解决k8s集群kubeadm init初始化镜像pull不下来的问题

新版本的Kubernetes在安装部署中，需要从k8s.grc.io仓库中拉取所需镜像文件，但由于国内网络防火墙问题导致无法正常拉取。

kubeadm init 所出现的问题：

[preflight] Some fatal errors occurred:
    [ERROR ImagePull]: failed to pull image [k8s.gcr.io/kube-apiserver-amd64:v1.11.2]: exit status 1
    [ERROR ImagePull]: failed to pull image [k8s.gcr.io/kube-controller-manager-amd64:v1.11.2]: exit status 1
    [ERROR ImagePull]: failed to pull image [k8s.gcr.io/kube-scheduler-amd64:v1.11.2]: exit status 1
    [ERROR ImagePull]: failed to pull image [k8s.gcr.io/kube-proxy-amd64:v1.11.2]: exit status 1
    [ERROR ImagePull]: failed to pull image [k8s.gcr.io/pause:3.1]: exit status 1
    [ERROR ImagePull]: failed to pull image [k8s.gcr.io/etcd-amd64:3.2.18]: exit status 1
    [ERROR ImagePull]: failed to pull image [k8s.gcr.io/coredns:1.1.3]: exit status 1

解决方法：

#!/bin/bash
K8S_VERSION=v1.13.1
ETCD_VERSION=3.2.24
DASHBOARD_VERSION=v1.8.3
FLANNEL_VERSION=v0.10.0-amd64
DNS_VERSION=1.2.0
PAUSE_VERSION=3.1
# 基本组件
docker pull mirrorgooglecontainers/kube-apiserver-amd64:$K8S_VERSION
docker pull mirrorgooglecontainers/kube-controller-manager-amd64:$K8S_VERSION
docker pull mirrorgooglecontainers/kube-scheduler-amd64:$K8S_VERSION
docker pull mirrorgooglecontainers/kube-proxy-amd64:$K8S_VERSION
docker pull mirrorgooglecontainers/etcd-amd64:$ETCD_VERSION
docker pull mirrorgooglecontainers/pause:$PAUSE_VERSION
docker pull coredns/coredns:$DNS_VERSION

# 网络组件
docker pull quay.io/coreos/flannel:$FLANNEL_VERSION

# 修改tag
docker tag mirrorgooglecontainers/kube-apiserveramd64:$K8S_VERSION k8s.gcr.io/kube-apiserver-amd64:$K8S_VERSION
docker tag mirrorgooglecontainers/kube-controller-manageramd64:$K8S_VERSION k8s.gcr.io/kube-controller-manager-amd64:$K8S_VERSION
docker tag mirrorgooglecontainers/kube-scheduleramd64:$K8S_VERSION k8s.gcr.io/kube-scheduler-amd64:$K8S_VERSION
docker tag mirrorgooglecontainers/kube-proxyamd64:$K8S_VERSION k8s.gcr.io/kube-proxy-amd64:$K8S_VERSION
docker tag mirrorgooglecontainers/etcd-amd64:$ETCD_VERSION k8s.gcr.io/etcd-amd64:$ETCD_VERSION
docker tag mirrorgooglecontainers/pause:$PAUSE_VERSION k8s.gcr.io/pause:$PAUSE_VERSION
docker tag coredns/coredns:$DNS_VERSION k8s.gcr.io/coredns:$DNS_VERSION

#删除冗余的images
docker rmi mirrorgooglecontainers/kube-apiserver-amd64:$K8S_VERSION
docker rmi mirrorgooglecontainers/kube-controller-manager-amd64:$K8S_VERSION
docker rmi mirrorgooglecontainers/kube-scheduler-amd64:$K8S_VERSION
docker rmi mirrorgooglecontainers/kube-proxy-amd64:$K8S_VERSION
docker rmi mirrorgooglecontainers/etcd-amd64:$ETCD_VERSION
docker rmi mirrorgooglecontainers/pause:$PAUSE_VERSION
docker rmi coredns/coredns:$DNS_VERSION