国内环境docker pull 太慢
本文给出更换阿里云镜像的方法

Rancher

DOCKER_OPTS='
-H tcp://0.0.0.0:2376
-H unix:///var/run/docker.sock
--storage-driver overlay
--tlsverify
--tlscacert /var/lib/rancher/conf/ca.pem
--tlscert /var/lib/rancher/conf/server.pem
--tlskey /var/lib/rancher/conf/server-key.pem
--label provider=virtualbox

'

重启Rancher生效

Boot2Docker

XTRA_ARGS='
--label provider=virtualbox

'
CACERT=/var/lib/boot2docker/ca.pem
DOCKER_HOST='-H tcp://0.0.0.0:2376'
DOCKER_STORAGE=aufs
DOCKER_TLS=auto
SERVERKEY=/var/lib/boot2docker/server-key.pem
SERVERCERT=/var/lib/boot2docker/server.pem

重启boot2docker生效

centos 7

#安装docker
curl -sSL  | sh -
#设置docker registry 镜像
sudo cp -n /lib/systemd/system/docker.service /etc/systemd/system/docker.service
sudo sed -i "s|ExecStart=/usr/bin/dockerd|ExecStart=/usr/bin/dockerd  /etc/systemd/system/docker.service
#设置docker 自启动服务
systemctl enable docker.service
systemctl daemon-reload
systemctl restart  docker.service