CentOS7安装MySql多实例
安装之前的环境
在安装多实例之前首先先在虚拟机中的服务器里边先安装好一个MySql，本人的MySql版本为mysql-5.7.9-linux-glibc2.5-x86_64，端口为3306
开始安装一个新实例
1.在local目录下，创建一个data3文件夹，
cd /usr/local
mkdir data3
请忽略我的data1和data2
到etc修改my.cnf文件，如果没有就创建，
vi my.cnf
将下面的文本粘贴上去
[root@localhost etc]# vi my.cnf
[mysqld_multi]
mysqld = /usr/local/mysql/bin/mysqld_safe
mysqladmin =/usr/local/mysql/bin/mysqladmin
log =/usr/local/mysql/mysqld_multi.log
[mysqld1]
socket = /tmp/mysql1.sock
port = 3307
pid-file = /usr/local/data1/mysql.pid
datadir = /usr/local/data1
server-id = 1
[mysqld2]
socket = /tmp/mysql2.sock
port = 3308
pid-file = /usr/local/data2/mysql.pid
datadir = /usr/local/data2
server-id = 2
[mysqld3]
socket = /tmp/mysql3.sock
port = 3309
pid-file = /usr/local/data3/mysql.pid
datadir = /usr/local/data3
server-id = 3
我之前安装过两个实例一个端口是mysqld1，一个端口是mysqld2，这次我要装是mysql3，可根据自己的实际情况做调整。
再回到刚才的文件
cd /usr/local
执行安装命令
mysqld --initialize --user=mysql --datadir=/usr/local/data3
安装成功会有一个初始密码，一定要记下来
执行命令
cp /usr/local/mysql/support-files/mysqld_multi.server /etc/init.d/mysqld_multid
配置开机启动
chkconfig mysqld_multid on
查看状态
mysqld_multi report
结果
Reporting MySQL servers
MySQL server from group: mysqld1 is running
MySQL server from group: mysqld2 is running
MySQL server from group: mysqld3 is not running
启动多实例
mysqld_multi start
再次查看实例是否启动,，如果启动不来就重启机器再试试
[root@localhost local]# mysqld_multi report
Reporting MySQL servers
MySQL server from group: mysqld1 is running
MySQL server from group: mysqld2 is running
MySQL server from group: mysqld3 is running
修改密码，允许远程连接，再输入密码
mysql -u root -S /tmp/mysql.sock3 -p -P3309 -h127.0.0.1
这里有bug，就是输入密码会提示错误
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)
尝试重启mysql服务器依然无效
service mysql restart
然后把data3的目录删除后重新安装，还是登录不了，之后重启服务器再试就可以了。如果没有遇到这个情况可以跳过重装和重启步骤。
重启之后登录成功
[root@localhost local]# mysql -u root -S /tmp/mysql.sock3 -p -P3309 -h127.0.0.1
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.7.9
Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
修改密码
set password = 'root1234%';
分配root权限，并刷新权限
GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY 'root1234%';
flush privileges;
此时已经成功了一大半了，再设置一下防火墙，让其他机器能连上。
1.先看一下端口
firewall-cmd --zone=public --list-ports
结果
3306/tcp 3307/tcp
2.开放一个端口
firewall-cmd --zone=public --add-port=3309/tcp --permanent
3.将防火墙重启
firewall-cmd --reload
试试物理机是否能连上虚拟机的mysql实例
