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---
title: 节点
content_type: concept
weight: 10
---
<!--
reviewers:
- caesarxuchao
- dchen1107
title: Nodes
content_type: concept
weight: 10
-->
<!-- overview -->
<!--
Kubernetes runs your workload by placing containers into Pods to run on _Nodes_.
A node may be a virtual or physical machine, depending on the cluster. Each node
is managed by the
{{< glossary_tooltip text="control plane" term_id="control-plane" >}}
and contains the services necessary to run
{{< glossary_tooltip text="Pods" term_id="pod" >}}.
Typically you have several nodes in a cluster; in a learning or resource-limited
environment, you might have only one node.
The [components](/docs/concepts/overview/components/#node-components) on a node include the
{{< glossary_tooltip text="kubelet" term_id="kubelet" >}}, a
{{< glossary_tooltip text="container runtime" term_id="container-runtime" >}}, and the
{{< glossary_tooltip text="kube-proxy" term_id="kube-proxy" >}}.
-->
Kubernetes 通过将容器放入在节点（Node）上运行的 Pod 中来执行你的工作负载。
节点可以是一个虚拟机或者物理机器，取决于所在的集群配置。
每个节点包含运行 {{< glossary_tooltip text="Pod" term_id="pod" >}} 所需的服务；
这些节点由 {{< glossary_tooltip text="控制面" term_id="control-plane" >}} 负责管理。
通常集群中会有若干个节点；而在一个学习所用或者资源受限的环境中，你的集群中也可能只有一个节点。
节点上的[组件](/zh-cn/docs/concepts/overview/components/#node-components)包括
{{< glossary_tooltip text="kubelet" term_id="kubelet" >}}、
{{< glossary_tooltip text="容器运行时" term_id="container-runtime" >}}以及
{{< glossary_tooltip text="kube-proxy" term_id="kube-proxy" >}}。
<!-- body -->
<!--
## Management
There are two main ways to have Nodes added to the {{< glossary_tooltip text="API server" term_id="kube-apiserver" >}}:
1. The kubelet on a node self-registers to the control plane
2. You (or another human user) manually add a Node object
After you create a Node {{< glossary_tooltip text="object" term_id="object" >}},
or the kubelet on a node self-registers, the control plane checks whether the new Node object is
valid. For example, if you try to create a Node from the following JSON manifest:
-->
## 管理 {#management}
向 {{< glossary_tooltip text="API 服务器" term_id="kube-apiserver" >}}添加节点的方式主要有两种：
1. 节点上的 `kubelet` 向控制面执行自注册；
2. 你（或者别的什么人）手动添加一个 Node 对象。
在你创建了 Node {{< glossary_tooltip text="对象" term_id="object" >}}或者节点上的
`kubelet` 执行了自注册操作之后，控制面会检查新的 Node 对象是否合法。
例如，如果你尝试使用下面的 JSON 对象来创建 Node 对象：
```json
{
"kind": "Node",
"apiVersion": "v1",
"metadata": {
"name": "10.240.79.157",
"labels": {
"name": "my-first-k8s-node"
}
}
}
```
<!--
Kubernetes creates a Node object internally (the representation). Kubernetes checks
that a kubelet has registered to the API server that matches the `metadata.name`
field of the Node. If the node is healthy (i.e. all necessary services are running),
then it is eligible to run a Pod. Otherwise, that node is ignored for any cluster activity
until it becomes healthy.
-->
Kubernetes 会在内部创建一个 Node 对象作为节点的表示。Kubernetes 检查 `kubelet`
向 API 服务器注册节点时使用的 `metadata.name` 字段是否匹配。
如果节点是健康的（即所有必要的服务都在运行中），则该节点可以用来运行 Pod。
否则，直到该节点变为健康之前，所有的集群活动都会忽略该节点。
{{< note >}}
<!--
Kubernetes keeps the object for the invalid Node and continues checking to see whether
it becomes healthy.
You, or a {{< glossary_tooltip term_id="controller" text="controller">}}, must explicitly
delete the Node object to stop that health checking.
-->
Kubernetes 会一直保存着非法节点对应的对象，并持续检查该节点是否已经变得健康。
你，或者某个{{< glossary_tooltip term_id="controller" text="控制器">}}必须显式地删除该
Node 对象以停止健康检查操作。
{{< /note >}}
<!--
The name of a Node object must be a valid
[DNS subdomain name](/docs/concepts/overview/working-with-objects/names#dns-subdomain-names).
-->
Node 对象的名称必须是合法的
[DNS 子域名](/zh-cn/docs/concepts/overview/working-with-objects/names#dns-subdomain-names)。
<!--
### Node name uniqueness
The [name](/docs/concepts/overview/working-with-objects/names#names) identifies a Node. Two Nodes
cannot have the same name at the same time. Kubernetes also assumes that a resource with the same
name is the same object. In case of a Node, it is implicitly assumed that an instance using the
same name will have the same state (e.g. network settings, root disk contents)
and attributes like node labels. This may lead to
inconsistencies if an instance was modified without changing its name. If the Node needs to be
replaced or updated significantly, the existing Node object needs to be removed from API server
first and re-added after the update.
-->
### 节点名称唯一性 {#node-name-uniqueness}
节点的[名称](/zh-cn/docs/concepts/overview/working-with-objects/names#names)用来标识 Node 对象。
没有两个 Node 可以同时使用相同的名称。 Kubernetes 还假定名字相同的资源是同一个对象。
就 Node 而言，隐式假定使用相同名称的实例会具有相同的状态（例如网络配置、根磁盘内容）
和类似节点标签这类属性。这可能在节点被更改但其名称未变时导致系统状态不一致。
如果某个 Node 需要被替换或者大量变更，需要从 API 服务器移除现有的 Node 对象，
之后再在更新之后重新将其加入。
<!--
### Self-registration of Nodes
When the kubelet flag `--register-node` is true (the default), the kubelet will attempt to
register itself with the API server. This is the preferred pattern, used by most distros.
For self-registration, the kubelet is started with the following options:
-->
### 节点自注册 {#self-registration-of-nodes}
当 kubelet 标志 `--register-node` 为 true（默认）时，它会尝试向 API 服务注册自己。
这是首选模式，被绝大多数发行版选用。
对于自注册模式，kubelet 使用下列参数启动：
<!--
- `--kubeconfig` - Path to credentials to authenticate itself to the API server.
- `--cloud-provider` - How to talk to a {{< glossary_tooltip text="cloud provider" term_id="cloud-provider" >}} to read metadata about itself.
- `--register-node` - Automatically register with the API server.
- `--register-with-taints` - Register the node with the given list of {{< glossary_tooltip text="taints" term_id="taint" >}} (comma separated `<key>=<value>:<effect>`).
No-op if `register-node` is false.
- `--node-ip` - IP address of the node.
- `--node-labels` - {{< glossary_tooltip text="Labels" term_id="label" >}} to add when registering the node in the cluster (see label restrictions enforced by the [NodeRestriction admission plugin](/docs/reference/access-authn-authz/admission-controllers/#noderestriction)).
- `--node-status-update-frequency` - Specifies how often kubelet posts node status to master.
-->
- `--kubeconfig` - 用于向 API 服务器执行身份认证所用的凭据的路径。
- `--cloud-provider` - 与某{{< glossary_tooltip text="云驱动" term_id="cloud-provider" >}}
进行通信以读取与自身相关的元数据的方式。
- `--register-node` - 自动向 API 服务注册。
- `--register-with-taints` - 使用所给的{{< glossary_tooltip text="污点" term_id="taint" >}}列表
（逗号分隔的 `<key>=<value>:<effect>`）注册节点。当 `register-node` 为 false 时无效。
- `--node-ip` - 节点 IP 地址。
- `--node-labels` - 在集群中注册节点时要添加的{{< glossary_tooltip text="标签" term_id="label" >}}。
（参见 [NodeRestriction 准入控制插件](/zh-cn/docs/reference/access-authn-authz/admission-controllers/#noderestriction)所实施的标签限制）。
- `--node-status-update-frequency` - 指定 kubelet 向控制面发送状态的频率。
<!--
When the [Node authorization mode](/docs/reference/access-authn-authz/node/) and
[NodeRestriction admission plugin](/docs/reference/access-authn-authz/admission-controllers/#noderestriction) are enabled,
kubelets are only authorized to create/modify their own Node resource.
-->
启用 [Node 鉴权模式](/zh-cn/docs/reference/access-authn-authz/node/)和
[NodeRestriction 准入插件](/zh-cn/docs/reference/access-authn-authz/admission-controllers/#noderestriction)时，
仅授权 `kubelet` 创建或修改其自己的节点资源。
{{< note >}}
<!--
As mentioned in the [Node name uniqueness](#node-name-uniqueness) section,
when Node configuration needs to be updated, it is a good practice to re-register
the node with the API server. For example, if the kubelet being restarted with
the new set of `--node-labels`, but the same Node name is used, the change will
not take an effect, as labels are being set on the Node registration.
-->
正如[节点名称唯一性](#node-name-uniqueness)一节所述，当 Node 的配置需要被更新时，
一种好的做法是重新向 API 服务器注册该节点。例如，如果 kubelet 重启时其 `--node-labels`
是新的值集，但同一个 Node 名称已经被使用，则所作变更不会起作用，
因为节点标签是在 Node 注册时完成的。
<!--
Pods already scheduled on the Node may misbehave or cause issues if the Node
configuration will be changed on kubelet restart. For example, already running
Pod may be tainted against the new labels assigned to the Node, while other
Pods, that are incompatible with that Pod will be scheduled based on this new
label. Node re-registration ensures all Pods will be drained and properly
re-scheduled.
-->
如果在 kubelet 重启期间 Node 配置发生了变化，已经被调度到某 Node 上的 Pod
可能会出现行为不正常或者出现其他问题，例如，已经运行的 Pod
可能通过污点机制设置了与 Node 上新设置的标签相排斥的规则，也有一些其他 Pod，
本来与此 Pod 之间存在不兼容的问题，也会因为新的标签设置而被调到到同一节点。
节点重新注册操作可以确保节点上所有 Pod 都被排空并被正确地重新调度。
{{< /note >}}
<!--
### Manual Node administration
You can create and modify Node objects using
{{< glossary_tooltip text="kubectl" term_id="kubectl" >}}.
When you want to create Node objects manually, set the kubelet flag `--register-node=false`.
You can modify Node objects regardless of the setting of `--register-node`.
For example, you can set labels on an existing Node or mark it unschedulable.
-->
### 手动节点管理 {#manual-node-administration}
你可以使用 {{< glossary_tooltip text="kubectl" term_id="kubectl" >}}
来创建和修改 Node 对象。
如果你希望手动创建节点对象时，请设置 kubelet 标志 `--register-node=false`。
你可以修改 Node 对象（忽略 `--register-node` 设置）。
例如，你可以修改节点上的标签或并标记其为不可调度。
<!--
You can use labels on Nodes in conjunction with node selectors on Pods to control
scheduling. For example, you can constrain a Pod to only be eligible to run on
a subset of the available nodes.
Marking a node as unschedulable prevents the scheduler from placing new pods onto
that Node but does not affect existing Pods on the Node. This is useful as a
preparatory step before a node reboot or other maintenance.
To mark a Node unschedulable, run:
-->
你可以结合使用 Node 上的标签和 Pod 上的选择算符来控制调度。
例如，你可以限制某 Pod 只能在符合要求的节点子集上运行。
如果标记节点为不可调度（unschedulable），将阻止新 Pod 调度到该 Node 之上，
但不会影响任何已经在其上的 Pod。
这是重启节点或者执行其他维护操作之前的一个有用的准备步骤。
要标记一个 Node 为不可调度，执行以下命令：
```shell
kubectl cordon $NODENAME
```
<!--
See [Safely Drain a Node](/docs/tasks/administer-cluster/safely-drain-node/)
for more details.
-->
更多细节参考[安全地腾空节点](/zh-cn/docs/tasks/administer-cluster/safely-drain-node/)。
{{< note >}}
<!--
Pods that are part of a {{< glossary_tooltip term_id="daemonset" >}} tolerate
being run on an unschedulable Node. DaemonSets typically provide node-local services
that should run on the Node even if it is being drained of workload applications.
-->
被 {{< glossary_tooltip term_id="daemonset" text="DaemonSet" >}} 控制器创建的 Pod
能够容忍节点的不可调度属性。
DaemonSet 通常提供节点本地的服务，即使节点上的负载应用已经被腾空，
这些服务也仍需运行在节点之上。
{{< /note >}}
<!--
## Node status
A Node's status contains the following information:
* [Addresses](#addresses)
* [Conditions](#condition)
* [Capacity and Allocatable](#capacity)
* [Info](#info)
-->
## 节点状态 {#node-status}
一个节点的状态包含以下信息:
* [地址（Addresses）](#addresses)
* [状况（Condition）](#condition)
* [容量与可分配（Capacity）](#capacity)
* [信息（Info）](#info)
<!--
You can use `kubectl` to view a Node's status and other details:
-->
你可以使用 `kubectl` 来查看节点状态和其他细节信息：
```shell
kubectl describe node <节点名称>
```
<!-- Each section is described in detail below. -->
下面对每个部分进行详细描述。
<!--
### Addresses
The usage of these fields varies depending on your cloud provider or bare metal configuration.
-->
### 地址 {#addresses}
这些字段的用法取决于你的云服务商或者物理机配置。
<!--
* HostName: The hostname as reported by the node's kernel. Can be overridden via the kubelet `-hostname-override` parameter.
* ExternalIP: Typically the IP address of the node that is externally routable (available from outside the cluster).
* InternalIP: Typichostnameally the IP address of the node that is routable only within the cluster.
-->
* HostName：由节点的内核报告。可以通过 kubelet 的 `--hostname-override` 参数覆盖。
* ExternalIP：通常是节点的可外部路由（从集群外可访问）的 IP 地址。
* InternalIP：通常是节点的仅可在集群内部路由的 IP 地址。
<!--
### Conditions {#condition}
The `conditions` field describes the status of all `Running` nodes. Examples of conditions include:
-->
### 状况 {#condition}
`conditions` 字段描述了所有 `Running` 节点的状况。状况的示例包括：
<!--
{{< table caption = "Node conditions, and a description of when each condition applies." >}}
| Node Condition | Description |
|----------------------|-------------|
| `Ready` | `True` if the node is healthy and ready to accept pods, `False` if the node is not healthy and is not accepting pods, and `Unknown` if the node controller has not heard from the node in the last `node-monitor-grace-period` (default is 40 seconds) |
| `DiskPressure` | `True` if pressure exists on the disk size—that is, if the disk capacity is low; otherwise `False` |
| `MemoryPressure` | `True` if pressure exists on the node memory—that is, if the node memory is low; otherwise `False` |
| `PIDPressure` | `True` if pressure exists on the processes—that is, if there are too many processes on the node; otherwise `False` |
| `NetworkUnavailable` | `True` if the network for the node is not correctly configured, otherwise `False` |
{{< /table >}}
-->
{{< table caption = "节点状况及每种状况适用场景的描述" >}}
| 节点状况 | 描述 |
|----------------|-------------|
| `Ready` | 如节点是健康的并已经准备好接收 Pod 则为 `True`；`False` 表示节点不健康而且不能接收 Pod；`Unknown` 表示节点控制器在最近 `node-monitor-grace-period` 期间（默认 40 秒）没有收到节点的消息 |
| `DiskPressure` | `True` 表示节点存在磁盘空间压力，即磁盘可用量低, 否则为 `False` |
| `MemoryPressure` | `True` 表示节点存在内存压力，即节点内存可用量低，否则为 `False` |
| `PIDPressure` | `True` 表示节点存在进程压力，即节点上进程过多；否则为 `False` |
| `NetworkUnavailable` | `True` 表示节点网络配置不正确；否则为 `False` |
{{< /table >}}
{{< note >}}
<!--
If you use command-line tools to print details of a cordoned Node, the Condition includes
`SchedulingDisabled`. `SchedulingDisabled` is not a Condition in the Kubernetes API; instead,
cordoned nodes are marked Unschedulable in their spec.
-->
如果使用命令行工具来打印已保护（Cordoned）节点的细节，其中的 Condition 字段可能包括
`SchedulingDisabled`。`SchedulingDisabled` 不是 Kubernetes API 中定义的
Condition，被保护起来的节点在其规约中被标记为不可调度（Unschedulable）。
{{< /note >}}
<!--
In the Kubernetes API, a node's condition is represented as part of the `.status`
of the Node resource. For example, the following JSON structure describes a healthy node:
-->
在 Kubernetes API 中，节点的状况表示节点资源中`.status` 的一部分。
例如，以下 JSON 结构描述了一个健康节点：
```json
"conditions": [
{
"type": "Ready",
"status": "True",
"reason": "KubeletReady",
"message": "kubelet is posting ready status",
"lastHeartbeatTime": "2019-06-05T18:38:35Z",
"lastTransitionTime": "2019-06-05T11:41:27Z"
}
]
```
<!--
If the `status` of the Ready condition remains `Unknown` or `False` for longer
than the `pod-eviction-timeout` (an argument passed to the
{{< glossary_tooltip text="kube-controller-manager" term_id="kube-controller-manager"
>}}), then the [node controller](#node-controller) triggers
{{< glossary_tooltip text="API-initiated eviction" term_id="api-eviction" >}}
for all Pods assigned to that node. The default eviction timeout duration is
**five minutes**.
-->
如果 Ready 状况的 `status` 处于 `Unknown` 或者 `False` 状态的时间超过了
`pod-eviction-timeout` 值（一个传递给
{{< glossary_tooltip text="kube-controller-manager" term_id="kube-controller-manager" >}}
的参数），[节点控制器](#node-controller)会对节点上的所有 Pod 触发
{{< glossary_tooltip text="API 发起的驱逐" term_id="api-eviction" >}}。
默认的逐出超时时长为 **5 分钟**。
<!--
In some cases when the node is unreachable, the API server is unable to communicate
with the kubelet on the node. The decision to delete the pods cannot be communicated to
the kubelet until communication with the API server is re-established. In the meantime,
the pods that are scheduled for deletion may continue to run on the partitioned node.
-->
某些情况下，当节点不可达时，API 服务器不能和其上的 kubelet 通信。
删除 Pod 的决定不能传达给 kubelet，直到它重新建立和 API 服务器的连接为止。
与此同时，被计划删除的 Pod 可能会继续在游离的节点上运行。
<!--
The node controller does not force delete pods until it is confirmed that they have stopped
running in the cluster. You can see the pods that might be running on an unreachable node as
being in the `Terminating` or `Unknown` state. In cases where Kubernetes cannot deduce from the
underlying infrastructure if a node has permanently left a cluster, the cluster administrator
may need to delete the node object by hand. Deleting the node object from Kubernetes causes
all the Pod objects running on the node to be deleted from the API server and frees up their
names.
-->
节点控制器在确认 Pod 在集群中已经停止运行前，不会强制删除它们。
你可以看到可能在这些无法访问的节点上运行的 Pod 处于 `Terminating` 或者 `Unknown` 状态。
如果 kubernetes 不能基于下层基础设施推断出某节点是否已经永久离开了集群，
集群管理员可能需要手动删除该节点对象。
从 Kubernetes 删除节点对象将导致 API 服务器删除节点上所有运行的 Pod 对象并释放它们的名字。
<!--
When problems occur on nodes, the Kubernetes control plane automatically creates
[taints](/docs/concepts/scheduling-eviction/taint-and-toleration/) that match the conditions
affecting the node.
The scheduler takes the Node's taints into consideration when assigning a Pod to a Node.
Pods can also have {{< glossary_tooltip text="tolerations" term_id="toleration" >}} that let
them run on a Node even though it has a specific taint.
-->
当节点上出现问题时，Kubernetes 控制面会自动创建与影响节点的状况对应的
[污点](/zh-cn/docs/concepts/scheduling-eviction/taint-and-toleration/)。
调度器在将 Pod 指派到某 Node 时会考虑 Node 上的污点设置。
Pod 也可以设置{{< glossary_tooltip text="容忍度" term_id="toleration" >}}，
以便能够在设置了特定污点的 Node 上运行。
<!--
See [Taint Nodes by Condition](/docs/concepts/scheduling-eviction/taint-and-toleration/#taint-nodes-by-condition)
for more details.
-->
进一步的细节可参阅[根据状况为节点设置污点](/zh-cn/docs/concepts/scheduling-eviction/taint-and-toleration/#taint-nodes-by-condition)。
<!--
### Capacity and Allocatable {#capacity}
Describes the resources available on the node: CPU, memory and the maximum
number of pods that can be scheduled onto the node.
-->
### 容量（Capacity）与可分配（Allocatable） {#capacity}
这两个值描述节点上的可用资源：CPU、内存和可以调度到节点上的 Pod 的个数上限。
<!--
The fields in the capacity block indicate the total amount of resources that a
Node has. The allocatable block indicates the amount of resources on a
Node that is available to be consumed by normal Pods.
-->
`capacity` 块中的字段标示节点拥有的资源总量。
`allocatable` 块指示节点上可供普通 Pod 消耗的资源量。
<!--
You may read more about capacity and allocatable resources while learning how
to [reserve compute resources](/docs/tasks/administer-cluster/reserve-compute-resources/#node-allocatable)
on a Node.
-->
可以在学习如何在节点上[预留计算资源](/zh-cn/docs/tasks/administer-cluster/reserve-compute-resources/#node-allocatable)
的时候了解有关容量和可分配资源的更多信息。
<!--
### Info
Describes general information about the node, such as kernel version, Kubernetes
version (kubelet and kube-proxy version), container runtime details, and which
operating system the node uses.
The kubelet gathers this information from the node and publishes it into
the Kubernetes API.
-->
### 信息（Info） {#info}
Info 指的是节点的一般信息，如内核版本、Kubernetes 版本（`kubelet` 和 `kube-proxy` 版本）、
容器运行时详细信息，以及节点使用的操作系统。
`kubelet` 从节点收集这些信息并将其发布到 Kubernetes API。
<!--
## Heartbeats
Heartbeats, sent by Kubernetes nodes, help your cluster determine the
availability of each node, and to take action when failures are detected.
For nodes there are two forms of heartbeats:
-->
## 心跳 {#heartbeats}
Kubernetes 节点发送的心跳帮助你的集群确定每个节点的可用性，并在检测到故障时采取行动。
对于节点，有两种形式的心跳:
<!--
* updates to the `.status` of a Node
* [Lease](/docs/reference/kubernetes-api/cluster-resources/lease-v1/) objects
within the `kube-node-lease`
{{< glossary_tooltip term_id="namespace" text="namespace">}}.
Each Node has an associated Lease object.
-->
* 更新节点的 `.status`
* `kube-node-lease` {{<glossary_tooltip term_id="namespace" text="名字空间">}}中的
[Lease（租约）](/zh-cn/docs/reference/kubernetes-api/cluster-resources/lease-v1/)对象。
每个节点都有一个关联的 Lease 对象。
<!--
Compared to updates to `.status` of a Node, a Lease is a lightweight resource.
Using Leases for heartbeats reduces the performance impact of these updates
for large clusters.
The kubelet is responsible for creating and updating the `.status` of Nodes,
and for updating their related Leases.
-->
与 Node 的 `.status` 更新相比，Lease 是一种轻量级资源。
使用 Lease 来表达心跳在大型集群中可以减少这些更新对性能的影响。
kubelet 负责创建和更新节点的 `.status`，以及更新它们对应的 Lease。
<!--
- The kubelet updates the node's `.status` either when there is change in status
or if there has been no update for a configured interval. The default interval
for `.status` updates to Nodes is 5 minutes, which is much longer than the 40
second default timeout for unreachable nodes.
- The kubelet creates and then updates its Lease object every 10 seconds
(the default update interval). Lease updates occur independently from
updates to the Node's `.status`. If the Lease update fails, the kubelet retries,
using exponential backoff that starts at 200 milliseconds and capped at 7 seconds.
-->
- 当节点状态发生变化时，或者在配置的时间间隔内没有更新事件时，kubelet 会更新 `.status`。
`.status` 更新的默认间隔为 5 分钟（比节点不可达事件的 40 秒默认超时时间长很多）。
- `kubelet` 会创建并每 10 秒（默认更新间隔时间）更新 Lease 对象。
Lease 的更新独立于 Node 的 `.status` 更新而发生。
如果 Lease 的更新操作失败，kubelet 会采用指数回退机制，从 200 毫秒开始重试，
最长重试间隔为 7 秒钟。
<!--
## Node controller
The node {{< glossary_tooltip text="controller" term_id="controller" >}} is a
Kubernetes control plane component that manages various aspects of nodes.
The node controller has multiple roles in a node's life. The first is assigning a
CIDR block to the node when it is registered (if CIDR assignment is turned on).
-->
## 节点控制器 {#node-controller}
节点{{< glossary_tooltip text="控制器" term_id="controller" >}}是 Kubernetes 控制面组件，
管理节点的方方面面。
节点控制器在节点的生命周期中扮演多个角色。
第一个是当节点注册时为它分配一个 CIDR 区段（如果启用了 CIDR 分配）。
<!--
The second is keeping the node controller's internal list of nodes up to date with
the cloud provider's list of available machines. When running in a cloud
environment and whenever a node is unhealthy, the node controller asks the cloud
provider if the VM for that node is still available. If not, the node
controller deletes the node from its list of nodes.
-->
第二个是保持节点控制器内的节点列表与云服务商所提供的可用机器列表同步。
如果在云环境下运行，只要某节点不健康，节点控制器就会询问云服务是否节点的虚拟机仍可用。
如果不可用，节点控制器会将该节点从它的节点列表删除。
<!--
The third is monitoring the nodes' health. The node controller is
responsible for:
- In the case that a node becomes unreachable, updating the `Ready` condition
in the Node's `.status` field. In this case the node controller sets the
`Ready` condition to `Unknown`.
- If a node remains unreachable: triggering
[API-initiated eviction](/docs/concepts/scheduling-eviction/api-eviction/)
for all of the Pods on the unreachable node. By default, the node controller
waits 5 minutes between marking the node as `Unknown` and submitting
the first eviction request.
By default, the node controller checks the state of each node every 5 seconds.
This period can be configured using the `--node-monitor-period` flag on the
`kube-controller-manager` component.
-->
第三个是监控节点的健康状况。节点控制器负责：
- 在节点不可达的情况下，在 Node 的 `.status` 中更新 `Ready` 状况。
在这种情况下，节点控制器将 NodeReady 状况更新为 `Unknown`。
- 如果节点仍然无法访问：对于不可达节点上的所有 Pod 触发
[API 发起的逐出](/zh-cn/docs/concepts/scheduling-eviction/api-eviction/)操作。
默认情况下，节点控制器在将节点标记为 `Unknown` 后等待 5 分钟提交第一个驱逐请求。
默认情况下，节点控制器每 5 秒检查一次节点状态，可以使用 `kube-controller-manager`
组件上的 `--node-monitor-period` 参数来配置周期。
<!--
### Rate limits on eviction
In most cases, the node controller limits the eviction rate to
`--node-eviction-rate` (default 0.1) per second, meaning it won't evict pods
from more than 1 node per 10 seconds.
-->
### 逐出速率限制 {#rate-limits-on-eviction}
大部分情况下，节点控制器把逐出速率限制在每秒 `--node-eviction-rate` 个（默认为 0.1）。
这表示它每 10 秒钟内至多从一个节点驱逐 Pod。
<!--
The node eviction behavior changes when a node in a given availability zone
becomes unhealthy. The node controller checks what percentage of nodes in the zone
are unhealthy (the `Ready` condition is `Unknown` or `False`) at
the same time:
-->
当一个可用区域（Availability Zone）中的节点变为不健康时，节点的驱逐行为将发生改变。
节点控制器会同时检查可用区域中不健康（`Ready` 状况为 `Unknown` 或 `False`）
的节点的百分比：
<!--
- If the fraction of unhealthy nodes is at least `--unhealthy-zone-threshold`
(default 0.55), then the eviction rate is reduced.
- If the cluster is small (i.e. has less than or equal to
`--large-cluster-size-threshold` nodes - default 50), then evictions are stopped.
- Otherwise, the eviction rate is reduced to `--secondary-node-eviction-rate`
(default 0.01) per second.
-->
- 如果不健康节点的比例超过 `--unhealthy-zone-threshold` （默认为 0.55），
驱逐速率将会降低。
- 如果集群较小（意即小于等于 `--large-cluster-size-threshold` 个节点 - 默认为 50），
驱逐操作将会停止。
- 否则驱逐速率将降为每秒 `--secondary-node-eviction-rate` 个（默认为 0.01）。
<!--
The reason these policies are implemented per availability zone is because one
availability zone might become partitioned from the master while the others remain
connected. If your cluster does not span multiple cloud provider availability zones,
then the eviction mechanism does not take per-zone unavailability into account.
-->
在逐个可用区域中实施这些策略的原因是，
当一个可用区域可能从控制面脱离时其它可用区域可能仍然保持连接。
如果你的集群没有跨越云服务商的多个可用区域，那（整个集群）就只有一个可用区域。
<!--
A key reason for spreading your nodes across availability zones is so that the
workload can be shifted to healthy zones when one entire zone goes down.
Therefore, if all nodes in a zone are unhealthy, then the node controller evicts at
the normal rate of `--node-eviction-rate`. The corner case is when all zones are
completely unhealthy (none of the nodes in the cluster are healthy). In such a
case, the node controller assumes that there is some problem with connectivity
between the control plane and the nodes, and doesn't perform any evictions.
(If there has been an outage and some nodes reappear, the node controller does
evict pods from the remaining nodes that are unhealthy or unreachable).
-->
跨多个可用区域部署你的节点的一个关键原因是当某个可用区域整体出现故障时，
工作负载可以转移到健康的可用区域。
因此，如果一个可用区域中的所有节点都不健康时，节点控制器会以正常的速率
`--node-eviction-rate` 进行驱逐操作。
在所有的可用区域都不健康（也即集群中没有健康节点）的极端情况下，
节点控制器将假设控制面与节点间的连接出了某些问题，它将停止所有驱逐动作
（如果故障后部分节点重新连接，节点控制器会从剩下不健康或者不可达节点中驱逐 Pod）。
<!--
The node controller is also responsible for evicting pods running on nodes with
`NoExecute` taints, unless those pods tolerate that taint.
The node controller also adds {{< glossary_tooltip text="taints" term_id="taint" >}}
corresponding to node problems like node unreachable or not ready. This means
that the scheduler won't place Pods onto unhealthy nodes.
-->
节点控制器还负责驱逐运行在拥有 `NoExecute` 污点的节点上的 Pod，
除非这些 Pod 能够容忍此污点。
节点控制器还负责根据节点故障（例如节点不可访问或没有就绪）
为其添加{{< glossary_tooltip text="污点" term_id="taint" >}}。
这意味着调度器不会将 Pod 调度到不健康的节点上。
<!--
## Resource capacity tracking {#node-capacity}
Node objects track information about the Node's resource capacity (for example: the amount
of memory available, and the number of CPUs).
Nodes that [self register](#self-registration-of-nodes) report their capacity during
registration. If you [manually](#manual-node-administration) add a Node, then
you need to set the node's capacity information when you add it.
-->
### 资源容量跟踪 {#node-capacity}
Node 对象会跟踪节点上资源的容量（例如可用内存和 CPU 数量）。
通过[自注册](#self-registration-of-nodes)机制生成的 Node 对象会在注册期间报告自身容量。
如果你[手动](#manual-node-administration)添加了 Node，
你就需要在添加节点时手动设置节点容量。
<!--
The Kubernetes {{< glossary_tooltip text="scheduler" term_id="kube-scheduler" >}} ensures that
there are enough resources for all the pods on a node. The scheduler checks that the sum
of the requests of containers on the node is no greater than the node capacity.
The sum of requests includes all containers started by the kubelet, but excludes any
containers started directly by the container runtime, and also excludes any
process running outside of the kubelet's control.
-->
Kubernetes {{< glossary_tooltip text="调度器" term_id="kube-scheduler" >}}
保证节点上有足够的资源供其上的所有 Pod 使用。
它会检查节点上所有容器的请求的总和不会超过节点的容量。
总的请求包括由 kubelet 启动的所有容器，但不包括由容器运行时直接启动的容器，
也不包括不受 `kubelet` 控制的其他进程。
{{< note >}}
<!--
If you want to explicitly reserve resources for non-Pod processes, follow this tutorial to
[reserve resources for system daemons](/docs/tasks/administer-cluster/reserve-compute-resources/#system-reserved).
-->
如果要为非 Pod 进程显式保留资源。
请参考[为系统守护进程预留资源](/zh-cn/docs/tasks/administer-cluster/reserve-compute-resources/#system-reserved)。
{{< /note >}}
<!--
## Node topology
-->
## 节点拓扑 {#node-topology}
{{< feature-state state="beta" for_k8s_version="v1.18" >}}
<!--
If you have enabled the `TopologyManager`
[feature gate](/docs/reference/command-line-tools-reference/feature-gates/), then
the kubelet can use topology hints when making resource assignment decisions.
See [Control Topology Management Policies on a Node](/docs/tasks/administer-cluster/topology-manager/)
for more information.
-->
如果启用了 `TopologyManager` [特性门控](/zh-cn/docs/reference/command-line-tools-reference/feature-gates/)，
`kubelet` 可以在作出资源分配决策时使用拓扑提示。
参考[控制节点上拓扑管理策略](/zh-cn/docs/tasks/administer-cluster/topology-manager/)了解详细信息。
<!--
## Graceful node shutdown {#graceful-node-shutdown}
-->
## 节点体面关闭 {#graceful-node-shutdown}
{{< feature-state state="beta" for_k8s_version="v1.21" >}}
<!--
The kubelet attempts to detect node system shutdown and terminates pods running on the node.
Kubelet ensures that pods follow the normal
[pod termination process](/docs/concepts/workloads/pods/pod-lifecycle/#pod-termination)
during the node shutdown.
-->
kubelet 会尝试检测节点系统关闭事件并终止在节点上运行的所有 Pod。
在节点终止期间，kubelet 保证 Pod 遵从常规的
[Pod 终止流程](/zh-cn/docs/concepts/workloads/pods/pod-lifecycle/#pod-termination)。
<!--
The graceful node shutdown feature depends on systemd since it takes advantage of
[systemd inhibitor locks](https://www.freedesktop.org/wiki/Software/systemd/inhibit/) to
delay the node shutdown with a given duration.
-->
节点体面关闭特性依赖于 systemd，因为它要利用
[systemd 抑制器锁](https://www.freedesktop.org/wiki/Software/systemd/inhibit/)机制，
在给定的期限内延迟节点关闭。
<!--
Graceful node shutdown is controlled with the `GracefulNodeShutdown`
[feature gate](/docs/reference/command-line-tools-reference/feature-gates/) which is
enabled by default in 1.21.
-->
节点体面关闭特性受 `GracefulNodeShutdown`
[特性门控](/zh-cn/docs/reference/command-line-tools-reference/feature-gates/)控制，
在 1.21 版本中是默认启用的。
<!--
Note that by default, both configuration options described below,
`ShutdownGracePeriod` and `ShutdownGracePeriodCriticalPods` are set to zero,
thus not activating the graceful node shutdown functionality.
To activate the feature, the two kubelet config settings should be configured appropriately and set to non-zero values.
-->
注意，默认情况下，下面描述的两个配置选项，`shutdownGracePeriod` 和
`shutdownGracePeriodCriticalPods` 都是被设置为 0 的，因此不会激活节点体面关闭功能。
要激活此功能特性，这两个 kubelet 配置选项要适当配置，并设置为非零值。
<!--
During a graceful shutdown, kubelet terminates pods in two phases:
1. Terminate regular pods running on the node.
2. Terminate [critical pods](/docs/tasks/administer-cluster/guaranteed-scheduling-critical-addon-pods/#marking-pod-as-critical) running on the node.
-->
在体面关闭节点过程中，kubelet 分两个阶段来终止 Pod：
1. 终止在节点上运行的常规 Pod。
2. 终止在节点上运行的[关键 Pod](/zh-cn/docs/tasks/administer-cluster/guaranteed-scheduling-critical-addon-pods/#marking-pod-as-critical)。
<!--
Graceful Node Shutdown feature is configured with two [`KubeletConfiguration`](/docs/tasks/administer-cluster/kubelet-config-file/) options:
* `ShutdownGracePeriod`:
* Specifies the total duration that the node should delay the shutdown by. This is the total grace period for pod termination for both regular and [critical pods](/docs/tasks/administer-cluster/guaranteed-scheduling-critical-addon-pods/#marking-pod-as-critical).
* `ShutdownGracePeriodCriticalPods`:
* Specifies the duration used to terminate [critical pods](/docs/tasks/administer-cluster/guaranteed-scheduling-critical-addon-pods/#marking-pod-as-critical) during a node shutdown. This value should be less than `ShutdownGracePeriod`.
-->
节点体面关闭的特性对应两个
[`KubeletConfiguration`](/zh-cn/docs/tasks/administer-cluster/kubelet-config-file/) 选项：
* `shutdownGracePeriod`：
* 指定节点应延迟关闭的总持续时间。此时间是 Pod 体面终止的时间总和，不区分常规 Pod
还是[关键 Pod](/zh-cn/docs/tasks/administer-cluster/guaranteed-scheduling-critical-addon-pods/#marking-pod-as-critical)。
* `shutdownGracePeriodCriticalPods`：
* 在节点关闭期间指定用于终止[关键 Pod](/zh-cn/docs/tasks/administer-cluster/guaranteed-scheduling-critical-addon-pods/#marking-pod-as-critical)
的持续时间。该值应小于 `shutdownGracePeriod`。
<!--
For example, if `ShutdownGracePeriod=30s`, and
`ShutdownGracePeriodCriticalPods=10s`, kubelet will delay the node shutdown by
30 seconds. During the shutdown, the first 20 (30-10) seconds would be reserved
for gracefully terminating normal pods, and the last 10 seconds would be
reserved for terminating [critical pods](/docs/tasks/administer-cluster/guaranteed-scheduling-critical-addon-pods/#marking-pod-as-critical).
-->
例如，如果设置了 `shutdownGracePeriod=30s` 和 `shutdownGracePeriodCriticalPods=10s`，
则 kubelet 将延迟 30 秒关闭节点。
在关闭期间，将保留前 20（30 - 10）秒用于体面终止常规 Pod，
而保留最后 10 秒用于终止[关键 Pod](/zh-cn/docs/tasks/administer-cluster/guaranteed-scheduling-critical-addon-pods/#marking-pod-as-critical)。
<!--
When pods were evicted during the graceful node shutdown, they are marked as failed.
Running `kubectl get pods` shows the status of the the evicted pods as `Shutdown`.
And `kubectl describe pod` indicates that the pod was evicted because of node shutdown:
-->
{{< note >}}
当 Pod 在正常节点关闭期间被驱逐时，它们会被标记为已经失败（Failed）。
运行 `kubectl get pods` 时，被驱逐的 Pod 的状态显示为 `Shutdown`。
并且 `kubectl describe pod` 表示 Pod 因节点关闭而被驱逐：
```
Reason: Terminated
Message: Pod was terminated in response to imminent node shutdown.
```
{{< /note >}}
<!--
## Non Graceful node shutdown {#non-graceful-node-shutdown}
-->
## 节点非体面关闭 {#non-graceful-node-shutdown}
{{< feature-state state="alpha" for_k8s_version="v1.24" >}}
<!--
A node shutdown action may not be detected by kubelet's Node Shutdown Manager,
either because the command does not trigger the inhibitor locks mechanism used by
kubelet or because of a user error, i.e., the ShutdownGracePeriod and
ShutdownGracePeriodCriticalPods are not configured properly. Please refer to above
section [Graceful Node Shutdown](#graceful-node-shutdown) for more details.
-->
节点关闭的操作可能无法被 kubelet 的节点关闭管理器检测到，
是因为该命令不会触发 kubelet 所使用的抑制锁定机制，或者是因为用户错误的原因，
即 ShutdownGracePeriod 和 ShutdownGracePeriodCriticalPod 配置不正确。
请参考以上[节点体面关闭](#graceful-node-shutdown)部分了解更多详细信息。
<!--
When a node is shutdown but not detected by kubelet's Node Shutdown Manager, the pods
that are part of a StatefulSet will be stuck in terminating status on
the shutdown node and cannot move to a new running node. This is because kubelet on
the shutdown node is not available to delete the pods so the StatefulSet cannot
create a new pod with the same name. If there are volumes used by the pods, the
VolumeAttachments will not be deleted from the original shutdown node so the volumes
used by these pods cannot be attached to a new running node. As a result, the
application running on the StatefulSet cannot function properly. If the original
shutdown node comes up, the pods will be deleted by kubelet and new pods will be
created on a different running node. If the original shutdown node does not come up,
these pods will be stuck in terminating status on the shutdown node forever.
-->
当某节点关闭但 kubelet 的节点关闭管理器未检测到这一事件时，
在那个已关闭节点上、属于 StatefulSet 的 Pod 将停滞于终止状态，并且不能移动到新的运行节点上。
这是因为已关闭节点上的 kubelet 已不存在，亦无法删除 Pod，
因此 StatefulSet 无法创建同名的新 Pod。
如果 Pod 使用了卷，则 VolumeAttachments 不会从原来的已关闭节点上删除，
因此这些 Pod 所使用的卷也无法挂接到新的运行节点上。
所以，那些以 StatefulSet 形式运行的应用无法正常工作。
如果原来的已关闭节点被恢复，kubelet 将删除 Pod，新的 Pod 将被在不同的运行节点上创建。
如果原来的已关闭节点没有被恢复，那些在已关闭节点上的 Pod 将永远滞留在终止状态。
<!--
To mitigate the above situation, a user can manually add the taint `node
kubernetes.io/out-of-service` with either `NoExecute` or `NoSchedule` effect to
a Node marking it out-of-service.
If the `NodeOutOfServiceVolumeDetach` [feature gate](/docs/reference/
command-line-tools-reference/feature-gates/) is enabled on
`kube-controller-manager`, and a Node is marked out-of-service with this taint, the
pods on the node will be forcefully deleted if there are no matching tolerations on
it and volume detach operations for the pods terminating on the node will happen
immediately. This allows the Pods on the out-of-service node to recover quickly on a
different node.
-->
为了缓解上述情况，用户可以手动将具有 `NoExecute` 或 `NoSchedule` 效果的
`node kubernetes.io/out-of-service` 污点添加到节点上，标记其无法提供服务。
如果在 `kube-controller-manager` 上启用了 `NodeOutOfServiceVolumeDetach`
[特性门控](/zh-cn/docs/reference/command-line-tools-reference/feature-gates/)，
并且节点被通过污点标记为无法提供服务，如果节点 Pod 上没有设置对应的容忍度，
那么这样的 Pod 将被强制删除，并且该在节点上被终止的 Pod 将立即进行卷分离操作。
这样就允许那些在无法提供服务节点上的 Pod 能在其他节点上快速恢复。
<!--
During a non-graceful shutdown, Pods are terminated in the two phases:
1. Force delete the Pods that do not have matching `out-of-service` tolerations.
2. Immediately perform detach volume operation for such pods.
-->
在非体面关闭期间，Pod 分两个阶段终止：
1. 强制删除没有匹配的 `out-of-service` 容忍度的 Pod。
2. 立即对此类 Pod 执行分离卷操作。
<!--
{{< note >}}
- Before adding the taint `node.kubernetes.io/out-of-service` , it should be verified
that the node is already in shutdown or power off state (not in the middle of
restarting).
- The user is required to manually remove the out-of-service taint after the pods are
moved to a new node and the user has checked that the shutdown node has been
recovered since the user was the one who originally added the taint.
{{< /note >}}
-->
{{< note >}}
- 在添加 `node.kubernetes.io/out-of-service` 污点之前，应该验证节点已经处于关闭或断电状态（而不是在重新启动中）。
- 将 Pod 移动到新节点后，用户需要手动移除停止服务的污点，并且用户要检查关闭节点是否已恢复，因为该用户是最初添加污点的用户。
{{< /note >}}
<!--
### Pod Priority based graceful node shutdown {#pod-priority-graceful-node-shutdown}
-->
### 基于 Pod 优先级的节点体面关闭 {#pod-priority-graceful-node-shutdown}
{{< feature-state state="alpha" for_k8s_version="v1.23" >}}
<!--
To provide more flexibility during graceful node shutdown around the ordering
of pods during shutdown, graceful node shutdown honors the PriorityClass for
Pods, provided that you enabled this feature in your cluster. The feature
allows cluster administers to explicitly define the ordering of pods
during graceful node shutdown based on
[priority classes](/docs/concepts/scheduling-eviction/pod-priority-preemption/#priorityclass).
-->
为了在节点体面关闭期间提供更多的灵活性，尤其是处理关闭期间的 Pod 排序问题，
节点体面关闭机制能够关注 Pod 的 PriorityClass 设置，前提是你已经在集群中启用了此功能特性。
此功能特性允许集群管理员基于 Pod
的[优先级类（Priority Class）](/zh-cn/docs/concepts/scheduling-eviction/pod-priority-preemption/#priorityclass)
显式地定义节点体面关闭期间 Pod 的处理顺序。
<!--
The [Graceful Node Shutdown](#graceful-node-shutdown) feature, as described
above, shuts down pods in two phases, non-critical pods, followed by critical
pods. If additional flexibility is needed to explicitly define the ordering of
pods during shutdown in a more granular way, pod priority based graceful
shutdown can be used.
-->
前文所述的[节点体面关闭](#graceful-node-shutdown)特性能够分两个阶段关闭 Pod，
首先关闭的是非关键的 Pod，之后再处理关键 Pod。
如果需要显式地以更细粒度定义关闭期间 Pod 的处理顺序，需要一定的灵活度，
这时可以使用基于 Pod 优先级的体面关闭机制。
<!--
When graceful node shutdown honors pod priorities, this makes it possible to do
graceful node shutdown in multiple phases, each phase shutting down a
particular priority class of pods. The kubelet can be configured with the exact
phases and shutdown time per phase.
-->
当节点体面关闭能够处理 Pod 优先级时，节点体面关闭的处理可以分为多个阶段，
每个阶段关闭特定优先级类的 Pod。kubelet 可以被配置为按确切的阶段处理 Pod，
且每个阶段可以独立设置关闭时间。
<!--
Assuming the following custom pod
[priority classes](/docs/concepts/scheduling-eviction/pod-priority-preemption/#priorityclass)
in a cluster,
-->
假设集群中存在以下自定义的 Pod
[优先级类](/zh-cn/docs/concepts/scheduling-eviction/pod-priority-preemption/#priorityclass)。
| Pod 优先级类名称 | Pod 优先级类数值 |
|-------------------------|------------------------|
|`custom-class-a` | 100000 |
|`custom-class-b` | 10000 |
|`custom-class-c` | 1000 |
|`regular/unset` | 0 |
<!--
Within the [kubelet configuration](/docs/reference/config-api/kubelet-config.v1beta1/#kubelet-config-k8s-io-v1beta1-KubeletConfiguration)
the settings for `shutdownGracePeriodByPodPriority` could look like:
-->
在 [kubelet 配置](/zh-cn/docs/reference/config-api/kubelet-config.v1beta1/#kubelet-config-k8s-io-v1beta1-KubeletConfiguration)中，
`shutdownGracePeriodByPodPriority` 可能看起来是这样：
| Pod 优先级类数值 | 关闭期限 |
|------------------------|-----------|
| 100000 | 10 秒 |
| 10000 | 180 秒 |
| 1000 | 120 秒 |
| 0 | 60 秒 |
<!--
The corresponding kubelet config YAML configuration would be:
-->
对应的 kubelet 配置 YAML 将会是：
```yaml
shutdownGracePeriodByPodPriority:
- priority: 100000
shutdownGracePeriodSeconds: 10
- priority: 10000
shutdownGracePeriodSeconds: 180
- priority: 1000
shutdownGracePeriodSeconds: 120
- priority: 0
shutdownGracePeriodSeconds: 60
```
<!--
The above table implies that any pod with `priority` value >= 100000 will get
just 10 seconds to stop, any pod with value >= 10000 and < 100000 will get 180
seconds to stop, any pod with value >= 1000 and < 10000 will get 120 seconds to stop.
Finally, all other pods will get 60 seconds to stop.
One doesn't have to specify values corresponding to all of the classes. For
example, you could instead use these settings:
-->
上面的表格表明，所有 `priority` 值大于等于 100000 的 Pod 会得到 10 秒钟期限停止，
所有 `priority` 值介于 10000 和 100000 之间的 Pod 会得到 180 秒钟期限停止，
所有 `priority` 值介于 1000 和 10000 之间的 Pod 会得到 120 秒钟期限停止，
所有其他 Pod 将获得 60 秒的时间停止。
用户不需要为所有的优先级类都设置数值。例如，你也可以使用下面这种配置：
| Pod 优先级类数值 | 关闭期限 |
|------------------------|-----------|
| 100000 | 300 秒 |
| 1000 | 120 秒 |
| 0 | 60 秒 |
<!--
In the above case, the pods with `custom-class-b` will go into the same bucket
as `custom-class-c` for shutdown.
If there are no pods in a particular range, then the kubelet does not wait
for pods in that priority range. Instead, the kubelet immediately skips to the
next priority class value range.
-->
在上面这个场景中，优先级类为 `custom-class-b` 的 Pod 会与优先级类为 `custom-class-c`
的 Pod 在关闭时按相同期限处理。
如果在特定的范围内不存在 Pod，则 kubelet 不会等待对应优先级范围的 Pod。
kubelet 会直接跳到下一个优先级数值范围进行处理。
<!--
If this feature is enabled and no configuration is provided, then no ordering
action will be taken.
Using this feature requires enabling the `GracefulNodeShutdownBasedOnPodPriority`
[feature gate](/docs/reference/command-line-tools-reference/feature-gates/)
, and setting `ShutdownGracePeriodByPodPriority` in the
[kubelet config](/docs/reference/config-api/kubelet-config.v1beta1/)
to the desired configuration containing the pod priority class values and
their respective shutdown periods.
-->
如果此功能特性被启用，但没有提供配置数据，则不会出现排序操作。
使用此功能特性需要启用 `GracefulNodeShutdownBasedOnPodPriority`
[特性门控](/zh-cn/docs/reference/command-line-tools-reference/feature-gates/)，
并将 [kubelet 配置](/zh-cn/docs/reference/config-api/kubelet-config.v1beta1/)
中的 `shutdownGracePeriodByPodPriority` 设置为期望的配置，
其中包含 Pod 的优先级类数值以及对应的关闭期限。
<!--
{{< note >}}
The ability to take Pod priority into account during graceful node shutdown was introduced
as an Alpha feature in Kubernetes v1.23. In Kubernetes {{< skew currentVersion >}}
the feature is Beta and is enabled by default.
{{< /note >}}
-->
{{< note >}}
在节点体面关闭期间考虑 Pod 优先级的能力是作为 Kubernetes v1.23 中的 Alpha 功能引入的。
在 Kubernetes {{< skew currentVersion >}} 中该功能是 Beta 版，默认启用。
{{< /note >}}
<!--
Metrics `graceful_shutdown_start_time_seconds` and `graceful_shutdown_end_time_seconds`
are emitted under the kubelet subsystem to monitor node shutdowns.
-->
kubelet 子系统中会生成 `graceful_shutdown_start_time_seconds` 和
`graceful_shutdown_end_time_seconds` 度量指标以便监视节点关闭行为。
<!--
## Swap memory management {#swap-memory}
-->
## 交换内存管理 {#swap-memory}
{{< feature-state state="alpha" for_k8s_version="v1.22" >}}
<!--
Prior to Kubernetes 1.22, nodes did not support the use of swap memory, and a
kubelet would by default fail to start if swap was detected on a node. In 1.22
onwards, swap memory support can be enabled on a per-node basis.
-->
在 Kubernetes 1.22 之前，节点不支持使用交换内存，并且默认情况下，
如果在节点上检测到交换内存配置，kubelet 将无法启动。
在 1.22 以后，可以逐个节点地启用交换内存支持。
<!--
To enable swap on a node, the `NodeSwap` feature gate must be enabled on
the kubelet, and the `--fail-swap-on` command line flag or `failSwapOn`
[configuration setting](/docs/reference/config-api/kubelet-config.v1beta1/#kubelet-config-k8s-io-v1beta1-KubeletConfiguration)
must be set to false.
-->
要在节点上启用交换内存，必须启用kubelet 的 `NodeSwap` 特性门控，
同时使用 `--fail-swap-on` 命令行参数或者将 `failSwapOn`
[配置](/zh-cn/docs/reference/config-api/kubelet-config.v1beta1/#kubelet-config-k8s-io-v1beta1-KubeletConfiguration)设置为 false。
<!--
A user can also optionally configure `memorySwap.swapBehavior` in order to
specify how a node will use swap memory. For example,
-->
用户还可以选择配置 `memorySwap.swapBehavior` 以指定节点使用交换内存的方式。例如:
```yaml
memorySwap:
swapBehavior: LimitedSwap
```
<!--
The available configuration options for `swapBehavior` are:
- `LimitedSwap`: Kubernetes workloads are limited in how much swap they can
use. Workloads on the node not managed by Kubernetes can still swap.
- `UnlimitedSwap`: Kubernetes workloads can use as much swap memory as they
request, up to the system limit.
-->
可用的 `swapBehavior` 的配置选项有：
- `LimitedSwap`：Kubernetes 工作负载的交换内存会受限制。
不受 Kubernetes 管理的节点上的工作负载仍然可以交换。
- `UnlimitedSwap`：Kubernetes 工作负载可以使用尽可能多的交换内存请求，
一直到达到系统限制为止。
<!--
If configuration for `memorySwap` is not specified and the feature gate is
enabled, by default the kubelet will apply the same behaviour as the
`LimitedSwap` setting.
The behaviour of the `LimitedSwap` setting depends if the node is running with
v1 or v2 of control groups (also known as "cgroups"):
-->
如果启用了特性门控但是未指定 `memorySwap` 的配置，默认情况下 kubelet 将使用
`LimitedSwap` 设置。
`LimitedSwap` 这种设置的行为取决于节点运行的是 v1 还是 v2 的控制组（也就是 `cgroups`）：
<!--
- **cgroupsv1:** Kubernetes workloads can use any combination of memory and
swap, up to the pod's memory limit, if set.
- **cgroupsv2:** Kubernetes workloads cannot use swap memory.
-->
- **cgroupsv1:** Kubernetes 工作负载可以使用内存和交换，上限为 Pod 的内存限制值（如果设置了的话）。
- **cgroupsv2:** Kubernetes 工作负载不能使用交换内存。
<!--
For more information, and to assist with testing and provide feedback, please
see [KEP-2400](https://github.com/kubernetes/enhancements/issues/2400) and its
[design proposal](https://github.com/kubernetes/enhancements/blob/master/keps/sig-node/2400-node-swap/README.md).
-->
如需更多信息以及协助测试和提供反馈，请参见
[KEP-2400](https://github.com/kubernetes/enhancements/issues/2400)
及其[设计提案](https://github.com/kubernetes/enhancements/blob/master/keps/sig-node/2400-node-swap/README.md)。
## {{% heading "whatsnext" %}}
<!--
* Learn about the [components](/docs/concepts/overview/components/#node-components) that make up a node.
* Read the [API definition for Node](/docs/reference/generated/kubernetes-api/{{< param "version" >}}/#node-v1-core).
* Read the [Node](https://git.k8s.io/design-proposals-archive/architecture/architecture.md#the-kubernetes-node)
section of the architecture design document.
* Read about [taints and tolerations](/docs/concepts/scheduling-eviction/taint-and-toleration/).
-->
* 进一步了解节点[组件](/zh-cn/docs/concepts/overview/components/#node-components)。
* 阅读 [Node 的 API 定义](/docs/reference/generated/kubernetes-api/{{< param "version" >}}/#node-v1-core)。
* 阅读架构设计文档中有关
[Node](https://git.k8s.io/design-proposals-archive/architecture/architecture.md#the-kubernetes-node)
的章节。
* 了解[污点和容忍度](/zh-cn/docs/concepts/scheduling-eviction/taint-and-toleration/)。
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