text: if [[ "$(uname -s )" == "Linux" ]]; then
    export VIRTUALBOX_SHARE_FOLDER="$PWD:$PWD"
  fi
  
  for i in 1 2 3 4; do
      docker-machine create -d virtualbox swarm-$i
  done
  
  eval $(docker-machine env swarm-1)
  
  docker swarm init --advertise-addr $(docker-machine ip swarm-1)
  
  TOKEN=$(docker swarm join-token -q manager)
  
  for i in 2 3; do
      eval $(docker-machine env swarm-$i)
  
      docker swarm join --token $TOKEN --advertise-addr $(docker-machine ip swarm-$i) $(docker-machine ip swarm-1):2377
  done
  
  TOKEN=$(docker swarm join-token -q worker)
  
  eval $(docker-machine env swarm-4)
  
  docker swarm join --token $TOKEN --advertise-addr $(docker-machine ip swarm-4) $(docker-machine ip swarm-1):2377
  
  eval $(docker-machine env swarm-1)
  
  docker node ls