在A机器 服务端xx.xx.xx.xx 上
# locate docker.service
/usr/lib/systemd/system/docker.service
增加 -H tcp://0.0.0.0
ExecStart=/usr/bin/dockerd -H tcp://0.0.0.0
systemctl daemon-reload
systemctl restart docker.service
# netstat -anlp|grep docker
tcp6 0 0 :::2375 :::* LISTEN 13327/dockerd
从其他机器客户端：
# docker -H xx.xx.xx.xx info
Containers: 1
Running: 0
Paused: 0
Stopped: 1
Images: 1
Server Version: 17.10.0-ce
Storage Driver: devicemapper
Pool Name: docker-8:5-393391-pool