docker 创建mysql服务

version: '3'
 
services:
 
  db:
    image: mysql:5.7.23
    restart: always
    container_name: "mysql_5_7"
    environment:
      MYSQL_ROOT_PASSWORD: 123456 
    ports:
      - "3306:3306"
    volumes: 
      - ./data:/var/lib/mysql