kubeadm 是kubernetes 的集群安装工具，能够快速安装kubernetes 集群。kubeadm init 命令默认使用的docker镜像仓库为k8s.gcr.io，国内无法直接访问，需要中转一下才可以使用。

首先查看需要哪些镜像

kubeadm config images list

[root@master ~]# kubeadm config images list
I1215 20:40:10.170825    2583 version.go:94] could not fetch a Kubernetes version from the internet: unable to get URL "https://dl.k8s.io/release/stable-1.txt": Get https://storage.googleapis.com/kubernetes-release/release/stable-1.txt: net/http: request canceled (Client.Timeout exceeded while awaiting headers)
I1215 20:40:10.170992    2583 version.go:95] falling back to the local client version: v1.13.1
k8s.gcr.io/kube-apiserver:v1.13.1
k8s.gcr.io/kube-controller-manager:v1.13.1
k8s.gcr.io/kube-scheduler:v1.13.1
k8s.gcr.io/kube-proxy:v1.13.1
k8s.gcr.io/pause:3.1
k8s.gcr.io/etcd:3.2.24
k8s.gcr.io/coredns:1.2.6

通过 docker.io/mirrorgooglecontainers中转一下https://hub.docker.com/u/mirrorgooglecontainers

批量下载及转换标签

kubeadm config images list |sed -e 's/^/docker pull /g' -e 's#k8s.gcr.io#docker.io/mirrorgooglecontainers#g' |sh -x  下载需要的镜像

docker images |grep mirrorgooglecontainers |awk '{print "docker tag ",$1":"$2,$1":"$2}' |sed -e 's#mirrorgooglecontainers#k8s.gcr.io#2' |sh -x  重命名镜像

docker images |grep mirrorgooglecontainers |awk '{print "docker rmi ", $1":"$2}' |sh -x 删除mirrorgooglecontainers镜像

coredns没包含在docker.io/mirrorgooglecontainers中，需要手工从coredns官方镜像转换下。

docker pull coredns/coredns:1.2.6
docker tag coredns/coredns:1.2.6 k8s.gcr.io/coredns:1.2.6
docker rmi coredns/coredns:1.2.6

查看镜像列表

[root@master ~]# docker images
REPOSITORY                           TAG                 IMAGE ID            CREATED             SIZE
k8s.gcr.io/kube-proxy                v1.13.1             fdb321fd30a0        2 days ago          80.2MB
k8s.gcr.io/kube-apiserver            v1.13.1             40a63db91ef8        2 days ago          181MB
k8s.gcr.io/kube-controller-manager   v1.13.1             26e6f1db2a52        2 days ago          146MB
k8s.gcr.io/kube-scheduler            v1.13.1             ab81d7360408        2 days ago          79.6MB
k8s.gcr.io/coredns                   1.2.6               f59dcacceff4        5 weeks ago         40MB
k8s.gcr.io/etcd                      3.2.24              3cab8e1b9802        2 months ago        220MB
k8s.gcr.io/pause                     3.1                 da86e6ba6ca1        11 months ago       742kB

另外一种方法是使用kubeadm配置文件，通过在配置文件中指定docker仓库地址，便于内网快速部署。

生成配置文件

kubeadm config print-defaults --api-objects ClusterConfiguration >kubeadm.conf

将配置文件中的

imageRepository: k8s.gcr.io

改为你自己的私有docker仓库，比如

imageRepository: docker.io/mirrorgooglecontainers

kubeadm生成的配置文件目前不够完善，需要修改kubernetes版本

kubernetesVersion: v1.13.1

改为

kubernetesVersion: v1.13.1

然后运行命令

kubeadm config images list --config kubeadm.conf
kubeadm config images pull --config kubeadm.conf
kubeadm init --config kubeadm.conf

更多kubeadm配置文件参数详见

kubeadm config print-defaults