mysql多实例介绍及配置

mysql多实例介绍及配置

1、mysql多实例介绍

1.1 什么是mysql多实例

mysql多实例就是在一台机器上开启多个不同的服务端口（如：3306,3307），运行多个MySQL服务进程，通过不同的socket监听不同的服务端口来提供各自的服务:；

1.2 mysql多实例的特点有以下几点

1：有效利用服务器资源，当单个服务器资源有剩余时，可以充分利用剩余的资源提供更多的服务。

2：节约服务器资源

3：资源互相抢占问题，当某个服务实例服务并发很高时或者开启慢查询时，会消耗更多的内存、CPU、磁盘IO资源，导致服务器上的其他实例提供服务的质量下降；

1.3 部署mysql多实例的两种方式

第一种是使用多个配置文件启动不同的进程来实现多实例，这种方式的优势逻辑简单，配置简单，缺点是管理起来不太方便；

第二种是通过官方自带的mysqld_multi使用单独的配置文件来实现多实例，这种方式定制每个实例的配置不太方面，优点是管理起来很方便，集中管理；

1.4 同一开发环境下安装两个数据库，必须处理以下问题

配置文件安装路径不能相同

数据库目录不能相同

启动脚本不能同名

端口不能相同

socket文件的生成路径不能相同

2、mysqld_multi配置mysql多实例

在进行此操作前已经编译安装好了mysql，安装位置在/application/mysql/下

2.1 初始化数据目录

mkdir /usr/local/var -p

/application/mysql/scripts/mysql_install_db --basedir=/application/mysql/ --datadir=/usr/local/var/mysql1 --user=mysql

/application/mysql/scripts/mysql_install_db --basedir=/application/mysql/ --datadir=/usr/local/var/mysql2 --user=mysql

/application/mysql/scripts/mysql_install_db --basedir=/application/mysql/ --datadir=/usr/local/var/mysql3 --user=mysql

/application/mysql/scripts/mysql_install_db --basedir=/application/mysql/ --datadir=/usr/local/var/mysql4 --user=mysql

修改授权

chown -R mysql.mysql /usr/local/var/mysql*

2.2 配置多实例启动脚本

cp /application/mysql/support-files/mysqld_multi.server /etc/init.d/

#修改basedir和bindir为安装路径

basedir=/application/mysql

bindir=/application/mysql/bin

2.3 配置多实例数据库配置文件

在/etc/目录下创建创建文件/etc/mysqld_multi.cnf，内容如下

[mysqld_multi]

mysqld = /application/mysql/bin/mysqld_safe

mysqladmin = /application/mysql/bin/mysqladmin

#user = mysql

#password = my_password

[mysqld1]

socket = /usr/local/var/mysql1/mysql1.sock

port = 3306

pid-file = /usr/local/var/mysql1/mysql1.pid

datadir = /usr/local/var/mysql1

#language = /usr/local/mysql/share/mysql/english

user = mysql

[mysqld2]

socket = /usr/local/var/mysql2/mysql2.sock

port = 3307

pid-file = /usr/local/var/mysql2/mysql2.pid

datadir = /usr/local/var/mysql2

#language = /usr/local/mysql/share/mysql/english

user = mysql

[mysqld3]

socket = /usr/local/var/mysql3/mysql3.sock

port = 3308

pid-file = /usr/local/var/mysql3/mysql3.pid

datadir = /usr/local/var/mysql3

#language = /usr/local/mysql/share/mysql/english

user = mysql

[mysqld4]

socket = /usr/local/var/mysql4/mysql4.sock

port = 3309

pid-file = /usr/local/var/mysql4/mysql4.pid

datadir = /usr/local/var/mysql4

#language = /usr/local/mysql/share/mysql/english

user = mysql

2.4 启动多实例数据库

mysqld_multi --defaults-extra-file=/etc/mysqld_multi.cnf start

#启动或停止具体某一个实例可在start、stop后面加上具体数据1,2,3等

mysqld_multi进行多实例管理

启动全部实例：/usr/local/mysql/bin/mysqld_multi --defaults-extra-file=/etc/mysqld_multi.cnf start

查看全部实例状态：/usr/local/mysql/bin/mysqld_multi report

启动单个实例：/usr/local/mysql/bin/mysqld_multi --defaults-extra-file=/etc/mysqld_multi.cnf start 3306

停止单个实例：/usr/local/mysql/bin/mysqld_multi --defaults-extra-file=/etc/mysqld_multi.cnf stop 3306

查看单个实例状态：/usr/local/mysql/bin/mysqld_multi --defaults-extra-file=/etc/mysqld_multi.cnf report 3306

检查

[root@db02 ~]# netstat -lntup

Active Internet connections (only servers)

Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name

tcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN 5016/mysqld

tcp 0 0 0.0.0.0:3307 0.0.0.0:* LISTEN 5026/mysqld

tcp 0 0 0.0.0.0:3308 0.0.0.0:* LISTEN 5036/mysqld

tcp 0 0 0.0.0.0:3309 0.0.0.0:* LISTEN 5042/mysqld

tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1317/sshd

tcp 0 0 :::22 :::* LISTEN 1317/sshd

2.5 登录相应数据库

#进入端口为3306的数据库

mysql -uroot -p -h127.0.0.1 -P3306 ####密码为空

或者

mysql -S /usr/local/var/mysql1/mysql1.sock

3、多配置文件实现MySQL多实例

在进行此操作前已经编译安装好了mysql，安装位置在/application/mysql/下

3.1 创建目录和配置文件

mkdir -p /data/{3306,3307}/data

vim /data/3306/my.cnf

[client]

port = 3306

socket = /data/3306/mysql.sock

[mysql]

no-auto-rehash

[mysqld]

user = mysql

port = 3306

socket = /data/3306/mysql.sock

basedir = /application/mysql

datadir = /data/3306/data

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

log-bin = /data/3306/mysql-bin

relay-log = /data/3306/relay-bin

relay-log-info-file = /data/3306/relay-log.info

server-id = 1

[mysqld_safe]

log-error=/data/3306/mysql_3306.err

pid-file=/data/3306/mysqld.pid

3.2 创建启动脚本

vim /data/3306/mysql

#!/bin/sh

#init

port=3306

CmdPath="/application/mysql/bin"

mysql_sock="/data/${port}/mysql.sock"

#startup function

function_start_mysql()

{

if [ ! -e "$mysql_sock" ];then

printf "Starting MySQL...\n"

/bin/sh ${CmdPath}/mysqld_safe --defaults-file=/data/${port}/my.cnf 2>&1 > /dev/null &

else

printf "MySQL is running...\n"

exit

fi

}

#stop function

function_stop_mysql()

{

if [ ! -e "$mysql_sock" ];then

printf "MySQL is stopped...\n"

exit

else

printf "Stoping MySQL...\n"

${CmdPath}/mysqladmin -u ${mysql_user} -p${mysql_pwd} -S /data/${port}/mysql.sock shutdown

fi

}

#restart function

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: /data/${port}/mysql {start|stop|restart}\n"

esac

3.4 增加3307实例

sed 's#3306#3307#g;s#server-id = 1#server-id = 3#g' /data/3306/my.cnf >/data/3307/my.cnf

sed 's#3306#3307#g' /data/3306/mysql >/data/3307/mysql

3.5 修改权限

chown -R mysql.mysql /data

chmod +x /data/{3306,3307}/mysql

3.6 初始化

/application/mysql/scripts/mysql_install_db --user=mysql --basedir=/application/mysql --datadir=/data/3306/data

/application/mysql/scripts/mysql_install_db --user=mysql --basedir=/application/mysql --datadir=/data/3307/data

3.7 启动

/data/3306/mysql start

/data/3307/mysql start

启动的时候报错

[root@db01 ~]# 180707 16:30:54 mysqld_safe error: log-error set to '/data/3306/mysql_3306.err', however file don't exists. Create writable for user 'mysql'.

手动创建文件并授权，再次启动成功

touch /data/3306/mysql_3306.err

chown mysql:mysql /data/3306/mysql_3306.err

检查

[root@db01 ~]# netstat -lntup|grep mysql

tcp6 0 0 :::3306 :::* LISTEN 2023/mysqld

tcp6 0 0 :::3307 :::* LISTEN 2505/mysqld

3.8 初始化密码登录

mysqladmin -uroot -S /data/3306/mysql.sock password '123456'

mysqladmin -uroot -S /data/3307/mysql.sock password '123456'

参考来源：

https://www.cnblogs.com/xuchenliang/p/6843990.html

https://blog.csdn.net/clevercode/article/details/47610619

https://blog.csdn.net/clevercode/article/details/47659457