277 lines
18 KiB
Markdown
277 lines
18 KiB
Markdown
---
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layout: LearningLayout
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description: Kubernete教程_Kubernetes组件_PKI 证书和要求
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meta:
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- name: keywords
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content: Kubernetes 教程,Kubernetes 组件,PKI 证书和要求
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---
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# Kubernetes PKI 证书和要求
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> 以下内容翻译自自 [PKI certificates and requirements](https://kubernetes.io/docs/setup/best-practices/certificates/)。
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Kubernetes 需要 PKI 证书才能进行基于 TLS 的身份验证。当您使用
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[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。
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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。
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<!-- body -->
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<!--
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## How certificates are used by your cluster
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Kubernetes requires PKI for the following operations:
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-->
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## 集群是如何使用证书的
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Kubernetes 需要以下 PKI 才能执行对应的操作：
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<!--
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* Client certificates for the kubelet to authenticate to the API server
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* Server certificate for the API server endpoint
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* Client certificates for administrators of the cluster to authenticate to the API server
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* Client certificates for the API server to talk to the kubelets
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* Client certificate for the API server to talk to etcd
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* Client certificate/kubeconfig for the controller manager to talk to the API server
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* Client certificate/kubeconfig for the scheduler to talk to the API server.
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* Client and server certificates for the [front-proxy](/docs/tasks/extend-kubernetes/configure-aggregation-layer/)
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-->
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* Kubelet 访问 Apiserver 的客户端证书，用来执行身份认证
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* Apiserver 的服务端证书
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* 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
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* Apiserver 访问 kubelet 的客户端证书，用于 Apiserver 向 kubelet 发起的会话
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* Apiserver 访问 etcd 的客户度证书，用于 apiserver 访问 etcd 时的会话
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* 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
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* 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
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* [前端代理](https://kubernetes.io/docs/tasks/extend-kubernetes/configure-aggregation-layer/) 的客户端及服务端证书
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<!--
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`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/).
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-->
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::: tip
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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。
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:::
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<!--
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etcd also implements mutual TLS to authenticate clients and peers.
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-->
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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。
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<!--
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## Where certificates are stored
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If you install Kubernetes with kubeadm, certificates are stored in `/etc/kubernetes/pki`. All paths in this documentation are relative to that directory.
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-->
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## 证书的存放位置
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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。
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<!--
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## Configure certificates manually
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If you don't want kubeadm to generate the required certificates, you can create them in either of the following ways.
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-->
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## 手动配置证书
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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。
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<!--
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### Single root CA
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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.
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-->
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### 单根 CA
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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。
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<!--
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Required CAs:
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| 路径 | 默认 CN | 描述 |
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|------------------------|---------------------------|----------------------------------|
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| ca.crt,key | kubernetes-ca | Kubernetes general CA |
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| etcd/ca.crt,key | etcd-ca | For all etcd-related functions |
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| front-proxy-ca.crt,key | kubernetes-front-proxy-ca | For the [front-end proxy](/docs/tasks/extend-kubernetes/configure-aggregation-layer/) |
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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`.
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-->
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需要的 CA 如下列表所示：
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> 以下路径均相对于目录 `/etc/kubernetes/pki`
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| 路径 | 默认 CN | 描述 |
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|------------------------|---------------------------|----------------------------------|
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| ca.crt,ca.key | kubernetes-ca | Kubernetes root CA |
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| etcd/ca.crt,etcd/ca.key | etcd-ca | 与 etcd 相关的所有功能 |
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| 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) |
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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`。
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<!--
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### All certificates
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If you don't wish to copy the CA private keys to your cluster, you can generate all certificates yourself.
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Required certificates:
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-->
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### 所有的证书
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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。
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所需的证书如下列表所示：
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> 以下路径均相对于目录 `/etc/kubernetes/pki`
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| 默认 CN | 父级 CA | O (位于 Subject 中) | 类型 | 主机 (SAN) |
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|-------------------------------|---------------------------|----------------|----------------------------------------|---------------------------------------------|
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| kube-etcd | etcd-ca | | server, client | `localhost`, `127.0.0.1` |
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| kube-etcd-peer | etcd-ca | | server, client | `<hostname>`, `<Host_IP>`, `localhost`, `127.0.0.1` |
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| kube-etcd-healthcheck-client | etcd-ca | | client | |
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| kube-apiserver-etcd-client | etcd-ca | system:masters | client | |
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| kube-apiserver | kubernetes-ca | | server | `<hostname>`, `<Host_IP>`, `<advertise_IP>`, `其他 IP 或 DNS 名称 [1]` |
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| kube-apiserver-kubelet-client | kubernetes-ca | system:masters | client | |
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| front-proxy-client | kubernetes-front-proxy-ca | | client | |
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<!--
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[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`,
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`kubernetes.default.svc.cluster`, `kubernetes.default.svc.cluster.local`)
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where `kind` maps to one or more of the [x509 key usage](https://godoc.org/k8s.io/api/certificates/v1beta1#KeyUsage) types:
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-->
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[1]: 访问集群时，可能用到的其他 IP 或 DNS 名称
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（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`）。
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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)：
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<!--
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| kind | Key usage |
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|--------|---------------------------------------------------------------------------------|
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| server | digital signature, key encipherment, server auth |
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| client | digital signature, key encipherment, client auth |
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-->
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| kind | 密钥用途 |
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|--------|---------------------------------------------------------------------------------|
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| server | 数字签名、密钥加密、服务端认证 |
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| client | 数字签名、密钥加密、客户端认证 |
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<!--
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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.
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-->
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::: tip
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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。
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:::
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<!--
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For kubeadm users only:
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* The scenario where you are copying to your cluster CA certificates without private keys is referred as external CA in the kubeadm documentation.
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* 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
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are not generated in case of external etcd.
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-->
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::: tip
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如果使用 kubeadm 安装集群：
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* 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。
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* 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。
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:::
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<!--
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### Certificate paths
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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.
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-->
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### 证书路径
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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。
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| 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 |
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|------------------------------|------------------------------|-----------------------------|----------------|------------------------------|-------------------------------------------|
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| etcd-ca | etcd/ca.key | etcd/ca.crt | kube-apiserver | | --etcd-cafile |
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| kube-apiserver-etcd-client | apiserver-etcd-client.key | apiserver-etcd-client.crt | kube-apiserver | --etcd-keyfile | --etcd-certfile |
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| kubernetes-ca | ca.key | ca.crt | kube-apiserver | | --client-ca-file |
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| kubernetes-ca | ca.key | ca.crt | kube-controller-manager | --cluster-signing-key-file | --client-ca-file, --root-ca-file, --cluster-signing-cert-file |
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| kube-apiserver | apiserver.key | apiserver.crt | kube-apiserver | --tls-private-key-file | --tls-cert-file |
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| kube-apiserver-kubelet-client| apiserver-kubelet-client.key | apiserver-kubelet-client.crt| kube-apiserver | --kubelet-client-key | --kubelet-client-certificate |
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| front-proxy-ca | front-proxy-ca.key | front-proxy-ca.crt | kube-apiserver | | --requestheader-client-ca-file |
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| front-proxy-ca | front-proxy-ca.key | front-proxy-ca.crt | kube-controller-manager | | --requestheader-client-ca-file |
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| front-proxy-client | front-proxy-client.key | front-proxy-client.crt | kube-apiserver | --proxy-client-key-file | --proxy-client-cert-file |
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| etcd-ca | etcd/ca.key | etcd/ca.crt | etcd | | --trusted-ca-file, --peer-trusted-ca-file |
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| kube-etcd | etcd/server.key | etcd/server.crt | etcd | --key-file | --cert-file |
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| kube-etcd-peer | etcd/peer.key | etcd/peer.crt | etcd | --peer-key-file | --peer-cert-file |
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| etcd-ca | | etcd/ca.crt | etcdctl | | --cacert |
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| kube-etcd-healthcheck-client | etcd/healthcheck-client.key | etcd/healthcheck-client.crt | etcdctl | --key | --cert |
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<!--
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Same considerations apply for the service account key pair:
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-->
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下表罗列了 service account 的密钥对存放路径和自定义路径参数：
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| 私钥路径 | 公钥路径 | 命令 | 参数 |
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|------------------------------|-----------------------------|-------------------------|--------------------------------------|
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| sa.key | | kube-controller-manager | --service-account-private-key-file |
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| | sa.pub | kube-apiserver | --service-account-key-file |
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<!--
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## Configure certificates for user accounts
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You must manually configure these administrator account and service accounts:
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-->
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## 为用户帐户配置证书
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如下 ServiceAccount 必须手工配置：
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| 文件名 | 凭据名称 | 默认 CN | O (位于 Subject 中) |
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|-------------------------|----------------------------|--------------------------------|---------------------|
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| admin.conf | default-admin | kubernetes-admin | system:masters |
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| kubelet.conf | default-auth | system:node:`<nodeName>` （参阅注释） | system:nodes |
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| controller-manager.conf | default-controller-manager | system:kube-controller-manager | |
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| scheduler.conf | default-scheduler | system:kube-scheduler | |
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<!--
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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/).
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-->
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::: tip 注释
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`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。
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有关更多详细信息，请阅读[节点授权](https://kubernetes.io/docs/reference/access-authn-authz/node/)。
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:::
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<!--
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1. For each config, generate an x509 cert/key pair with the given CN and O.
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2. Run `kubectl` as follows for each config:
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-->
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1. 对于每个配置，请使用指定的 CN 和 O 生成 x509 证书/密钥对。
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2. 为每个配置运行下面的 `kubectl` 命令：
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```shell
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KUBECONFIG=<filename> kubectl config set-cluster default-cluster --server=https://<host ip>:6443 --certificate-authority <path-to-kubernetes-ca> --embed-certs
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KUBECONFIG=<filename> kubectl config set-credentials <credential-name> --client-key <path-to-key>.pem --client-certificate <path-to-cert>.pem --embed-certs
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KUBECONFIG=<filename> kubectl config set-context default-system --cluster default-cluster --user <credential-name>
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KUBECONFIG=<filename> kubectl config use-context default-system
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```
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<!--
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These files are used as follows:
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| filename | command | comment |
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|-------------------------|-------------------------|-----------------------------------------------------------------------|
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| admin.conf | kubectl | Configures administrator user for the cluster |
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| kubelet.conf | kubelet | One required for each node in the cluster. |
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| controller-manager.conf | kube-controller-manager | Must be added to manifest in `manifests/kube-controller-manager.yaml` |
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| scheduler.conf | kube-scheduler | Must be added to manifest in `manifests/kube-scheduler.yaml` |
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-->
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生成的文件用途如下：
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| 文件名 | 命令 | 说明 |
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|-------------------------|-------------------------|-----------------------------------------------------------------------|
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| admin.conf | kubectl | 配置集群的管理员 |
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| kubelet.conf | kubelet | 集群中的每个节点都需要一份 |
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| controller-manager.conf | kube-controller-manager | 必需添加到 `manifests/kube-controller-manager.yaml` 清单中 |
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| scheduler.conf | kube-scheduler | 必需添加到 `manifests/kube-scheduler.yaml` 清单中 |
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