558 lines
18 KiB
Markdown
558 lines
18 KiB
Markdown
---
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title: 为容器和 Pod 分配内存资源
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content_type: task
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weight: 10
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---
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<!--
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title: Assign Memory Resources to Containers and Pods
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content_type: task
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weight: 10
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-->
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<!-- overview -->
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<!--
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This page shows how to assign a memory *request* and a memory *limit* to a
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Container. A Container is guaranteed to have as much memory as it requests,
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but is not allowed to use more memory than its limit.
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-->
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此页面展示如何将内存 *请求* （request）和内存 *限制* （limit）分配给一个容器。
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我们保障容器拥有它请求数量的内存，但不允许使用超过限制数量的内存。
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## {{% heading "prerequisites" %}}
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{{< include "task-tutorial-prereqs.md" >}} {{< version-check >}}
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<!--
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Each node in your cluster must have at least 300 MiB of memory.
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-->
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你集群中的每个节点必须拥有至少 300 MiB 的内存。
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<!--
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A few of the steps on this page require you to run the
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[metrics-server](https://github.com/kubernetes-sigs/metrics-server)
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service in your cluster. If you have the metrics-server
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running, you can skip those steps.
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-->
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该页面上的一些步骤要求你在集群中运行
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[metrics-server](https://github.com/kubernetes-sigs/metrics-server) 服务。
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如果你已经有在运行中的 metrics-server，则可以跳过这些步骤。
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<!--
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If you are running Minikube, run the following command to enable the
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metrics-server:
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-->
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如果你运行的是 Minikube，可以运行下面的命令启用 metrics-server：
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```shell
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minikube addons enable metrics-server
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```
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<!--
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To see whether the metrics-server is running, or another provider of the resource metrics
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API (`metrics.k8s.io`), run the following command:
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-->
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要查看 metrics-server 或资源指标 API (`metrics.k8s.io`) 是否已经运行，请运行以下命令：
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```shell
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kubectl get apiservices
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```
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<!--
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If the resource metrics API is available, the output includes a
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reference to `metrics.k8s.io`.
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-->
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如果资源指标 API 可用，则输出结果将包含对 `metrics.k8s.io` 的引用信息。
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```
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NAME
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v1beta1.metrics.k8s.io
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```
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<!-- steps -->
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<!--
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## Create a namespace
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Create a namespace so that the resources you create in this exercise are
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isolated from the rest of your cluster.
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-->
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## 创建命名空间
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创建一个命名空间，以便将本练习中创建的资源与集群的其余部分隔离。
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```shell
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kubectl create namespace mem-example
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```
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<!--
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## Specify a memory request and a memory limit
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To specify a memory request for a Container, include the `resources:requests` field
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in the Container's resource manifest. To specify a memory limit, include `resources:limits`.
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In this exercise, you create a Pod that has one Container. The Container has a memory
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request of 100 MiB and a memory limit of 200 MiB. Here's the configuration file
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for the Pod:
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-->
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## 指定内存请求和限制
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要为容器指定内存请求，请在容器资源清单中包含 `resources：requests` 字段。
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同理，要指定内存限制，请包含 `resources：limits`。
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在本练习中，你将创建一个拥有一个容器的 Pod。
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容器将会请求 100 MiB 内存，并且内存会被限制在 200 MiB 以内。
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这是 Pod 的配置文件：
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{{< codenew file="pods/resource/memory-request-limit.yaml" >}}
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<!--
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The `args` section in the configuration file provides arguments for the Container when it starts.
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The `"--vm-bytes", "150M"` arguments tell the Container to attempt to allocate 150 MiB of memory.
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Create the Pod:
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-->
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配置文件的 `args` 部分提供了容器启动时的参数。
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`"--vm-bytes", "150M"` 参数告知容器尝试分配 150 MiB 内存。
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开始创建 Pod：
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```shell
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kubectl apply -f https://k8s.io/examples/pods/resource/memory-request-limit.yaml --namespace=mem-example
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```
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<!--
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Verify that the Pod Container is running:
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-->
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验证 Pod 中的容器是否已运行：
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```shell
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kubectl get pod memory-demo --namespace=mem-example
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```
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<!--
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View detailed information about the Pod:
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-->
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查看 Pod 相关的详细信息：
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```shell
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kubectl get pod memory-demo --output=yaml --namespace=mem-example
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```
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<!--
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The output shows that the one Container in the Pod has a memory request of 100 MiB
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and a memory limit of 200 MiB.
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-->
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输出结果显示：该 Pod 中容器的内存请求为 100 MiB，内存限制为 200 MiB。
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```yaml
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...
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resources:
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limits:
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memory: 200Mi
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requests:
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memory: 100Mi
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...
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```
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<!--
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Run `kubectl top` to fetch the metrics for the pod:
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-->
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运行 `kubectl top` 命令，获取该 Pod 的指标数据：
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```shell
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kubectl top pod memory-demo --namespace=mem-example
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```
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<!--
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The output shows that the Pod is using about 162,900,000 bytes of memory, which
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is about 150 MiB. This is greater than the Pod's 100 MiB request, but within the
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Pod's 200 MiB limit.
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-->
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输出结果显示：Pod 正在使用的内存大约为 162,900,000 字节，约为 150 MiB。
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这大于 Pod 请求的 100 MiB，但在 Pod 限制的 200 MiB之内。
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```
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NAME CPU(cores) MEMORY(bytes)
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memory-demo <something> 162856960
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```
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<!--
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Delete your Pod:
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-->
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删除 Pod：
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```shell
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kubectl delete pod memory-demo --namespace=mem-example
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```
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<!--
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## Exceed a Container's memory limit
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A Container can exceed its memory request if the Node has memory available. But a Container
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is not allowed to use more than its memory limit. If a Container allocates more memory than
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its limit, the Container becomes a candidate for termination. If the Container continues to
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consume memory beyond its limit, the Container is terminated. If a terminated Container can be
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restarted, the kubelet restarts it, as with any other type of runtime failure.
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-->
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## 超过容器限制的内存
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当节点拥有足够的可用内存时，容器可以使用其请求的内存。
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但是，容器不允许使用超过其限制的内存。
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如果容器分配的内存超过其限制，该容器会成为被终止的候选容器。
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如果容器继续消耗超出其限制的内存，则终止容器。
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如果终止的容器可以被重启，则 kubelet 会重新启动它，就像其他任何类型的运行时失败一样。
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<!--
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In this exercise, you create a Pod that attempts to allocate more memory than its limit.
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Here is the configuration file for a Pod that has one Container with a
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memory request of 50 MiB and a memory limit of 100 MiB:
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-->
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在本练习中，你将创建一个 Pod，尝试分配超出其限制的内存。
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这是一个 Pod 的配置文件，其拥有一个容器，该容器的内存请求为 50 MiB，内存限制为 100 MiB：
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{{< codenew file="pods/resource/memory-request-limit-2.yaml" >}}
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<!--
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In the `args` section of the configuration file, you can see that the Container
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will attempt to allocate 250 MiB of memory, which is well above the 100 MiB limit.
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Create the Pod:
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-->
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在配置文件的 `args` 部分中，你可以看到容器会尝试分配 250 MiB 内存，这远高于 100 MiB 的限制。
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创建 Pod：
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```shell
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kubectl apply -f https://k8s.io/examples/pods/resource/memory-request-limit-2.yaml --namespace=mem-example
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```
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<!--
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View detailed information about the Pod:
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-->
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查看 Pod 相关的详细信息：
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```shell
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kubectl get pod memory-demo-2 --namespace=mem-example
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```
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<!--
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At this point, the Container might be running or killed. Repeat the preceding command until the Container is killed:
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-->
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此时，容器可能正在运行或被杀死。重复前面的命令，直到容器被杀掉：
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```shell
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NAME READY STATUS RESTARTS AGE
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memory-demo-2 0/1 OOMKilled 1 24s
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```
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<!--
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Get a more detailed view of the Container status:
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-->
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获取容器更详细的状态信息：
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```shell
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kubectl get pod memory-demo-2 --output=yaml --namespace=mem-example
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```
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<!--
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The output shows that the Container was killed because it is out of memory (OOM):
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-->
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输出结果显示：由于内存溢出（OOM），容器已被杀掉：
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```shell
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lastState:
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terminated:
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containerID: docker://65183c1877aaec2e8427bc95609cc52677a454b56fcb24340dbd22917c23b10f
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exitCode: 137
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finishedAt: 2017-06-20T20:52:19Z
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reason: OOMKilled
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startedAt: null
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```
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<!--
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The Container in this exercise can be restarted, so the kubelet restarts it. Repeat
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this command several times to see that the Container is repeatedly killed and restarted:
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-->
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本练习中的容器可以被重启，所以 kubelet 会重启它。
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多次运行下面的命令，可以看到容器在反复的被杀死和重启：
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```shell
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kubectl get pod memory-demo-2 --namespace=mem-example
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```
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<!--
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The output shows that the Container is killed, restarted, killed again, restarted again, and so on:
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-->
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输出结果显示：容器被杀掉、重启、再杀掉、再重启……：
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```
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kubectl get pod memory-demo-2 --namespace=mem-example
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NAME READY STATUS RESTARTS AGE
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memory-demo-2 0/1 OOMKilled 1 37s
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```
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```
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kubectl get pod memory-demo-2 --namespace=mem-example
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NAME READY STATUS RESTARTS AGE
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memory-demo-2 1/1 Running 2 40s
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```
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<!--
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View detailed information about the Pod history:
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-->
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查看关于该 Pod 历史的详细信息：
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```
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kubectl describe pod memory-demo-2 --namespace=mem-example
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```
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<!--
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The output shows that the Container starts and fails repeatedly:
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-->
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输出结果显示：该容器反复的在启动和失败：
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```
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... Normal Created Created container with id 66a3a20aa7980e61be4922780bf9d24d1a1d8b7395c09861225b0eba1b1f8511
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... Warning BackOff Back-off restarting failed container
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```
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<!--
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View detailed information about your cluster's Nodes:
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-->
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查看关于集群节点的详细信息：
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```
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kubectl describe nodes
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```
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<!--
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The output includes a record of the Container being killed because of an out-of-memory condition:
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-->
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输出结果包含了一条练习中的容器由于内存溢出而被杀掉的记录：
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```
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Warning OOMKilling Memory cgroup out of memory: Kill process 4481 (stress) score 1994 or sacrifice child
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```
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<!--
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Delete your Pod:
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-->
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删除 Pod:
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```shell
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kubectl delete pod memory-demo-2 --namespace=mem-example
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```
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<!--
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## Specify a memory request that is too big for your Nodes
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Memory requests and limits are associated with Containers, but it is useful to think
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of a Pod as having a memory request and limit. The memory request for the Pod is the
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sum of the memory requests for all the Containers in the Pod. Likewise, the memory
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limit for the Pod is the sum of the limits of all the Containers in the Pod.
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-->
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## 超过整个节点容量的内存
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内存请求和限制是与容器关联的，但将 Pod 视为具有内存请求和限制，也是很有用的。
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Pod 的内存请求是 Pod 中所有容器的内存请求之和。
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同理，Pod 的内存限制是 Pod 中所有容器的内存限制之和。
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<!--
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Pod scheduling is based on requests. A Pod is scheduled to run on a Node only if the Node
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has enough available memory to satisfy the Pod's memory request.
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In this exercise, you create a Pod that has a memory request so big that it exceeds the
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capacity of any Node in your cluster. Here is the configuration file for a Pod that has one
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Container with a request for 1000 GiB of memory, which likely exceeds the capacity
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of any Node in your cluster.
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-->
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Pod 的调度基于请求。只有当节点拥有足够满足 Pod 内存请求的内存时，才会将 Pod 调度至节点上运行。
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在本练习中，你将创建一个 Pod，其内存请求超过了你集群中的任意一个节点所拥有的内存。
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这是该 Pod 的配置文件，其拥有一个请求 1000 GiB 内存的容器，这应该超过了你集群中任何节点的容量。
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{{< codenew file="pods/resource/memory-request-limit-3.yaml" >}}
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<!--
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Create the Pod:
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-->
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创建 Pod：
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```shell
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kubectl apply -f https://k8s.io/examples/pods/resource/memory-request-limit-3.yaml --namespace=mem-example
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```
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<!--
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View the Pod status:
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-->
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查看 Pod 状态：
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```shell
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kubectl get pod memory-demo-3 --namespace=mem-example
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```
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<!--
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The output shows that the Pod status is PENDING. That is, the Pod is not scheduled to run on any Node, and it will remain in the PENDING state indefinitely:
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-->
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输出结果显示：Pod 处于 PENDING 状态。
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这意味着，该 Pod 没有被调度至任何节点上运行，并且它会无限期的保持该状态：
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```
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kubectl get pod memory-demo-3 --namespace=mem-example
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NAME READY STATUS RESTARTS AGE
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memory-demo-3 0/1 Pending 0 25s
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```
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<!--
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View detailed information about the Pod, including events:
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-->
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查看关于 Pod 的详细信息，包括事件：
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```shell
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kubectl describe pod memory-demo-3 --namespace=mem-example
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```
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<!--
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The output shows that the Container cannot be scheduled because of insufficient memory on the Nodes:
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-->
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输出结果显示：由于节点内存不足，该容器无法被调度：
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```shell
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Events:
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... Reason Message
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------ -------
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... FailedScheduling No nodes are available that match all of the following predicates:: Insufficient memory (3).
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```
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<!--
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## Memory units
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The memory resource is measured in bytes. You can express memory as a plain integer or a
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fixed-point integer with one of these suffixes: E, P, T, G, M, K, Ei, Pi, Ti, Gi, Mi, Ki.
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For example, the following represent approximately the same value:
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-->
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## 内存单位
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内存资源的基本单位是字节（byte）。你可以使用这些后缀之一，将内存表示为
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纯整数或定点整数：E、P、T、G、M、K、Ei、Pi、Ti、Gi、Mi、Ki。
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例如，下面是一些近似相同的值：
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```shell
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128974848, 129e6, 129M , 123Mi
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```
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<!--
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Delete your Pod:
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-->
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删除 Pod：
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```shell
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kubectl delete pod memory-demo-3 --namespace=mem-example
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```
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<!--
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## If you do not specify a memory limit
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If you do not specify a memory limit for a Container, one of the following situations applies:
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-->
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## 如果你没有指定内存限制
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如果你没有为一个容器指定内存限制，则自动遵循以下情况之一：
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<!--
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* The Container has no upper bound on the amount of memory it uses. The Container
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could use all of the memory available on the Node where it is running which in turn could invoke the OOM Killer. Further, in case of an OOM Kill, a container with no resource limits will have a greater chance of being killed.
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* The Container is running in a namespace that has a default memory limit, and the
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Container is automatically assigned the default limit. Cluster administrators can use a
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[LimitRange](/docs/reference/generated/kubernetes-api/{{< param "version" >}}/#limitrange-v1-core)
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to specify a default value for the memory limit.
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-->
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* 容器可无限制地使用内存。容器可以使用其所在节点所有的可用内存，
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进而可能导致该节点调用 OOM Killer。
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此外，如果发生 OOM Kill，没有资源限制的容器将被杀掉的可行性更大。
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* 运行的容器所在命名空间有默认的内存限制，那么该容器会被自动分配默认限制。
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集群管理员可用使用 [LimitRange](/docs/reference/generated/kubernetes-api/{{< param "version" >}}/#limitrange-v1-core)
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来指定默认的内存限制。
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<!--
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## Motivation for memory requests and limits
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By configuring memory requests and limits for the Containers that run in your
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cluster, you can make efficient use of the memory resources available on your cluster's
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Nodes. By keeping a Pod's memory request low, you give the Pod a good chance of being
|
||
scheduled. By having a memory limit that is greater than the memory request, you accomplish two things:
|
||
-->
|
||
## 内存请求和限制的目的
|
||
|
||
通过为集群中运行的容器配置内存请求和限制，你可以有效利用集群节点上可用的内存资源。
|
||
通过将 Pod 的内存请求保持在较低水平，你可以更好地安排 Pod 调度。
|
||
通过让内存限制大于内存请求，你可以完成两件事：
|
||
|
||
<!--
|
||
* The Pod can have bursts of activity where it makes use of memory that happens to be available.
|
||
* The amount of memory a Pod can use during a burst is limited to some reasonable amount.
|
||
-->
|
||
* Pod 可以进行一些突发活动，从而更好的利用可用内存。
|
||
* Pod 在突发活动期间，可使用的内存被限制为合理的数量。
|
||
|
||
<!--
|
||
## Clean up
|
||
|
||
Delete your namespace. This deletes all the Pods that you created for this task:
|
||
-->
|
||
## 清理
|
||
|
||
删除命名空间。下面的命令会删除你根据这个任务创建的所有 Pod：
|
||
|
||
```shell
|
||
kubectl delete namespace mem-example
|
||
```
|
||
|
||
## {{% heading "whatsnext" %}}
|
||
|
||
<!--
|
||
### For app developers
|
||
|
||
* [Assign CPU Resources to Containers and Pods](/docs/tasks/configure-pod-container/assign-cpu-resource/)
|
||
|
||
* [Configure Quality of Service for Pods](/docs/tasks/configure-pod-container/quality-service-pod/)
|
||
-->
|
||
### 应用开发者扩展阅读
|
||
|
||
* [为容器和 Pod 分配 CPU 资源](/zh/docs/tasks/configure-pod-container/assign-cpu-resource/)
|
||
|
||
* [配置 Pod 的服务质量](/zh/docs/tasks/configure-pod-container/quality-service-pod/)
|
||
|
||
|
||
<!--
|
||
### 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/)
|
||
-->
|
||
### 集群管理员扩展阅读
|
||
|
||
* [为命名空间配置默认的内存请求和限制](/zh/docs/tasks/administer-cluster/manage-resources/memory-default-namespace/)
|
||
* [为命名空间配置默认的 CPU 请求和限制](/zh/docs/tasks/administer-cluster/manage-resources/cpu-default-namespace/)
|
||
* [配置命名空间的最小和最大内存约束](/zh/docs/tasks/administer-cluster/manage-resources/memory-constraint-namespace/)
|
||
* [配置命名空间的最小和最大 CPU 约束](/zh/docs/tasks/administer-cluster/manage-resources/cpu-constraint-namespace/)
|
||
* [为命名空间配置内存和 CPU 配额](/zh/docs/tasks/administer-cluster/manage-resources/quota-memory-cpu-namespace/)
|
||
* [配置命名空间下 Pod 总数](/zh/docs/tasks/administer-cluster/manage-resources/quota-pod-namespace/)
|
||
* [配置 API 对象配额](/zh/docs/tasks/administer-cluster/quota-api-object/)
|
||
|