CentOS 8 实现mariadb的多实例

一、提前准备

*

centos8主机，关闭SElinux、关闭防火墙、时间同步、

二、安装mariadb

>

 yum -y install mariadb-server

三、准备三个实列的目录

 mkdir -pv /mysql/{3306,3307,3308}/{data,etc,socket,log,bin,pid}

chown -R mysql.mysql /mysql

四、生成数据库文件

mysql_install_db --datadir=/mysql/3306/data --user=mysql

mysql_install_db --datadir=/mysql/3307/data --user=mysql

mysql_install_db --datadir=/mysql/3308/data --user=mysql

五、准备配置文件

[root@centos8 ~]#vim /mysql/3306/etc/my.cnf

[mysqld]

port=3306

datadir=/mysql/3306/data

socket=/mysql/3306/socket/mysql.sock

log-error=/mysql/3306/log/mysql.log

pid-file=/mysql/3306/pid/mysql.pid

#重复上面步骤设置3307，3308

六、准备启动脚本

[root@centos8 ~]#vim /mysql/3306/bin/mysqld

#!/bin/bash

port=3306

mysql_user="root"

mysql_pwd="magedu"

cmd_path="/usr/bin"

mysql_basedir="/mysql"

mysql_sock="${mysql_basedir}/${port}/socket/mysql.sock"

function_start_mysql()

{

    if [ ! -e "$mysql_sock" ];then

     printf "Starting MySQL...\n"

     ${cmd_path}/mysqld_safe --defaults

file=${mysql_basedir}/${port}/etc/my.cnf &> /dev/null &

   else

    printf "MySQL is running...\n"

     exit

   fi

}

function_stop_mysql()

{

   if [ ! -e "$mysql_sock" ];then

      printf "MySQL is stopped...\n"

      exit

   else

      printf "Stoping MySQL...\n"

      ${cmd_path}/mysqladmin -u ${mysql_user} -p${mysql_pwd} -S ${mysql_sock}

shutdown

  fi

}

function_restart_mysql()

{

  printf "Restarting MySQL...\n"

  function_stop_mysql

   sleep 2

  function_start_mysql

}

case $1 in

start)

  function_start_mysql

;;

stop)

  function_stop_mysql

;;

restart)

  function_restart_mysql

;;

*)

  printf "Usage: ${mysql_basedir}/${port}/bin/mysqld {start|stop|restart}\n"

esac

[root@centos8 ~]#chmod +x /mysql/3306/bin/mysqld

#重复上述过程，分别建立3307，3308的启动脚本

七、启动服务

[root@centos8 ~]#/mysql/3306/bin/mysqld start

[root@centos8 ~]#/mysql/3307/bin/mysqld start

[root@centos8 ~]#/mysql/3308/bin/mysqld start

[root@centos8 ~]#ss -ntl         

#查看3306、3307、3308端口是否打开

八、登陆示例

[root@centos8 ~]#/mysql/3308/bin/mysqld start

#两种连接方法

[root@centos8 ~]#mysql -h127.0.0.1 -P3308

[root@centos8 ~]#mysql -uroot -S /mysqldb/3306/socket/mysql.sock

#确认连接的端口

MariaDB [(none)]> show variables like 'port';

+---------------+-------+

| Variable_name | Value |

+---------------+-------+

| port         | 3308 |

+---------------+-------+

1 row in set (0.001 sec)

MariaDB [(none)]>

#关闭数据库，需要手动输入root的密码

[root@centos8 ~]#/mysql/3308/bin/mysqld stop

Stoping MySQL...

Enter password:

[root@centos8 ~]#/mysql/3308/bin/mysqld start

Starting MySQL...

九、修改root密码

#加上root的口令

[root@centos8 ~]#mysqladmin -uroot -S /mysql/3306/socket/mysql.sock password

'magedu'

[root@centos8 ~]#mysqladmin -uroot -S /mysql/3307/socket/mysql.sock password

'magedu'

[root@centos8 ~]#mysqladmin -uroot -S /mysql/3308/socket/mysql.sock password

'magedu'

#或者登录mysql,执行下面也可以

Mariadb>update mysql.user set password=password(“centos”) where user=’root’;

Mariadb>flush privileges;

#重复步骤，分别修改别外两个实例3307，3308对应root口令

十、测试连接

[root@centos8 ~]#mysql -uroot -p -S /mysql/3306/socket/mysql.sock

#提示输入口令才能登录

 

十一、编写service文件，使用service进行开启、关闭mariadb服务

[root@centos8-6 ~]# vim /lib/systemd/system/mysqld3306.service

[root@centos8-6 ~]# cat /lib/systemd/system/mysqld3306.service

[Unit]

Description=MariaDB 10.3 database server

Documentation=man:mysqld(8)

Documentation=https://mariadb.com/kb/en/library/systemd/

After=network.target

 

[Install]

WantedBy=multi-user.target

 

[Service]

#Type=forking

ExecStart=/mysql/3306/bin/mysqld start

ExecStop=/mysql/3306/bin/mysqld stop

#写好文件后使用systemctl daemon-reload重新加载服务

#另两个实例分别写两个service文件

Systemctl start mysqld3306

Systemctl start mysqld3306 mysqld3307 mysqld3308

Systemctl stop mysqld3306

Systemctl enable mysqld3306