Detailed explanation of how to create multiple instances of MySQL 5.6 in centos7 environment

> mkdir -p /mysql-instance/3308/data
> mkdir -p /mysql-instance/3309/data

> cp /data/mysql56/support-files/my-default.cnf /mysql-instance/3308/my.cnf
> cp /data/mysql56/support-files/my-default.cnf /mysql-instance/3309/my.cnf

> vi /mysql-instance/3308/my.cnf
> vi /mysql-instance/3309/my.cnf

[client]
port = 3308
socket = /mysql-instance/3308/mysql.sock
[mysql]
no-auto-rehash
[mysqld]
user = mysql
port = 3308
socket = /mysql-instance/3308/mysql.sock
basedir = /data/mysql56
datadir = /mysql-instance/3308/data
pid-file = /mysql-instance/3308/mysql.pid
relay-log = /mysql-instance/3308/relay-bin
relay-log-info-file = /mysql-instance/3308/relay-log.info
server-id = 12
[mysqld_safe]
log-error = /mysql-instance/3308/mysql.err
pid-file = /mysql-instance/3308/mysql.pid

>vi /mysql-instance/3308/mysql
>vi /mysql-instance/3309/mysql

#!/bin/sh
port=3308
mysql_user="root"
#Please fill in your own database password mysql_pwd="123456"
cmd_path="/data/mysql56/bin"
mysql_sock="/mysql-instance/${port}/mysql.sock"
mysql_start() {
  if [ ! -e "$mysql_sock" ];then
    printf "mysql start ... \n"
    /bin/sh ${cmd_path}/mysqld_safe --defaults-file=/mysql-instance/${port}/my.cnf 2>&1 > /dev/null &
  else
    printf "mysql is running ... \n"
    exit
  fi
}
mysql_stop() {
  if [ ! -e "$mysql_sock" ];then
    printf "mysql is stopped ... \n"
    exit
  else
    printf "mysql stop ... \n"
    ${cmd_path}/mysqladmin -u ${mysql_user} -p${mysql_pwd} -S /mysql-instance/${port}/mysql.sock shutdown
  fi
}
mysql_restart() {
  printf "mysql restart ... \n"
  mysql_stop
  sleep 2
  mysql_start
}
case $1 in
  start) mysql_start ;;
  stop)mysql_stop;;
  restart)mysql_restart ;;
*)
printf "usage: /data/${port}/mysql {start|stop|restart}\n"
esac

> chown -R mysql.mysql /mysql-instance
> chmod 700 /mysql-instance/3308/mysql
> chmod 700 /mysql-instance/3309/mysql

> cd /daa/mysql56/scripts
> ./mysql_install_db --basedir=/data/mysql56 --datadir=/mysql-instance/3308/data --user=mysql
> ./mysql_install_db --basedir=/data/mysql56 --datadir=/mysql-instance/3309/data --user=mysql

> /mysql-instance/3308/mysql start
> /mysql-instance/3309/mysql start
> netstat -lntup|grep 330

> mysql -uroot -p -S /mysql-instance/3308/mysql.sock