Docker compose selenium hub + nodes

docker-compose.yml

version: '2'
services:
  hub:
    image: selenium/hub
    ports:
      - 4444:4444
    networks:
      - front-tier
      - back-tier

  node_firefox:
    image: selenium/node-firefox
    environment:
        HUB_PORT_4444_TCP_ADDR: hub
        HUB_PORT_4444_TCP_PORT: 4444
    links:
      - hub
    networks:
      - back-tier

  node_chrome:
    image: selenium/node-chrome
    environment:
        HUB_PORT_4444_TCP_ADDR: hub
        HUB_PORT_4444_TCP_PORT: 4444
    links:
      - hub
    volumes:
      - /dev/shm:/dev/shm
    networks:
      - back-tier

networks:
  front-tier:
    driver: bridge
  back-tier:
    driver: bridge

selenium.sh

#!/bin/bash
### BEGIN INIT INFO
# Provides: selenium
# Required-Start:    $local_fs $remote_fs $syslog
# Required-Stop:     $local_fs $remote_fs $syslog
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: Docker selenium pack
# Description:       selenium start|stop|restart|status|logs
### END INIT INFO

name=`basename $0`
pid_file="/var/run/$name.pid"
stdout_log="/var/log/$name.log"
stderr_log="/var/log/$name.err"
workdir="/usr/local/src/selenium-docker"
ccount=20

case "$1" in
    start)
    cd $workdir
    docker-compose up -d
    docker-compose scale node_firefox=$ccount
    docker-compose scale node_chrome=$ccount
    ;;
    stop)
    cd $workdir
    docker-compose down
    ;;
    status)
    cd $workdir
    docker-compose ps
    ;;
    logs)
    cd $workdir
    docker-compose logs
    ;;
    restart)
    $0 stop
    $0 start
    ;;
    *)
    echo "Usage: $0 {start|stop|restart|status|logs}"
    exit 1
    ;;
esac

exit 0