rancher with external database

version: '2'
services:
  rancher-server:
    image: 'rancher/server:stable'
    container_name: rancher-server
    restart: always
    volumes_from:
        - rancher-db
    ports:
        - "8080:8080"
    depends_on:
        - rancher-db
    environment:
        - CATTLE_DB_CATTLE_MYSQL_HOST=rancher-db
        - CATTLE_DB_CATTLE_MYSQL_PORT=3306
        - CATTLE_DB_CATTLE_MYSQL_NAME=rancher
        - CATTLE_DB_CATTLE_USERNAME=rancher
        - CATTLE_DB_CATTLE_PASSWORD=yourdbpassword
  rancher-db:
    image: mysql
    container_name: rancher-db
    restart: always
    volumes_from:
        - rancher-db-data
    ports:
        - "3306:3306"
    environment:
        - MYSQL_ROOT_PASSWORD=yourrootpasswd
        - MYSQL_DATABASE=rancher
        - MYSQL_USER=rancher
        - MYSQL_PASSWORD=yourdbpassword
    command: "--character-set-server=utf8 --collation-server=utf8_general_ci"
  rancher-db-data:
    container_name : rancher-db-data
    image: gliderlabs/alpine
    restart: always
    volumes:
        - ./rancher_data:/var/lib/mysql
    command: /bin/sh