass: BestEffort
```

<!--
#### Clean up {#clean-up-besteffort}
-->
#### 清理   {#clean-up-besteffort}

<!--
Delete your Pod:
-->
删除 Pod：

```shell
kubectl delete pod qos-demo-3 --namespace=qos-example
```

<!--
## Create a Pod that has two Containers

Here is a manifest for a Pod that has two Containers. One container specifies a memory
request of 200 MiB. The other Container does not specify any requests or limits.
-->
## 创建包含两个容器的 Pod  {#create-a-pod-that-has-two-containers}

下面是包含两个 Container 的 Pod 清单。一个 Container 指定内存请求为 200 MiB。
另外一个 Container 没有指定任何请求或限制。

{{% code_sample file="pods/qos/qos-pod-4.yaml" %}}

<!--
Notice that this Pod meets the criteria for QoS class `Burstable`. That is, it does not meet the
criteria for QoS class `Guaranteed`, and one of its Containers has a memory request.

Create the Pod:
-->
注意此 Pod 满足 `Burstable` QoS 类的标准。也就是说它不满足 `Guaranteed` QoS 类标准，
因为它的 Container 之一设有内存请求。

创建 Pod：

```shell
kubectl apply -f https://k8s.io/examples/pods/qos/qos-pod-4.yaml --namespace=qos-example
```

<!--
View detailed information about the Pod:
-->
查看 Pod 详情：

```shell
kubectl get pod qos-demo-4 --namespace=qos-example --output=yaml
```

<!--
The output shows that Kubernetes gave the Pod a QoS class of `Burstable`:
-->
结果表明 Kubernetes 为 Pod 配置的 QoS 类为 `Burstable`：

```yaml
spec:
  containers:
    ...
    name: qos-demo-4-ctr-1
    resources:
      requests:
        memory: 200Mi
    ...
    name: qos-demo-4-ctr-2
    resources: {}
    ...
status:
  qosClass: Burstable
```

<!--
## Retrieve the QoS class for a Pod

Rather than see all the fields, you can view just the field you need:
-->
## 检视 Pod 的 QoS 类  {#retrieve-the-qos-class-for-a-pod}

<!--
Rather than see all the fields, you can view just the field you need:
-->
你也可以只查看你所需要的字段，而不是查看所有字段：

```bash
kubectl --namespace=qos-example get pod qos-demo-4 -o jsonpath='{ .status.qosClass}{"\n"}'
```

```none
Burstable
```

<!--
## Clean up

Delete your namespace:
-->
## 环境清理  {#clean-up}

删除名字空间：

```shell
kubectl delete namespace qos-example
```

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

<!--
### For app developers

* [Assign Memory Resources to Containers and Pods](/docs/tasks/configure-pod-container/assign-memory-resource/)

* [Assign CPU Resources to Containers and Pods](/docs/tasks/configure-pod-container/assign-cpu-resource/)
-->
### 应用开发者参考

* [为 Pod 和容器分配内存资源](/zh-cn/docs/tasks/configure-pod-container/assign-memory-resource/)
* [为 Pod 和容器分配 CPU 资源](/zh-cn/docs/tasks/configure-pod-container/assign-cpu-resource/)

<!--
### For cluster administrators

* [Configure Default Memory Requests and Limits for a Namespace](/docs/tasks/administer-cluster/manage-resources/memory-default-namespace/)

* [Configure Default CPU Requests and Limits for a Namespace](/docs/tasks/administer-cluster/manage-resources/cpu-default-namespace/)

* [Configure Minimum and Maximum Memory Constraints for a Namespace](/docs/tasks/administer-cluster/manage-resources/memory-constraint-namespace/)

* [Configure Minimum and Maximum CPU Constraints for a Namespace](/docs/tasks/administer-cluster/manage-resources/cpu-constraint-namespace/)

* [Configure Memory and CPU Quotas for a Namespace](/docs/tasks/administer-cluster/manage-resources/quota-memory-cpu-namespace/)

* [Configure a Pod Quota for a Namespace](/docs/tasks/administer-cluster/manage-resources/quota-pod-namespace/)

* [Configure Quotas for API Objects](/docs/tasks/administer-cluster/quota-api-object/)

* [Control Topology Management policies on a node](/docs/tasks/administer-cluster/topology-manager/)
-->
### 集群管理员参考

* [为名字空间配置默认的内存请求和限制](/zh-cn/docs/tasks/administer-cluster/manage-resources/memory-default-namespace/)
* [为名字空间配置默认的 CPU 请求和限制](/zh-cn/docs/tasks/administer-cluster/manage-resources/cpu-default-namespace/)
* [为名字空间配置最小和最大内存限制](/zh-cn/docs/tasks/administer-cluster/manage-resources/memory-constraint-namespace/)
* [为名字空间配置最小和最大 CPU 限制](/zh-cn/docs/tasks/administer-cluster/manage-resources/cpu-constraint-namespace/)
* [为名字空间配置内存和 CPU 配额](/zh-cn/docs/tasks/administer-cluster/manage-resources/quota-memory-cpu-namespace/)
* [为名字空间配置 Pod 配额](/zh-cn/docs/tasks/administer-cluster/manage-resources/quota-pod-namespace/)
* [为 API 对象配置配额](/zh-cn/docs/tasks/administer-cluster/quota-api-object/)
* [控制节点上的拓扑管理策略](/zh-cn/docs/tasks/administer-cluster/topology-manager/)