sudo mkdir -p /etc/docker
  sudo tee /etc/docker/daemon.json <<-'EOF'
  {
    "registry-mirrors": ["https://opvvjpc5.mirror.aliyuncs.com"]
  }
  EOF
  sudo systemctl daemon-reload  
  sudo systemctl restart docker 

  (1). 查看docker的版本:docker -v
  (2). 设置开机自启动:sudo systemctl enable docker
  (3). 查看镜像:sudo docker images 
  (4). 设置docker里面容器自启动:sudo docker update redis --restart=always

  sudo docker pull mysql:5.7

  # --name指定容器名字 -v目录挂载 -p指定端口映射  -e设置mysql参数 -d后台运行
  sudo docker run -p 3306:3306 --name mysql \
  -v /mydata/mysql/log:/var/log/mysql \
  -v /mydata/mysql/data:/var/lib/mysql \
  -v /mydata/mysql/conf:/etc/mysql \
  -e MYSQL_ROOT_PASSWORD=root \
  -d mysql:5.7

  docker ps
  docker exec -it mysql/容器ID /bin/bash 使用守护式进程

  # 因为有目录映射,所以我们可以直接在镜像外执行
  vi /mydata/mysql/conf/my.conf 
  [client]
  default-character-set=utf8
  [mysql]
  default-character-set=utf8
  [mysqld]
  init_connect='SET collation_connection = utf8_unicode_ci'
  init_connect='SET NAMES utf8'
  character-set-server=utf8
  collation-server=utf8_unicode_ci
  skip-character-set-client-handshake
  skip-name-resolve
  docker restart mysql