一、实验背景
运维经常要和数据库打交道，尤其是MySQL，以前的方式是在本机装个MySQL用于本地调试，但有了docker以后就不需要再去繁琐的安装MySQL啦（虽然安装MySQL也不是很麻烦），直接在docker中启一个MySQL容器就可以了。
二、实验环境
操作系统：CentOS7.5 Minimal
IP: 192.168.1.107
三、 安装docker，拉取MySQL镜像
关闭selinux
# setenforce 0
# sed -i 's/^SELINUX=.*/SELINUX=permissive/g' /etc/selinux/config
开放相关端口
# firewall-cmd --zone=public --add-port=3306/tcp --permanent
# firewall-cmd --reload
安装docker
# yum -y install yum-utils device-mapper-persistent-data lvm2
# yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
# yum list docker-ce --showduplicates | sort -r
# yum -y install docker-ce-18.06.0.ce
# systemctl start docker
# systemctl status docker
# systemctl enable docker
# docker version
设置镜像加速
# curl -sSL https://get.daocloud.io/daotools/set_mirror.sh | sh -s http://f1361db2.m.daocloud.io
# systemctl restart docker
拉取MySQL5.7.x镜像
# docker pull mysql:5.7.20
# docker images
# docker run -it --rm mysql:5.7.20 cat /etc/issue
# docker run -it --rm mysql:5.7.20 cat /etc/passwd
四、初始化MySQL
# mkdir /opt/mysqldata
# mkdir /opt/mysqlconfig
# vim /opt/mysqlconfig/mysqld.cnf
#########################################################
# Copyright (c) 2014, 2016, Oracle and/or its affiliates. All rights reserved.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 2 of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
#
# The MySQL Server configuration file.
#
# For explanations see
# http://dev.mysql.com/doc/mysql/en/server-system-variables.html
[mysqld]
pid-file = /var/run/mysqld/mysqld.pid
socket = /var/run/mysqld/mysqld.sock
datadir = /var/lib/mysql
#log-error = /var/log/mysql/error.log
# By default we only accept connections from localhost
#bind-address = 127.0.0.1
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
#################################################################
# chown 999:999 /opt/mysqlconfig/mysqld.cnf
注意：/opt/mysqlconfig/mysqld.cnf如果属主属组为root，那么权限要求为644，如果属组属主uid为999（容器中mysql用户的uid），文件权限可以为644或者640，否则用镜像起MySQL容器，无法读取自定义的挂载配置文件！
# docker run -d \
--name mysql \
-p 3306:3306 \
-e UMASK=0600 \
-e UMASK_DIR=0700 \
-e MYSQL_HISTFILE=/dev/null \
-e MYSQL_ROOT_PASSWORD="MySQL@123" \
-v /opt/mysqldata:/var/lib/mysql \
-v /opt/mysqlconfig/mysqld.cnf:/etc/mysql/mysql.conf.d/mysqld.cnf \
mysql:5.7.20
# docker ps -a
# ll /opt/mysqldata
可以看出，生成了MySQL初始化数据，我们后续会用到相关数据，如设置的初始密码。
关于MySQL配置调优，大家可以根据自己的实际应用去编辑mysqld.cnf，本文使用的容器中默认配置。
五、删掉初始化容器，改用systemd控制服务
删掉初始化容器
# docker stop mysql
# docker rm mysql
创建MySQL的systemd Unit文件
# vim /etc/systemd/system/mysqld.service
#######################################################
[Unit]
Description=MySQL Server
After=network-online.target docker.service
Requires=docker.service
[Service]
ExecStartPre=-/usr/bin/docker rm -f mysql
ExecStart=/usr/bin/docker run \
--name mysql \
-p 192.168.1.107:3306:3306 \
-e UMASK=0600 \
-e UMASK_DIR=0700 \
-e MYSQL_HISTFILE=/dev/null \
-v /opt/mysqldata:/var/lib/mysql \
-v /opt/mysqlconfig/mysqld.cnf:/etc/mysql/mysql.conf.d/mysqld.cnf \
mysql:5.7.20
ExecStop=/usr/bin/docker stop mysql
LimitNOFILE=65535
Restart=on-failure
StartLimitBurst=3
StartLimitInterval=60s
[Install]
WantedBy=multi-user.target
########################################################
# systemctl daemon-reload
# systemctl start mysqld.service
# systemctl enable mysqld.service
# systemctl status mysqld.service
# docker ps -a
# docker logs mysql
六、参考
How to use this image Start a mysql server instance
https://docs.docker.com/samples/library/mysql
mysql/mysql-docker
https://github.com/mysql/mysql-docker
Centos下使用Docker部署MySQL
https://www.cnblogs.com/seethrough/p/9010522.html
Linux Centos7.x 安装部署Mysql5.7几种方式的操作手册
https://www.cnblogs.com/easonscx/p/10644346.html
用nexus3.x 官方镜像搭建docker私有镜像仓库
https://www.jianshu.com/p/86e573f18df3
基于docker部署MySQL的数据持久化问题
https://www.jianshu.com/p/530d00f97cbf
MySQL查看最大连接数和修改最大连接数
https://www.cnblogs.com/aaronguo/p/8412800.html
MySQL+MGR 单主模式和多主模式的集群环境
https://www.cnblogs.com/kevingrace/p/10470226.html
