内网服务器，无法下载docker镜像，这时需要用其他机器下载后，拷贝过去使用，方法如下：
1、下载所需image：

[root@cloud key]# docker pull mirrorgooglecontainers/kube-apiserver-amd64:v1.15.3
v1.15.3: Pulling from mirrorgooglecontainers/kube-apiserver-amd64
6cf6a0b0da0d: Pull complete 
b329b37f08d3: Pull complete 
Digest: sha256:12746ced388109e683af1c29c1c3657e0a1538030f40c0e17292f024af2bf765
Status: Downloaded newer image for mirrorgooglecontainers/kube-apiserver-amd64:v1.15.3
[root@cloud key]# docker images |grep kube
mirrorgooglecontainers/kube-apiserver-amd64    v1.15.3             5eb2d3fc7a44        7 weeks ago         206.8 MB

2、保存镜像为文件

[root@cloud key]# docker save -o kube.tar mirrorgooglecontainers/kube-apiserver-amd64
[root@cloud key]# ls |grep kube.tar
kube.tar

3、将kube.tar拷贝至目标内网服务器中
4、通过文件载入镜像

[root@master ~]# docker load < kube.tar 
fe9a8b4f1dcc: Loading layer [==================================================>]  43.87MB/43.87MB
9b49e894f11a: Loading layer [==================================================>]  164.5MB/164.5MB
Loaded image: mirrorgooglecontainers/kube-apiserver-amd64:v1.15.3
[root@master ~]# docker images
REPOSITORY                                    TAG                 IMAGE ID            CREATED             SIZE
mirrorgooglecontainers/kube-apiserver-amd64   v1.15.3             5eb2d3fc7a44        7 weeks ago         207MB