默認情況下kubernetes在初始化集羣時，證書有效期年限爲1年。手動生成證書可以避免這個問題。
拉取git代碼
git clone https://github.com/fandaye/k8s-tls.git && cd k8s-tls/
2. 編輯配置文件 `apiserver.json` 文件 hosts 部分，添加對應kubernetes master 節點 主機名及IP地址，以 `,` 號間隔。如：
{
"CN": "kube-apiserver",
"hosts": [
"172.16.50.131",
"172.16.50.132",
"172.16.50.104",
"k8s01",
"k8s02",
"k8s03",
"10.96.0.1",
"kubernetes",
"kubernetes.default",
"kubernetes.default.svc",
"kubernetes.default.svc.cluster",
"kubernetes.default.svc.cluster.local"
],
"key": {
"algo": "rsa",
"size": 2048
}
}3. 執行腳本
./run.sh
4. 生成節點admin.conf，kubelet.conf，controller-manager.conf，scheduler.conf配置文件
cd /etc/kubernetes/pki
編輯 `node.sh` 文件，ip 爲當前節點ip地址，NODE 爲當前節點主機名，如：
ip="172.16.50.131" NODE="k8s01"
編輯 `kubelet.json ` 文件，CN 區域，爲對應主機名，如：
"CN": "system:node:k8s01"
執行腳本
./node.sh
完成上面步驟，在初始化kubernetes集羣，如果證書及配置文件存在，就會使用現有的
[certificates] Using the existing ca certificate and key. [certificates] Using the existing apiserver certificate and key. [certificates] Using the existing apiserver-kubelet-client certificate and key. [certificates] Using the existing sa key. [certificates] Using the existing front-proxy-ca certificate and key. [certificates] Using the existing front-proxy-client certificate and key. [certificates] Valid certificates and keys now exist in "/etc/kubernetes/pki" [kubeconfig] Using existing up-to-date KubeConfig file: "/etc/kubernetes/admin.conf" [kubeconfig] Using existing up-to-date KubeConfig file: "/etc/kubernetes/kubelet.conf" [kubeconfig] Using existing up-to-date KubeConfig file: "/etc/kubernetes/controller-manager.conf" [kubeconfig] Using existing up-to-date KubeConfig file: "/etc/kubernetes/scheduler.conf"
如果master爲多個節點，拷貝/etc/kubernetes/pki 目錄下所有文件到其他master節點，參考4步驟生成admin.conf，kubelet.conf，controller-manager.conf，scheduler.conf配置文件.
master爲多個節點 建議使用 --config 初始化集羣，但是官網提示：Caution: The config file is still considered alpha and may change in future versions.
參考：https://kubernetes.io/docs/reference/setup-tools/kubeadm/kubeadm-init/
config.yaml 文件，參考如下：
apiVersion: kubeadm.k8s.io/v1alpha1 kind: MasterConfiguration kubernetesVersion: v1.10.4 networking: podSubnet: 10.244.0.0/16 apiServerCertSANs: #master節點主機名及ip地址 - k8s01 - k8s02 - k8s03 - 172.16.50.131 - 172.16.50.132 - 172.16.50.104 - 172.16.50.227 apiServerExtraArgs: endpoint-reconciler-type: "lease" etcd: endpoints: # etcd集羣地址 - http://172.16.50.131:2379 - http://172.16.50.132:2379 - http://172.16.50.133:2379 token: "deed3a.b3542929fcbce0f0" tokenTTL: "0"