一個kubeadm.config文件--定義了token，擴展了默認端口,外部ETCD集羣，自定義docker倉庫,基於ipvs的kubeproxy

這個版本是基於kubeadm.k8s.io/v1alpha3的，若是到了beta1，可能還要變更呢。

apiVersion: kubeadm.k8s.io/v1alpha3
kind: InitConfiguration
apiEndpoint:
  advertiseAddress: ${THIS_HOST}
  bindPort: ${K8S_API_PORT}
bootstrapTokens:
- groups:
  - system:bootstrappers:kubeadm:default-node-token
  token: ${K8S_JOIN_TOKEN}
  ttl: 0s
  usages:
  - signing
  - authentication
---
apiVersion: kubeadm.k8s.io/v1alpha3
kind: ClusterConfiguration
etcd:
  external:
    endpoints:
    - https://${HOST_1}:${ETCD_CLI_PORT}
    - https://${HOST_2}:${ETCD_CLI_PORT}
    - https://${HOST_3}:${ETCD_CLI_PORT}
    caFile: ${pki_dir}/etcd/ca.crt
    certFile: ${pki_dir}/apiserver-etcd-client.crt
    keyFile: ${pki_dir}/apiserver-etcd-client.key
imageRepository: ${REGISTRY}
kubernetesVersion: ${K8S_VER}
#controlPlaneEndpoint: ${K8S_DOMAIN}:${K8S_API_PORT}
apiServerExtraArgs:
  service-node-port-range: 30000-50000
networking:
  podSubnet: 10.244.0.0/16
  serviceSubnet: 10.96.0.0/12
---
apiVersion: kubeproxy.config.k8s.io/v1alpha1
kind: KubeProxyConfiguration
mode: "ipvs"