预习：
使用到的docker命令：
docker images 显示本地有的镜像
docker pull +镜像名称 从docker hub上面拉取镜像
docker run
--name 定义容器的名称
-d 让docker容器在后台运行到
-a 查看已经创建的容器
-s 查看启动的容器
docker start docker_name 启动名称为docker_name的容器
docker stop docker_name 关闭名称为docker_name的容器
docker rm docker_name 删除名称为docker_name的容器
docker rmi docker_name 删除名称为docker_name的镜像
docker rename old_name new_name 给容器重命名
操作：
[root@localhost ~]# docker pull mysql 拉取镜像
[root@localhost ~]# docker images|grep mysql 查看镜像
docker.io/mysql latest 6a834f03bd02 2 weeks ago 484 MB
[root@localhost ~]# docker run -e MYSQL_ROOT_PASSWORD=123456 --name mysql -it mysql 启动一个容器
[root@localhost ~]# docker ps -s 查看正在运行的容器
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES SIZE
dc1c39266b16 mysql "docker-entrypoint..." 3 days ago Up 2 hours 3306/tcp, 33060/tcp mysql 119 B (virtual 484 MB)
连接MySQL数据库
[root@localhost ~]# docker exec -it dc1c39266b16 bash
root@dc1c39266b16:/# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 9
Server version: 8.0.12 MySQL Community Server - GPL
Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>
已经连接上数据库了。