144 lines
10 KiB
Markdown
144 lines
10 KiB
Markdown
---
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title: PKI証明書とその要件
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content_template: templates/concept
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weight: 40
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---
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{{% capture overview %}}
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Kubernetes requires PKI certificates for authentication over TLS.
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If you install Kubernetes with [kubeadm](/docs/reference/setup-tools/kubeadm/kubeadm/), the certificates that your cluster requires are automatically generated.
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You can also generate your own certificates -- for example, to keep your private keys more secure by not storing them on the API server.
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This page explains the certificates that your cluster requires.
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## クラスタではどのように証明書が使われているのか
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Kubernetes requires PKI for the following operations:
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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][proxy]
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{{< note >}}
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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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{{< /note >}}
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etcd also implements mutual TLS to authenticate clients and peers.
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## 証明書の保存場所
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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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## 手動で証明書を設定する
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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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### 単一ルート認証局
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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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Required CAs:
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| path | Default CN | description |
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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][proxy] |
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### 全ての証明書
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If you don't wish to copy these private keys to your API servers, you can generate all certificates yourself.
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Required certificates:
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| Default CN | Parent CA | O (in Subject) | kind | hosts (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>`, `[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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[1]: `kubernetes`, `kubernetes.default`, `kubernetes.default.svc`, `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][usage] types:
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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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### 証明書のパス
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Certificates should be placed in a recommended path (as used by [kubeadm][kubeadm]). Paths should be specified using the given argument regardless of location.
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| Default CN | recommended key path | recommended cert path | command | key argument | cert argument |
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|------------------------------|------------------------------|-----------------------------|----------------|------------------------------|-------------------------------------------|
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| etcd-ca | etcd/ca.key | etcd/ca.crt | kube-apiserver | | --etcd-cafile |
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| 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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| kube-apiserver | apiserver.key | apiserver.crt | kube-apiserver | --tls-private-key-file | --tls-cert-file |
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| apiserver-kubelet-client | apiserver-kubelet-client.key | apiserver-kubelet-client.crt| kube-apiserver | | --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-client | front-proxy-client.key | front-proxy-client.crt | kube-apiserver | --proxy-client-key-file | --proxy-client-cert-file |
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| | | | | | |
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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[2] | | --cacert |
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| kube-etcd-healthcheck-client | etcd/healthcheck-client.key | etcd/healthcheck-client.crt | etcdctl[2] | --key | --cert |
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[2]: For a liveness probe, if self-hosted
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## ユーザアカウント用に証明書を設定する
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You must manually configure these administrator account and service accounts:
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| filename | credential name | Default CN | O (in Subject) |
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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>` (see note) | system:nodes |
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| controller-manager.conf | default-controller-manager | system:kube-controller-manager | |
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| scheduler.conf | default-manager | system:kube-scheduler | |
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{{< note >}}
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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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{{< /note >}}
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1. For each config, generate an x509 cert/key pair with the given CN and O.
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1. Run `kubectl` as follows for each config:
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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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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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[usage]: https://godoc.org/k8s.io/api/certificates/v1beta1#KeyUsage
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[kubeadm]: /docs/reference/setup-tools/kubeadm/kubeadm/
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[proxy]: /docs/tasks/access-kubernetes-api/configure-aggregation-layer/
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{{% /capture %}}
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