# 高可用拓扑选项

LLMS index: [llms.txt](/llms.txt)

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reviewers:
- sig-cluster-lifecycle
title: Options for Highly Available Topology
content_type: concept
weight: 50
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This page explains the two options for configuring the topology of your highly available (HA) Kubernetes clusters.
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本页面介绍了配置高可用（HA）Kubernetes 集群拓扑的两个选项。

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You can set up an HA cluster:
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你可以设置 HA 集群：

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- With stacked control plane nodes, where etcd nodes are colocated with control plane nodes
- With external etcd nodes, where etcd runs on separate nodes from the control plane
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- 使用堆叠（stacked）控制平面节点，其中 etcd 节点与控制平面节点共存
- 使用外部 etcd 节点，其中 etcd 在与控制平面不同的节点上运行

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You should carefully consider the advantages and disadvantages of each topology before setting up an HA cluster.
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在设置 HA 集群之前，你应该仔细考虑每种拓扑的优缺点。


<div class="alert alert-info" role="note"><h4 class="alert-heading">说明：</h4><!--
kubeadm bootstraps the etcd cluster statically. Read the etcd
[Clustering Guide](https://github.com/etcd-io/etcd/blob/release-3.4/Documentation/op-guide/clustering.md#static)
for more details.
-->
<p>kubeadm 静态引导 etcd 集群。
阅读 etcd <a href="https://github.com/etcd-io/etcd/blob/release-3.4/Documentation/op-guide/clustering.md#static">集群指南</a>以获得更多详细信息。</p></div>


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## Stacked etcd topology
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## 堆叠（Stacked）etcd 拓扑    {#stacked-etcd-topology}

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A stacked HA cluster is a [topology](https://en.wikipedia.org/wiki/Network_topology) where the distributed
data storage cluster provided by etcd is stacked on top of the cluster formed by the nodes managed by
kubeadm that run control plane components.
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堆叠（Stacked）HA 集群是一种这样的[拓扑](https://zh.wikipedia.org/wiki/%E7%BD%91%E7%BB%9C%E6%8B%93%E6%89%91)，
其中 etcd 分布式数据存储集群堆叠在 kubeadm 管理的控制平面节点上，作为控制平面的一个组件运行。

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Each control plane node runs an instance of the `kube-apiserver`, `kube-scheduler`, and `kube-controller-manager`.
The `kube-apiserver` is exposed to worker nodes using a load balancer.
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每个控制平面节点运行 `kube-apiserver`、`kube-scheduler` 和 `kube-controller-manager` 实例。
`kube-apiserver` 使用负载均衡器暴露给工作节点。

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Each control plane node creates a local etcd member and this etcd member communicates only with
the `kube-apiserver` of this node. The same applies to the local `kube-controller-manager`
and `kube-scheduler` instances.
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每个控制平面节点创建一个本地 etcd 成员（member），这个 etcd 成员只与该节点的 `kube-apiserver` 通信。
这同样适用于本地 `kube-controller-manager` 和 `kube-scheduler` 实例。

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This topology couples the control planes and etcd members on the same nodes. It is simpler to set up than a cluster
with external etcd nodes, and simpler to manage for replication.
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这种拓扑将控制平面和 etcd 成员耦合在同一节点上。相对使用外部 etcd 集群，
设置起来更简单，而且更易于副本管理。

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However, a stacked cluster runs the risk of failed coupling. If one node goes down, both an etcd member and a control
plane instance are lost, and redundancy is compromised. You can mitigate this risk by adding more control plane nodes.
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然而，堆叠集群存在耦合失败的风险。如果一个节点发生故障，则 etcd 成员和控制平面实例都将丢失，
并且冗余会受到影响。你可以通过添加更多控制平面节点来降低此风险。

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You should therefore run a minimum of three stacked control plane nodes for an HA cluster.
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因此，你应该为 HA 集群运行至少三个堆叠的控制平面节点。

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This is the default topology in kubeadm. A local etcd member is created automatically
on control plane nodes when using `kubeadm init` and `kubeadm join --control-plane`.
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这是 kubeadm 中的默认拓扑。当使用 `kubeadm init` 和 `kubeadm join --control-plane` 时，
在控制平面节点上会自动创建本地 etcd 成员。

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![Stacked etcd topology](/images/kubeadm/kubeadm-ha-topology-stacked-etcd.svg)
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![堆叠的 etcd 拓扑](/zh-cn/docs/images/kubeadm-ha-topology-stacked-etcd.svg)

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## External etcd topology
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## 外部 etcd 拓扑    {#external-etcd-topology}

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An HA cluster with external etcd is a [topology](https://en.wikipedia.org/wiki/Network_topology)
where the distributed data storage cluster provided by etcd is external to the cluster formed by
the nodes that run control plane components.
-->
具有外部 etcd 的 HA 集群是一种这样的[拓扑](https://zh.wikipedia.org/wiki/%E7%BD%91%E7%BB%9C%E6%8B%93%E6%89%91)，
其中 etcd 分布式数据存储集群在独立于控制平面节点的其他节点上运行。

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Like the stacked etcd topology, each control plane node in an external etcd topology runs
an instance of the `kube-apiserver`, `kube-scheduler`, and `kube-controller-manager`.
And the `kube-apiserver` is exposed to worker nodes using a load balancer. However,
etcd members run on separate hosts, and each etcd host communicates with the
`kube-apiserver` of each control plane node.
-->
就像堆叠的 etcd 拓扑一样，外部 etcd 拓扑中的每个控制平面节点都会运行
`kube-apiserver`、`kube-scheduler` 和 `kube-controller-manager` 实例。
同样，`kube-apiserver` 使用负载均衡器暴露给工作节点。但是 etcd 成员在不同的主机上运行，
每个 etcd 主机与每个控制平面节点的 `kube-apiserver` 通信。

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This topology decouples the control plane and etcd member. It therefore provides an HA setup where
losing a control plane instance or an etcd member has less impact and does not affect
the cluster redundancy as much as the stacked HA topology.
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这种拓扑结构解耦了控制平面和 etcd 成员。因此它提供了一种 HA 设置，
其中失去控制平面实例或者 etcd 成员的影响较小，并且不会像堆叠的 HA 拓扑那样影响集群冗余。

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However, this topology requires twice the number of hosts as the stacked HA topology.
A minimum of three hosts for control plane nodes and three hosts for etcd nodes are
required for an HA cluster with this topology.
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但此拓扑需要两倍于堆叠 HA 拓扑的主机数量。
具有此拓扑的 HA 集群至少需要三个用于控制平面节点的主机和三个用于 etcd 节点的主机。

<!--
![External etcd topology](/images/kubeadm/kubeadm-ha-topology-external-etcd.svg)
-->
![外部 etcd 拓扑](/zh-cn/docs/images/kubeadm-ha-topology-external-etcd.svg)

## 接下来

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- [Set up a highly available cluster with kubeadm](/docs/setup/production-environment/tools/kubeadm/high-availability/)
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- [使用 kubeadm 设置高可用集群](/zh-cn/docs/setup/production-environment/tools/kubeadm/high-availability/)