systemd 服务管理与 MySQL 多版本部署

1.整理 systemctl 数据库 Service 文件

方案一：标准生产守护进程配置

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[Unit]
Description=MySQL Server
After=network.target

[Service]
User=mysql
Group=mysql
ExecStart=/usr/local/mysql/bin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
ExecReload=/bin/kill -HUP $MAINPID
PIDFile=/var/run/mysqld/mysqld.pid
PrivateTmp=true
RuntimeDirectory=mysqld

[Install]
WantedBy=multi-user.target

方案二：带配置文件与文件句柄限制配置

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[Unit]
Description=MySQL Server
After=network.target

[Service]
User=mysql
Group=mysql
ExecStart=/usr/local/mysql/bin/mysqld --defaults-file=/etc/my.cnf
RuntimeDirectory=mysqld
LimitNOFILE=65536
Restart=on-failure

[Install]
WantedBy=multi-user.target

修改完成后

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[root@master local]#systemctl daemon-reload
[root@master local]#systemctl restart mysqld.service
[root@master local]#systemctl enable  mysqld.service

2.多版本 MySQL（5.6 / 5.7）安装与升级准备

步骤一：下载软件归档包

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# MySQL 5.7.40 二进制包
[root@master local]#wget https://downloads.mysql.com/archives/get/p/23/file/mysql-5.7.40-linux-glibc2.12-x86_64.tar.gz

# MySQL 5.6.48 二进制包
[root@master local]#wget https://downloads.mysql.com/archives/get/p/23/file/mysql-5.6.48-linux-glibc2.12-x86_64.tar.gz

步骤二：解压安装与创建软链接

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# 安装 5.7 版本
[root@master local]#tar xf mysql-5.7.40-linux-glibc2.12-x86_64.tar.gz
[root@master local]#ln -s mysql-5.7.40-linux-glibc2.12-x86_64 mysql57
# 注意：多版本共存调试期间，暂不配置全局环境变量，避免命令路径冲突

# 安装 5.6 版本
[root@master local]#tar xf mysql-5.6.48-linux-glibc2.12-x86_64.tar.gz
[root@master local]#ln -s mysql-5.6.48-linux-glibc2.12-x86_64 mysql56
# 注意：暂不配置全局环境变量

步骤三：编写多实例专属配置文件

• MySQL 5.7（3357 实例）配置：

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  [root@master local]#vim /etc/my3357.cnf [mysql] socket=/tmp/mysql3357.sock [mysqld] user=mysql basedir=/usr/local/mysql57 datadir=/data/3357/data socket=/tmp/mysql3357.sock port=3357 pid-file=/run/mysqld3357/mysqld.pid [root@master local]#vim /usr/lib/systemd/system/mysqld3357.service [Unit] Description=MySQL 5.7 Server (3357) After=network.target [Service] User=mysql Group=mysql ExecStart=/usr/local/mysql57/bin/mysqld --defaults-file=/etc/my3357.cnf RuntimeDirectory=mysqld3357 LimitNOFILE=65536 Restart=on-failure [Install] WantedBy=multi-user.target

• MySQL 5.6（3356 实例）配置：

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  [root@master local]#vim /etc/my3356.cnf [mysql] socket=/tmp/mysql3356.sock [mysqld] user=mysql basedir=/usr/local/mysql56 datadir=/data/3356/data socket=/tmp/mysql3356.sock port=3356 pid-file=/run/mysqld3356/mysqld.pid [root@master local]#vim /usr/lib/systemd/system/mysqld3356.service [Unit] Description=MySQL 5.6 Server (3356) After=network.target [Service] User=mysql Group=mysql ExecStart=/usr/local/mysql56/bin/mysqld --defaults-file=/etc/my3356.cnf RuntimeDirectory=mysqld3356 LimitNOFILE=65536 Restart=on-failure [Install] WantedBy=multi-user.target

步骤四：初始化数据库软件

• MySQL 5.6 初始化（数据目录 3356）：

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  [root@master local]#mkdir -p /data/3356/data [root@master local]#chown -R mysql.mysql /data/3356/data [root@master ~]#/usr/local/mysql56/scripts/mysql_install_db --defaults-file=/etc/my3356.cnf --user=mysql --basedir=/usr/local/mysql56 --datadir=/data/3356/data FATAL ERROR: please install the following Perl modules before executing /usr/local/mysql56/scripts/mysql_install_db: Data::Dumper # 缺少Perl模块 [root@master local]#yum install -y perl-Data-Dumper [root@master local]#/usr/local/mysql56/scripts/mysql_install_db --user=mysql --datadir=/data/3356/data --basedir=/usr/local/mysql56 # 观察输出信息中是否包含两个 OK，并确认退出状态码： [root@master local]#echo $? 0

• MySQL 5.7 初始化（数据目录 3357）：

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  [root@master local]#mkdir -p /data/3357/data [root@master local]#chown -R mysql.mysql /data/3357/data [root@master ~]#/usr/local/mysql57/bin/mysqld --defaults-file=/etc/my3357.cnf --initialize-insecure --user=mysql --basedir=/usr/local/mysql57 --datadir=/data/3357/data [root@master local]#echo $? 0

步骤五：运行启动数据库服务

• 启动/停止 MySQL 5.7 服务：

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  # 第一种启动方式 [root@master local]#cp /usr/local/mysql57/support-files/mysql.server /etc/init.d/mysqld57 [root@master local]#chmod +x /etc/init.d/mysqld57 [root@master local]#/etc/init.d/mysqld57 start [root@master local]#/etc/init.d/mysqld57 stop # 第二种启动方式 [root@master local]#systemctl daemon-reload [root@master local]#systemctl start mysqld3357.service [root@master local]#systemctl enable mysqld3357.service Created symlink from /etc/systemd/system/multi-user.target.wants/mysqld3357.service to /usr/lib/systemd/system/mysqld3357.service.

• 启动/停止 MySQL 5.6 服务：

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  # 第一种启动方式 [root@master local]#cp /usr/local/mysql56/support-files/mysql.server /etc/init.d/mysqld56 [root@master local]#chmod +x /etc/init.d/mysqld56 [root@master local]#/etc/init.d/mysqld56 start [root@master local]#/etc/init.d/mysqld56 stop # 第二种启动方式 [root@master local]#systemctl daemon-reload [root@master local]#systemctl start mysqld3356.service [root@master local]#systemctl enable mysqld3356.service Created symlink from /etc/systemd/system/multi-user.target.wants/mysqld3356.service to /usr/lib/systemd/system/mysqld3356.service.

三个服务状态验证（全都running）

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[root@master local]#for svc in mysqld mysqld3356 mysqld3357; do
>   a=$(systemctl show -p ActiveState "$svc" | cut -d= -f2)
>   s=$(systemctl show -p SubState   "$svc" | cut -d= -f2)
>   echo "$svc: $a ($s)"
> done
mysqld: active (running)
mysqld3356: active (running)
mysqld3357: active (running)