修改 Kubernetes apiserver 启动参数

本文描述了修改 Kubernetes apiserver 启动参数的步骤。

如果您使用 kubeadm 安装 Kubernetes 集群，Kubernetes apiserver 通过 static pod 启动，其 yaml 文件的位置在 /etc/kubernetes/manifests/kube-apiserver.yaml 这个路径下，如下所示：（其中第 14 行到第 39 行，都是 kube-apiserver 的启动参数）

apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    component: kube-apiserver
    tier: control-plane
  name: kube-apiserver
  namespace: kube-system
spec:
  containers:
  - command:
    - kube-apiserver
    - --advertise-address=172.17.184.171
    - --allow-privileged=true
    - --authorization-mode=Node,RBAC
    - --client-ca-file=/etc/kubernetes/pki/ca.crt
    - --enable-admission-plugins=NodeRestriction
    - --enable-bootstrap-token-auth=true
    - --etcd-cafile=/etc/kubernetes/pki/etcd/ca.crt
    - --etcd-certfile=/etc/kubernetes/pki/apiserver-etcd-client.crt
    - --etcd-keyfile=/etc/kubernetes/pki/apiserver-etcd-client.key
    - --etcd-servers=https://127.0.0.1:2379
    - --insecure-port=0
    - --kubelet-client-certificate=/etc/kubernetes/pki/apiserver-kubelet-client.crt
    - --kubelet-client-key=/etc/kubernetes/pki/apiserver-kubelet-client.key
    - --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname
    - --proxy-client-cert-file=/etc/kubernetes/pki/front-proxy-client.crt
    - --proxy-client-key-file=/etc/kubernetes/pki/front-proxy-client.key
    - --requestheader-allowed-names=front-proxy-client
    - --requestheader-client-ca-file=/etc/kubernetes/pki/front-proxy-ca.crt
    - --requestheader-extra-headers-prefix=X-Remote-Extra-
    - --requestheader-group-headers=X-Remote-Group
    - --requestheader-username-headers=X-Remote-User
    - --secure-port=6443
    - --service-account-key-file=/etc/kubernetes/pki/sa.pub
    - --service-cluster-ip-range=10.96.0.0/16
    - --tls-cert-file=/etc/kubernetes/pki/apiserver.crt
    - --tls-private-key-file=/etc/kubernetes/pki/apiserver.key
    image: registry.cn-hangzhou.aliyuncs.com/google_containers/kube-apiserver:v1.17.1
    imagePullPolicy: IfNotPresent
    livenessProbe:
      failureThreshold: 8
      httpGet:
        host: 172.17.184.171
        path: /healthz
        port: 6443
        scheme: HTTPS
      initialDelaySeconds: 15
      timeoutSeconds: 15
    name: kube-apiserver
...

假设您要向 Kubernetes apiserver 追加如下 oidc 参数时，将这些参数追加到该 yaml 文件的 command 字段中即可，

    - --oidc-issuer-url=https://dex.demo.kuboard.cn:32001
    - --oidc-client-id=kuboard-dex-client
    - --oidc-username-claim=preferred_username
    - --oidc-username-prefix=-
    - --oidc-groups-claim=groups
    - --oidc-groups-prefix=

修改后的文件如下所示：

apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    component: kube-apiserver
    tier: control-plane
  name: kube-apiserver
  namespace: kube-system
spec:
  containers:
  - command:
    - kube-apiserver
    - --advertise-address=172.17.184.171
    - --allow-privileged=true
    - --authorization-mode=Node,RBAC
    - --client-ca-file=/etc/kubernetes/pki/ca.crt
    - --enable-admission-plugins=NodeRestriction
    - --enable-bootstrap-token-auth=true
    - --etcd-cafile=/etc/kubernetes/pki/etcd/ca.crt
    - --etcd-certfile=/etc/kubernetes/pki/apiserver-etcd-client.crt
    - --etcd-keyfile=/etc/kubernetes/pki/apiserver-etcd-client.key
    - --etcd-servers=https://127.0.0.1:2379
    - --insecure-port=0
    - --kubelet-client-certificate=/etc/kubernetes/pki/apiserver-kubelet-client.crt
    - --kubelet-client-key=/etc/kubernetes/pki/apiserver-kubelet-client.key
    - --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname
    - --proxy-client-cert-file=/etc/kubernetes/pki/front-proxy-client.crt
    - --proxy-client-key-file=/etc/kubernetes/pki/front-proxy-client.key
    - --requestheader-allowed-names=front-proxy-client
    - --requestheader-client-ca-file=/etc/kubernetes/pki/front-proxy-ca.crt
    - --requestheader-extra-headers-prefix=X-Remote-Extra-
    - --requestheader-group-headers=X-Remote-Group
    - --requestheader-username-headers=X-Remote-User
    - --secure-port=6443
    - --service-account-key-file=/etc/kubernetes/pki/sa.pub
    - --service-cluster-ip-range=10.96.0.0/16
    - --tls-cert-file=/etc/kubernetes/pki/apiserver.crt
    - --tls-private-key-file=/etc/kubernetes/pki/apiserver.key
    - --oidc-issuer-url=https://dex.demo.kuboard.cn:32001
    - --oidc-client-id=kuboard-dex-client
    - --oidc-username-claim=preferred_username
    - --oidc-username-prefix=-
    - --oidc-groups-claim=groups
    - --oidc-groups-prefix=
    image: registry.cn-hangzhou.aliyuncs.com/google_containers/kube-apiserver:v1.17.1
    imagePullPolicy: IfNotPresent
    livenessProbe:
      failureThreshold: 8
      httpGet:
        host: 172.17.184.171
        path: /healthz
        port: 6443
        scheme: HTTPS
      initialDelaySeconds: 15
      timeoutSeconds: 15
    name: kube-apiserver
...

生效

Static Pod 的配置文件被修改后，立即生效。

• Kubelet 会监听该文件的变化，当您修改了 /etc/kubernetes/manifests/kube-apiserver.yaml 文件之后，kubelet 将自动终止原有的 kube-apiserver-{nodename} 的 Pod，并自动创建一个使用了新配置参数的 Pod 作为替代。
• 如果您有多个 Kubernetes Master 节点，您需要在每一个 Master 节点上都修改该文件，并使各节点上的参数保持一致。