安装docker后，执行下面命令：
docker swarm init --advertise-addr 192.168.42.238
其中--advertise-addr参数是监听地址。
输出如下：
Swarm initialized: current node (yyo3t491kjc1zyql5e7gfpy4p) is now a manager.
To add a worker to this swarm, run the following command:
docker swarm join \
--token SWMTKN-1-5fh7hqkf9hd8gdyagkt1g2z9py5wcgjzbccik46euuqve9el1n-cyjainemcmsj6oz7gwmvsr45r \
192.168.42.238:2377
To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.
记录一下token，后面会会用到，之后可以使用下面命令查看集群节点：
docker node ls
在其他内网的主机的docker，可以通过下面命令加入集群
docker swarm join --token SWMTKN-1-5fh7hqkf9hd8gdyagkt1g2z9py5wcgjzbccik46euuqve9el1n-cyjainemcmsj6oz7gwmvsr45r 192.168.42.238:2377
