How to setup simple Docker Swarm Clustering
1. Create 3 docker machines
docker-machine create -d virtualbox --engine-registry-mirror http://8ff28fe8.m.daocloud.io vm1
docker-machine create -d virtualbox --engine-registry-mirror http://8ff28fe8.m.daocloud.io vm2
docker-machine create -d virtualbox --engine-registry-mirror http://8ff28fe8.m.daocloud.io vm3
2. Enter vm1 and config it as manager
docker machine-ssh vm1
docker swarm init --advertise-addr 192.168.99.101
