192 lines
6.3 KiB
Markdown
192 lines
6.3 KiB
Markdown
---
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title: 管理巨页（HugePage）
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content_type: task
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description: 将巨页作为集群中的可调度资源来配置和管理
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---
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<!--
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reviewers:
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- derekwaynecarr
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title: Manage HugePages
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content_type: task
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description: Configure and manage huge pages as a schedulable resource in a cluster.
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--->
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<!-- overview -->
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{{< feature-state state="stable" >}}
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<!--
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Kubernetes supports the allocation and consumption of pre-allocated huge pages
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by applications in a Pod. This page describes how users can consume huge pages.
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--->
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Kubernetes 支持在 Pod 应用中使用预先分配的巨页。本文描述了用户如何使用巨页，以及当前的限制。
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## {{% heading "prerequisites" %}}
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<!--
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Kubernetes nodes must
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[pre-allocate huge pages](https://www.kernel.org/doc/html/latest/admin-guide/mm/hugetlbpage.html)
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in order for the node to report its huge page capacity.
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A node can pre-allocate huge pages for multiple sizes, for instance,
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the following line in `/etc/default/grub` allocates `2*1GiB` of 1 GiB
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and `512*2 MiB` of 2 MiB pages:
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--->
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为了使节点能够上报巨页容量，Kubernetes
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节点必须[预先分配巨页](https://www.kernel.org/doc/html/latest/admin-guide/mm/hugetlbpage.html)。
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节点能够预先分配多种规格的巨页。例如，在 `/etc/default/grub`
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中的以下这一行分配了 `2*1GiB` 的 1 GiB 页面和 `512*2 MiB` 的 2 MiB 页面。
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```
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GRUB_CMDLINE_LINUX="hugepagesz=1G hugepages=2 hugepagesz=2M hugepages=512"
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```
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<!--
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The nodes will automatically discover and report all huge page resources as
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schedulable resources.
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When you describe the Node, you should see something similar to the following
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in the following in the `Capacity` and `Allocatable` sections:
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-->
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节点将自动发现并报告所有巨页资源作为可调度资源。
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当你描述 Node 时，你应该在 `Capacity` 和 `Allocatable` 节中看到类似以下内容：
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```
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Capacity:
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cpu: ...
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ephemeral-storage: ...
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hugepages-1Gi: 2Gi
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hugepages-2Mi: 1Gi
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memory: ...
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pods: ...
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Allocatable:
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cpu: ...
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ephemeral-storage: ...
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hugepages-1Gi: 2Gi
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hugepages-2Mi: 1Gi
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memory: ...
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pods: ...
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```
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{{< note >}}
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<!--
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For dynamically allocated pages (after boot), the Kubelet needs to be restarted
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for the new allocations to be refrelected.
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-->
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对于动态分配的页面（引导后），kubelet 需要被重新启动才能更新为新的分配。
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{{< /note >}}
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<!-- steps -->
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## API
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<!--
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Huge pages can be consumed via container level resource requirements using the
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resource name `hugepages-<size>`, where `<size>` is the most compact binary
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notation using integer values supported on a particular node. For example, if a
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node supports 2048KiB and 1048576KiB page sizes, it will expose a schedulable
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resources `hugepages-2Mi` and `hugepages-1Gi`. Unlike CPU or memory, huge pages
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do not support overcommit. Note that when requesting hugepage resources, either
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memory or CPU resources must be requested as well.
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A pod may consume multiple huge page sizes in a single pod spec. In this case it
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must use `medium: HugePages-<hugepagesize>` notation for all volume mounts.
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--->
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用户可以通过在容器级别的资源需求中使用资源名称 `hugepages-<size>`
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来使用巨页，其中的 size 是特定节点上支持的以整数值表示的最小二进制单位。
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例如，如果一个节点支持 2048KiB 和 1048576KiB 页面大小，它将公开可调度的资源
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`hugepages-2Mi` 和 `hugepages-1Gi`。与 CPU 或内存不同，巨页不支持过量使用（overcommit）。
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注意，在请求巨页资源时，还必须请求内存或 CPU 资源。
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同一 Pod 的 spec 中可能会消耗不同尺寸的巨页。在这种情况下，它必须对所有挂载卷使用
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`medium: HugePages-<hugepagesize>` 标识。
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```yaml
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apiVersion: v1
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kind: Pod
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metadata:
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name: huge-pages-example
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spec:
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containers:
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- name: example
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image: fedora:latest
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command:
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- sleep
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- inf
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volumeMounts:
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- mountPath: /hugepages-2Mi
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name: hugepage-2mi
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- mountPath: /hugepages-1Gi
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name: hugepage-1gi
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resources:
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limits:
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hugepages-2Mi: 100Mi
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hugepages-1Gi: 2Gi
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memory: 100Mi
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requests:
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memory: 100Mi
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volumes:
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- name: hugepage-2mi
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emptyDir:
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medium: HugePages-2Mi
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- name: hugepage-1gi
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emptyDir:
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medium: HugePages-1Gi
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```
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<!--
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A pod may use `medium: HugePages` only if it requests huge pages of one size.
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-->
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Pod 只有在请求同一大小的巨页时才使用 `medium：HugePages`。
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```yaml
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apiVersion: v1
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kind: Pod
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metadata:
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name: huge-pages-example
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spec:
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containers:
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- name: example
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image: fedora:latest
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command:
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- sleep
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- inf
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volumeMounts:
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- mountPath: /hugepages
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name: hugepage
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resources:
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limits:
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hugepages-2Mi: 100Mi
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memory: 100Mi
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requests:
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memory: 100Mi
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volumes:
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- name: hugepage
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emptyDir:
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medium: HugePages
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```
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<!--
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- Huge page requests must equal the limits. This is the default if limits are
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specified, but requests are not.
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- Huge pages are isolated at a container scope, so each container has own
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limit on their cgroup sandbox as requested in a container spec.
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- EmptyDir volumes backed by huge pages may not consume more huge page memory
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than the pod request.
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- Applications that consume huge pages via `shmget()` with `SHM_HUGETLB` must
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run with a supplemental group that matches `proc/sys/vm/hugetlb_shm_group`.
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- Huge page usage in a namespace is controllable via ResourceQuota similar
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to other compute resources like `cpu` or `memory` using the `hugepages-<size>`
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token.
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--->
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- 巨页的资源请求值必须等于其限制值。该条件在指定了资源限制，而没有指定请求的情况下默认成立。
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- 巨页是被隔离在 Pod 作用域的，因此每个容器在 spec 中都对 cgroup 沙盒有自己的限制。
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- 巨页可用于 EmptyDir 卷，不过 EmptyDir 卷所使用的巨页数量不能够超出 Pod 请求的巨页数量。
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- 通过带有 `SHM_HUGETLB` 的 `shmget()` 使用巨页的应用，必须运行在一个与
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`proc/sys/vm/hugetlb_shm_group` 匹配的补充组下。
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- 通过 ResourceQuota 资源，可以使用 `hugepages-<size>` 标记控制每个命名空间下的巨页使用量，
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类似于使用 `cpu` 或 `memory` 来控制其他计算资源。
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