---
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description: Kubernete教程_Kubernetes组件_PKI 证书和要求
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    content: Kubernetes 教程,Kubernetes 组件,PKI 证书和要求
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# Kubernetes PKI 证书和要求

> 以下内容翻译自自 [PKI certificates and requirements](https://kubernetes.io/docs/setup/best-practices/certificates/)。

Kubernetes 需要 PKI 证书才能进行基于 TLS 的身份验证。当您使用
[kubeadm](/install/install-k8s.html) 安装的 Kubernetes 集群时，kubeadm 将自动生成集群所需的证书。
此外，您也可以使用自己手动生成的证书，这种情况下，您可以将私钥不存储在 API 服务器上，以便让私钥更加安全。此页面说明了 Kubernetes 集群所必需的证书。



<!-- body -->

<!--
## How certificates are used by your cluster

Kubernetes requires PKI for the following operations:
-->
## 集群是如何使用证书的

Kubernetes 需要以下 PKI 才能执行对应的操作：

<!--
* Client certificates for the kubelet to authenticate to the API server
* Server certificate for the API server endpoint
* Client certificates for administrators of the cluster to authenticate to the API server
* Client certificates for the API server to talk to the kubelets
* Client certificate for the API server to talk to etcd
* Client certificate/kubeconfig for the controller manager to talk to the API server
* Client certificate/kubeconfig for the scheduler to talk to the API server.
* Client and server certificates for the [front-proxy](/docs/tasks/extend-kubernetes/configure-aggregation-layer/)
-->
* Kubelet 访问 Apiserver 的客户端证书，用来执行身份认证
* Apiserver 的服务端证书
* 集群管理员访问 apiserver 的客户端证书，当集群管理员使用 kubectl 访问 apiserver 时，用来执行身份认证
* Apiserver 访问 kubelet 的客户端证书，用于 Apiserver 向 kubelet 发起的会话
* Apiserver 访问 etcd 的客户度证书，用于 apiserver 访问 etcd 时的会话
* Kube-controller 访问 apiserver 的客户端证书（存储在对应的 kubeconfig 文件中），当 kube-controller 访问 apiserver 时，用作身份认证
* Kube-scheduler 访问 apiserver 的客户端证书（存储在对应的 kubeconfig 文件中），当 kube-scheduler 访问 apiserver 时，用作身份认证
* [前端代理](https://kubernetes.io/docs/tasks/extend-kubernetes/configure-aggregation-layer/) 的客户端及服务端证书

<!--
`front-proxy` certificates are required only if you run kube-proxy to support [an extension API server](/docs/tasks/access-kubernetes-api/setup-extension-api-server/).
-->
::: tip
通常，只有第三方发行版才需要 [扩展 API 服务器](/learning/k8s-advanced/extend/aggregation.html) 时，才需要用到 `front-proxy` 证书，原生 kubernetes 集群并不需要 `front-proxy` 证书。
:::

<!--
etcd also implements mutual TLS to authenticate clients and peers.
-->
etcd 还需要通过双向 TLS 来对客户端和对其他对等节点进行身份验证。

<!--
## Where certificates are stored

If you install Kubernetes with kubeadm, certificates are stored in `/etc/kubernetes/pki`. All paths in this documentation are relative to that directory.
-->
## 证书的存放位置

如果你的 Kubernetes 集群是通过 kubeadm 安装的，则所有证书都存放在 `/etc/kubernetes/pki` 目录下。本文所有相关的路径都是基于该路径的相对路径。

<!--
## Configure certificates manually

If you don't want kubeadm to generate the required certificates, you can create them in either of the following ways.
-->
## 手动配置证书

如果你不想通过 kubeadm 生成所需要的证书，你可以通过下面两种方式的任何一种来手动创建所需要的证书。

<!--
### Single root CA

You can create a single root CA, controlled by an administrator. This root CA can then create multiple intermediate CAs, and delegate all further creation to Kubernetes itself.
-->
### 单根 CA

集群管理员创建一个单根 CA，并由该 root CA 可以创建多个中间 CA，并由 Kubernetes 进一步创建其他所需的证书。

<!--
Required CAs:

| 路径                    | 默认 CN                    | 描述                             |
|------------------------|---------------------------|----------------------------------|
| ca.crt,key             | kubernetes-ca             | Kubernetes general CA            |
| etcd/ca.crt,key        | etcd-ca                   | For all etcd-related functions   |
| front-proxy-ca.crt,key | kubernetes-front-proxy-ca | For the [front-end proxy](/docs/tasks/extend-kubernetes/configure-aggregation-layer/) |

On top of the above CAs, it is also necessary to get a public/private key pair for service account management, `sa.key` and `sa.pub`.
-->
需要的 CA 如下列表所示：

> 以下路径均相对于目录 `/etc/kubernetes/pki`

| 路径                    | 默认 CN                    | 描述                             |
|------------------------|---------------------------|----------------------------------|
| ca.crt,ca.key                  | kubernetes-ca             | Kubernetes root CA                |
| etcd/ca.crt,etcd/ca.key        | etcd-ca                   | 与 etcd 相关的所有功能              |
| front-proxy-ca.crt,front-proxy-ca.key | kubernetes-front-proxy-ca | 用于 [扩展 API 服务器](/learning/k8s-advanced/extend/aggregation.html) |

除了以上的 CA 之外，还需要提供用于服务账户管理的密钥对， `sa.key` 和 `sa.pub`。

<!--
### All certificates

If you don't wish to copy the CA private keys to your cluster, you can generate all certificates yourself.

Required certificates:
-->
### 所有的证书

如果你不想将 CA 的私钥拷贝至你的集群中，你也可以自己生成全部的证书。

所需的证书如下列表所示：

> 以下路径均相对于目录 `/etc/kubernetes/pki`

| 默认 CN                    | 父级 CA                 | O (位于 Subject 中) | 类型                                   | 主机 (SAN)                                 |
|-------------------------------|---------------------------|----------------|----------------------------------------|---------------------------------------------|
| kube-etcd                     | etcd-ca                   |                | server, client                         | `localhost`, `127.0.0.1`                        |
| kube-etcd-peer                | etcd-ca                   |                | server, client                         | `<hostname>`, `<Host_IP>`, `localhost`, `127.0.0.1` |
| kube-etcd-healthcheck-client  | etcd-ca                   |                | client                                 |                                             |
| kube-apiserver-etcd-client    | etcd-ca                   | system:masters | client                                 |                                             |
| kube-apiserver                | kubernetes-ca             |                | server                                 | `<hostname>`, `<Host_IP>`, `<advertise_IP>`, `其他 IP 或 DNS 名称 [1]` |
| kube-apiserver-kubelet-client | kubernetes-ca             | system:masters | client                                 |                                             |
| front-proxy-client            | kubernetes-front-proxy-ca |                | client                                 |                                             |

<!--
[1]: any other IP or DNS name you contact your cluster on (as used by [kubeadm](/docs/reference/setup-tools/kubeadm/kubeadm/) the load balancer stable IP and/or DNS name, `kubernetes`, `kubernetes.default`, `kubernetes.default.svc`,
`kubernetes.default.svc.cluster`, `kubernetes.default.svc.cluster.local`)

where `kind` maps to one or more of the [x509 key usage](https://godoc.org/k8s.io/api/certificates/v1beta1#KeyUsage) types:
-->
[1]: 访问集群时，可能用到的其他 IP 或 DNS 名称
（例如，为 kube-apiserver 配置的负载均衡所使用的固定 IP 或 DNS 名，`kubernetes`、`kubernetes.default`、`kubernetes.default.svc`、`kubernetes.default.svc.cluster`、`kubernetes.default.svc.cluster.local`）。

其中，`kind` 对应一种或多种类型的 [x509 密钥用途](https://godoc.org/k8s.io/api/certificates/v1beta1#KeyUsage)：

<!--
| kind   | Key usage                                                                       |
|--------|---------------------------------------------------------------------------------|
| server | digital signature, key encipherment, server auth                                |
| client | digital signature, key encipherment, client auth                                |
-->
| kind   | 密钥用途                                                                         |
|--------|---------------------------------------------------------------------------------|
| server | 数字签名、密钥加密、服务端认证                                                       |
| client | 数字签名、密钥加密、客户端认证                                                       |



<!--
Hosts/SAN listed above are the recommended ones for getting a working cluster; if required by a specific setup, it is possible to add additional SANs on all the server certificates.
-->
::: tip
上面列出的 Hosts/SAN 是推荐的配置方式；如果需要特殊安装，则可以在所有服务器证书上添加其他 SAN。
:::

<!--
For kubeadm users only:

* The scenario where you are copying to your cluster CA certificates without private keys is referred as external CA in the kubeadm documentation.
* If you are comparing the above list with a kubeadm generated PKI, please be aware that `kube-etcd`, `kube-etcd-peer` and `kube-etcd-healthcheck-client` certificates
  are not generated in case of external etcd.
-->
::: tip

如果使用 kubeadm 安装集群：

* 安装集群时可以仅将证书的公钥复制到集群，而将集群的私钥由管理员另外保管，这种仅提供公钥的方案被称为外部 CA。
* 如果对比以上列表与 kubeadm 生成的 PKI，将会发现，如果使用外部 etcd，则不会生成 `kube-etcd`、`kube-etcd-peer` 和 `kube-etcd-healthcheck-client` 证书。

:::

<!--
### Certificate paths

Certificates should be placed in a recommended path (as used by [kubeadm](/docs/reference/setup-tools/kubeadm/kubeadm/)). Paths should be specified using the given argument regardless of location.
-->
### 证书路径

下表罗列了证书存放的推荐路径（以便 [kubeadm](https://kubernetes.io/docs/reference/setup-tools/kubeadm/kubeadm/) 使用），同时也罗列了通过什么参数可以自定义证书的存放路径。

| 默认 CN                   | 建议的密钥路径         | 建议的证书路径       | 命令        | 密钥参数               | 证书参数                             |
|------------------------------|------------------------------|-----------------------------|----------------|------------------------------|-------------------------------------------|
| etcd-ca                      |     etcd/ca.key                         | etcd/ca.crt                 | kube-apiserver |                              | --etcd-cafile                             |
| kube-apiserver-etcd-client   | apiserver-etcd-client.key    | apiserver-etcd-client.crt   | kube-apiserver | --etcd-keyfile               | --etcd-certfile                           |
| kubernetes-ca                |    ca.key                          | ca.crt                      | kube-apiserver |                              | --client-ca-file                          |
| kubernetes-ca                |    ca.key                          | ca.crt                      | kube-controller-manager | --cluster-signing-key-file      | --client-ca-file, --root-ca-file, --cluster-signing-cert-file  |
| kube-apiserver               | apiserver.key                | apiserver.crt               | kube-apiserver | --tls-private-key-file       | --tls-cert-file                           |
| kube-apiserver-kubelet-client|     apiserver-kubelet-client.key                         | apiserver-kubelet-client.crt| kube-apiserver | --kubelet-client-key | --kubelet-client-certificate              |
| front-proxy-ca               |     front-proxy-ca.key                         | front-proxy-ca.crt          | kube-apiserver |                              | --requestheader-client-ca-file            |
| front-proxy-ca               |     front-proxy-ca.key                         | front-proxy-ca.crt          | kube-controller-manager |                              | --requestheader-client-ca-file |
| front-proxy-client           | front-proxy-client.key       | front-proxy-client.crt      | kube-apiserver | --proxy-client-key-file      | --proxy-client-cert-file                  |
| etcd-ca                      |         etcd/ca.key                     | etcd/ca.crt                 | etcd           |                              | --trusted-ca-file, --peer-trusted-ca-file |
| kube-etcd                    | etcd/server.key              | etcd/server.crt             | etcd           | --key-file                   | --cert-file                               |
| kube-etcd-peer               | etcd/peer.key                | etcd/peer.crt               | etcd           | --peer-key-file              | --peer-cert-file                          |
| etcd-ca                      |                              | etcd/ca.crt                 | etcdctl    |                              | --cacert                                  |
| kube-etcd-healthcheck-client | etcd/healthcheck-client.key  | etcd/healthcheck-client.crt | etcdctl     | --key                        | --cert                                    |

<!--
Same considerations apply for the service account key pair:
-->
下表罗列了 service account 的密钥对存放路径和自定义路径参数：

| 私钥路径            | 公钥路径            | 命令                 | 参数                             |
|------------------------------|-----------------------------|-------------------------|--------------------------------------|
|  sa.key                      |                             | kube-controller-manager | --service-account-private-key-file              |
|                              | sa.pub                      | kube-apiserver          | --service-account-key-file                  |

<!--
## Configure certificates for user accounts

You must manually configure these administrator account and service accounts:
-->
## 为用户帐户配置证书

如下 ServiceAccount 必须手工配置：

| 文件名                  | 凭据名称                   | 默认 CN                        | O (位于 Subject 中) |
|-------------------------|----------------------------|--------------------------------|---------------------|
| admin.conf              | default-admin              | kubernetes-admin               | system:masters      |
| kubelet.conf            | default-auth               | system:node:`<nodeName>` （参阅注释） | system:nodes |
| controller-manager.conf | default-controller-manager | system:kube-controller-manager |                     |
| scheduler.conf          | default-scheduler          | system:kube-scheduler          |                     |

<!--
The value of `<nodeName>` for `kubelet.conf` **must** match precisely the value of the node name provided by the kubelet as it registers with the apiserver. For further details, read the [Node Authorization](/docs/reference/access-authn-authz/node/).
-->
::: tip 注释
`kubelet.conf` 中 `<nodeName>` 的值 **必须** 与 kubelet 向 apiserver 注册时提供的节点名称的值完全匹配。
有关更多详细信息，请阅读[节点授权](https://kubernetes.io/docs/reference/access-authn-authz/node/)。
:::

<!--
1. For each config, generate an x509 cert/key pair with the given CN and O.

2. Run `kubectl` as follows for each config:
-->
1. 对于每个配置，请使用指定的 CN 和 O 生成 x509 证书/密钥对。

2. 为每个配置运行下面的 `kubectl` 命令：

```shell
KUBECONFIG=<filename> kubectl config set-cluster default-cluster --server=https://<host ip>:6443 --certificate-authority <path-to-kubernetes-ca> --embed-certs
KUBECONFIG=<filename> kubectl config set-credentials <credential-name> --client-key <path-to-key>.pem --client-certificate <path-to-cert>.pem --embed-certs
KUBECONFIG=<filename> kubectl config set-context default-system --cluster default-cluster --user <credential-name>
KUBECONFIG=<filename> kubectl config use-context default-system
```

<!--
These files are used as follows:

| filename                | command                 | comment                                                               |
|-------------------------|-------------------------|-----------------------------------------------------------------------|
| admin.conf              | kubectl                 | Configures administrator user for the cluster                                      |
| kubelet.conf            | kubelet                 | One required for each node in the cluster.                            |
| controller-manager.conf | kube-controller-manager | Must be added to manifest in `manifests/kube-controller-manager.yaml` |
| scheduler.conf          | kube-scheduler          | Must be added to manifest in `manifests/kube-scheduler.yaml`          |
-->
生成的文件用途如下：

| 文件名                   | 命令                     | 说明                                                                  |
|-------------------------|-------------------------|-----------------------------------------------------------------------|
| admin.conf              | kubectl                 | 配置集群的管理员                                                         |
| kubelet.conf            | kubelet                 | 集群中的每个节点都需要一份                                                 |
| controller-manager.conf | kube-controller-manager | 必需添加到 `manifests/kube-controller-manager.yaml` 清单中               |
| scheduler.conf          | kube-scheduler          | 必需添加到 `manifests/kube-scheduler.yaml` 清单中                        |