mysql数据库（DBMS+数据库）
系统：rock8.8
mysql：mariabd-server 10.3

前提：
关闭SElinux
关闭防火墙
时间同步

安装mariabd
yum -y install mariadb-server

准备三个实例的目录

mkdir -pv

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

生成数据文件
mysql_install_db --user=mysql --datadir=/mysql/3306/data
mysql_install_db --user=mysql --datadir=/mysql/3307/data
mysql_install_db --user=mysql --datadir=/mysql/3308/data

准备配置文件
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

sed 's/3306/3307/' /mysql/3306/etc/my.cnf > /mysql/3307/etc/my.cnf #写入其他配置文件

准备启动脚本
vim /mysql/3306/bin/mysqld

#!/bin/bash
port=3306
mysql_user="root"
mysql_pwd="root"
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}  -S ${mysql_sock}
   # ${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

sed 's/3306/3308/' /mysql/3306/bin/mysqld > /mysql/3308/bin/mysqld
sed 's/3306/3307/' /mysql/3306/bin/mysqld > /mysql/3307/bin/mysqld #复制其他实例

启动服务
/mysql/3306/bin/mysqld start 或 mysql -uroot -proot -P3306

修改root密码
mysqladmin -uroot -S /mysql/3306/socket/mysql.sock password 'root' #将启动脚本也一起修改，启用密码

如果需要开机启动
/etc/rc.d/rc.load
/mysql/3306/bin/mysqld start