1. 背景
MySQL数据库的集中化运维，可以通过在一台服务器上，部署运行多个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。各个实例之间是相互独立的，每个实例的datadir, port, socket, pid都是不同的。
2. 多实例特点
* 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。
* 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。
3. 环境 [ 关闭SeLinux ]
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[root@MySQL ~]
# cat /etc/redhat-release
CentOS release 6.9 (Final)
[root@MySQL ~]
# uname -r
2.6.32-696.3.2.el6.x86_64
[root@MySQL ~]
# getenforce
Disabled
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4. 部署 [ 4个实例 ]
* 下载 MySQL 5.7 二制包 [ 推荐官方下载 ] 此下载版本大于5.7.5
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[root@MySQL ~]
# wget wget https://dev.mysql.com/get/Downloads/MySQL-5.7/mysql-5.7.18-linux-glibc2.5-x86_64.tar.gz
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* 解压 MySQL 5.7 二进制包到指定目录
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[root@MySQL ~]
# tar zxvf mysql-5.7.18-linux-glibc2.5-x86_64.tar.gz -C /usr/local/
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* 创建 MySQL 软链接
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[root@MySQL ~]
# ln -s /usr/local/mysql-5.7.18-linux-glibc2.5-x86_64 /usr/local/mysql
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* 创建 MySQL 用户
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[root@MySQL ~]
# useradd -r -s /sbin/nologin mysql
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* 在 MySQL 二进制包目录中创建 mysql-files 目录 [MySQL 数据导入/导出数据专放目录]
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[root@MySQL ~]
# mkdir -v /usr/local/mysql/mysql-files
mkdir
: created directory `
/usr/local/mysql/mysql-files
'
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* 创建多实例数据目录
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[root@MySQL ~]
# mkdir -vp /data/mysql_data{1..4}
mkdir
: created directory `
/data
'
mkdir
: created directory `
/data/mysql_data1
'
mkdir
: created directory `
/data/mysql_data2
'
mkdir
: created directory `
/data/mysql_data3
'
mkdir
: created directory `
/data/mysql_data4
'
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* 修改 MySQL 二进制包目录的所属用户与所属组
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[root@MySQL ~]
# chown root.mysql -R /usr/local/mysql-5.7.18-linux-glibc2.5-x86_64
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* 修改 MySQL 多实例数据目录与 数据导入/导出专放目录的所属用户与所属组
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[root@MySQL ~]
# chown mysql.mysql -R /usr/local/mysql/mysql-files /data/mysql_data{1..4}
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* 配置 MySQL 配置文件 /etc/my.cnf
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[mysqld_multi]
mysqld =
/usr/local/mysql/bin/mysqld
mysqladmin =
/usr/local/mysql/bin/mysqladmin
log =
/tmp/mysql_multi
.log
[mysqld1]
# 设置数据目录 [多实例中一定要不同]
datadir =
/data/mysql_data1
# 设置sock存放文件名 [多实例中一定要不同]
socket =
/tmp/mysql
.sock1
# 设置监听开放端口 [多实例中一定要不同]
port = 3306
# 设置运行用户
user = mysql
# 关闭监控
performance_schema = off
# 设置innodb 缓存大小
innodb_buffer_pool_size = 32M
# 设置监听IP地址
bind_address = 0.0.0.0
# 关闭DNS 反向解析
skip-name-resolve = 0
[mysqld2]
datadir =
/data/mysql_data2
socket =
/tmp/mysql
.sock2
port = 3307
user = mysql
performance_schema = off
innodb_buffer_pool_size = 32M
bind_address = 0.0.0.0
skip-name-resolve = 0
[mysqld3]
datadir =
/data/mysql_data3
socket =
/tmp/mysql
.sock3
port = 3308
user = mysql
performance_schema = off
innodb_buffer_pool_size = 32M
bind_address = 0.0.0.0
skip-name-resolve = 0
[mysqld4]
datadir =
/data/mysql_data4
socket =
/tmp/mysql
.sock4
port = 3309
user = mysql
performance_schema = off
innodb_buffer_pool_size = 32M
bind_address = 0.0.0.0
skip-name-resolve = 0
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* 初始化各个实例 [ 初始化完成后会自带随机密码在输出日志中 ]
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[root@MySQL ~]
# /usr/local/mysql/bin/mysqld --initialize --user=mysql --basedir=/usr/local/mysql --datadir=/data/mysql_data1
[root@MySQL ~]
# /usr/local/mysql/bin/mysqld --initialize --user=mysql --basedir=/usr/local/mysql --datadir=/data/mysql_data2
[root@MySQL ~]
# /usr/local/mysql/bin/mysqld --initialize --user=mysql --basedir=/usr/local/mysql --datadir=/data/mysql_data3
[root@MySQL ~]
# /usr/local/mysql/bin/mysqld --initialize --user=mysql --basedir=/usr/local/mysql --datadir=/data/mysql_data4
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* 各实例开启 SSL 连接
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[root@MySQL ~]
# /usr/local/mysql/bin/mysql_ssl_rsa_setup --user=mysql --basedir=/usr/local/mysql --datadir=/data/mysql_data1
[root@MySQL ~]
# /usr/local/mysql/bin/mysql_ssl_rsa_setup --user=mysql --basedir=/usr/local/mysql --datadir=/data/mysql_data2
[root@MySQL ~]
# /usr/local/mysql/bin/mysql_ssl_rsa_setup --user=mysql --basedir=/usr/local/mysql --datadir=/data/mysql_data3
[root@MySQL ~]
# /usr/local/mysql/bin/mysql_ssl_rsa_setup --user=mysql --basedir=/usr/local/mysql --datadir=/data/mysql_data4
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* 复制多实例脚本到服务管理目录下 [ /etc/init.d/ ]
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[root@MySQL ~]
# cp /usr/local/mysql/support-files/mysqld_multi.server /etc/init.d/mysqld_multi
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* 添加脚本执行权限
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[root@MySQL ~]
# chmod +x /etc/init.d/mysqld_multi
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* 添加进service服务管理
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[root@MySQL ~]
# chkconfig --add mysqld_multi
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5. 启动测试
* 查个多实例状态
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[root@MySQL ~]
# /etc/init.d/mysqld_multi report
Reporting MySQL servers
MySQL server from group: mysqld1 is not running
MySQL server from group: mysqld2 is not running
MySQL server from group: mysqld3 is not running
MySQL server from group: mysqld4 is not running
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* 启动多实例
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[root@MySQL ~]
# /etc/init.d/mysqld_multi start
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* 查看多实例状态
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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
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* 查看实例监听端口
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[root@MySQL ~]
# netstat -lntp | grep mysqld
tcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN 2673
/mysqld
tcp 0 0 0.0.0.0:3307 0.0.0.0:* LISTEN 2676
/mysqld
tcp 0 0 0.0.0.0:3308 0.0.0.0:* LISTEN 2679
/mysqld
tcp 0 0 0.0.0.0:3309 0.0.0.0:* LISTEN 2682
/mysqld
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6. 连接测试
* 实例1
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[root@MySQL ~]
# /usr/local/mysql/bin/mysql -S /tmp/mysql.sock1 -p'z+Ilo*>s:3kw'
mysql: [Warning] Using a password on the
command
line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection
id
is 6
Server version: 5.7.18
Copyright (c) 2000, 2017, 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.
mysql>
set
password =
'123456'
;
Query OK, 0 rows affected (0.00 sec)
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* 实例2
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[root@MySQL ~]
# /usr/local/mysql/bin/mysql -S /tmp/mysql.sock2 -p'b*AHUrTgu1rl'
mysql: [Warning] Using a password on the
command
line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection
id
is 7
Server version: 5.7.18
Copyright (c) 2000, 2017, 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.
mysql>
set
password =
'123456'
;
Query OK, 0 rows affected (0.00 sec)
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7. 总结
以需求驱动技术，技术本身没有优略之分，只有业务之分。
本文转自asd1123509133 51CTO博客，原文链接：http://blog.51cto.com/lisea/1941788，如需转载请自行联系原作者
