基于之前的mysql5.7单实例安装
修改/etc/my.cnf文件如下(这里配置4个实例，可自行修改数目)
#
# 多实例配置文件，可以mysqld_multi --example 查看例子
#
[root@MyServer /]> cat /etc/my.cnf
#[client] # 这个标签如果配置了用户和密码，
# 并且[mysqld_multi]下没有配置用户名密码，
# 则mysqld_multi stop时, 会使用这个密码
# 如果没有精确的匹配，则匹配[client]标签
#user = root
#password = 123
#-------------
[mysqld_multi]
mysqld = /usr/local/mysql/bin/mysqld_safe
mysqladmin = /usr/local/mysql/bin/mysqladmin
user = multi_admin
pass = 123 # 官方文档中写的password，但是存在bug，需要改成pass(v5.7.9)
# 写成password，start时正常，stop时，报如下错误
# Access denied for user 'multi_admin'@'localhost' (using password: YES)
log = /var/log/mysqld_multi.log
[mysqld1]
server-id = 11
socket = /tmp/mysql.sock1
port = 3306
bind_address = 0.0.0.0
datadir = /data1
user = mysql
performance_schema = off
innodb_buffer_pool_size = 32M
skip_name_resolve = 1
log_error = error.log
pid-file = /data1/mysql.pid1
[mysqld2]
server-id = 12
socket = /tmp/mysql.sock2
port = 3307
bind_address = 0.0.0.0
datadir = /data2
user = mysql
performance_schema = off
innodb_buffer_pool_size = 32M
skip_name_resolve = 1
log_error = error.log
pid-file = /data2/mysql.pid2
[mysqld3]
server-id = 13
socket = /tmp/mysql.sock3
port = 3308
bind_address = 0.0.0.0
datadir = /data3
user = mysql
performance_schema = off
innodb_buffer_pool_size = 32M
skip_name_resolve = 1
log_error = error.log
pid-file = /data3/mysql.pid3
[mysqld4]
server-id = 14
socket = /tmp/mysql.sock4
port = 3309
bind_address = 0.0.0.0
datadir = /data4
user = mysql
performance_schema = off
innodb_buffer_pool_size = 32M
skip_name_resolve = 1
log_error = error.log
pid-file = /data4/mysql.pid4准备好数据目录，并初始化安装
[root@MyServer ~]> mkdir /data1
[root@MyServer ~]> mkdir /data2
[root@MyServer ~]> mkdir /data3
[root@MyServer ~]> mkdir /data4
[root@MyServer ~]> chown mysql.mysql /data{1..4}
[root@MyServer ~]> mysqld --initialize --user=mysql --datadir=/data1
#
# 一些日志输出，并提示临时密码，下同
#
[root@MyServer ~]> mysqld --initialize --user=mysql --datadir=/data2
[root@MyServer ~]> mysqld --initialize --user=mysql --datadir=/data3
[root@MyServer ~]> mysqld --initialize --user=mysql --datadir=/data4
# 安装后，需要检查error.log 确保没有错误出现
[root@MyServer ~]> cp /usr/local/mysql/support-files/mysqld_multi.server /etc/init.d/mysqld_multid
# 拷贝启动脚本，方便自启
[root@MyServer ~]> chkconfig mysqld_multid on
[root@MyServer ~]> mysqld_multi start
[root@MyServer ~]> 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
MySQL server from group: mysqld4 is running
[root@MyServer ~]> netstat -tunlp | grep mysql
[root@MyServer ~]> netstat -tunlp | grep mysql
tcp 0 0 :::3307 :::* LISTEN 6221/mysqld
tcp 0 0 :::3308 :::* LISTEN 6232/mysqld
tcp 0 0 :::3309 :::* LISTEN 6238/mysqld
tcp 0 0 :::3306 :::* LISTEN 6201/mysqld
[root@MyServer ~]> mysql -u root -S /tmp/mysql.sock1 -p -P3306
#
# 使用-S /tmp/mysql.sock1 进行登录，并输入临时密码后，修改密码，下同
#
[root@MyServer ~]> mysql -u root -S /tmp/mysql.sock2 -p -P3307
[root@MyServer ~]> mysql -u root -S /tmp/mysql.sock3 -p -P3308
[root@MyServer ~]> mysql -u root -S /tmp/mysql.sock4 -p -P3309
#输入临时密码,开始修改密码
#MySQL版本5.7.6版本以前用户可以使用如下命令：
mysql> SET PASSWORD = PASSWORD('123456');
#MySQL版本5.7.6版本开始的用户可以使用如下命令：
mysql> ALTER USER USER() IDENTIFIED BY '123456';
--
-- mysql1
--
mysql> show variables like "port";
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| port | 3306 |
+---------------+-------+
1 row in set (0.00 sec)
mysql> show variables like "socket";
+---------------+------------------+
| Variable_name | Value |
+---------------+------------------+
| socket | /tmp/mysql.sock1 |
+---------------+------------------+
1 row in set (0.01 sec)
mysql> show variables like "datadir";
+---------------+---------+
| Variable_name | Value |
+---------------+---------+
| datadir | /data1/ |
+---------------+---------+
1 row in set (0.00 sec)
--
-- mysql2, mysql3, mysql4 类似。可以看到与my.cnf中对应的port和socket
--
## 关闭数据库(mysqld_multi stop 好像不起作用)
pkill -9 mysql 如果使用 mysqld_multi report 发现有配置的数据库实例没有running ，查看配置datadir中错误日志，如果没有错误日志的话，可以删除datadir中的文件,检查my.cnf中是否有错误，重新执行初始化