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。
* 网上多实例一般通过实例版本相同实现，此次以不同版本来实现多实例部署(5.5、5.6、5.7)。
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 ]
[root@MySQL ~]# cat /etc/redhat-release
CentOS release 6.9 (Final)
[root@MySQL ~]# uname -r
2.6.32-504.el6.x86_64
[root@MySQL ~]# getenforce
Disabled4. MySQL 二进制包准备
* 下载官方5.5二进制安装包
[root@MySQL ~]# wget https://dev.mysql.com/get/Downloads/MySQL-5.5/mysql-5.5.57-linux-glibc2.12-x86_64.tar.gz* 下载官方5.6二进制安装包
[root@MySQL ~]# wget https://dev.mysql.com/get/Downloads/MySQL-5.6/mysql-5.6.37-linux-glibc2.12-x86_64.tar.gz* 下载官方5.7二进制安装包
[root@MySQL ~]# wget https://dev.mysql.com/get/Downloads/MySQL-5.7/mysql-5.7.19-linux-glibc2.12-x86_64.tar5. mysql 版本初始化并统一修改密码
* 创建 MySQL 用户
[root@MySQL ~]# useradd -r -s /sbin/nologin mysql* 创建MySQL数据目录
[root@MySQL ~]# mkdir -vp /data/mysql_data_{5..7}
mkdir: created directory `/data'
mkdir: created directory `/data/mysql_data_5'
mkdir: created directory `/data/mysql_data_6'
mkdir: created directory `/data/mysql_data_7'* 修改MySQL 数据目录所属用户与所属组
[root@MySQL ~]# chown mysql.mysql -R /data/mysql_data_** 解压MySQL 各版本至 /usr/local 目录
[root@MySQL ~]# tar zxf mysql-5.5.57-linux-glibc2.12-x86_64.tar.gz -C /usr/local/
[root@MySQL ~]# tar zxf mysql-5.6.37-linux-glibc2.12-x86_64.tar.gz -C /usr/local/
[root@MySQL ~]# tar xf mysql-5.7.19-linux-glibc2.12-x86_64.tar -C /usr/local/* MySQL 5.5 初始化
[root@MySQL ~]# chown mysql.mysql -R /usr/local/mysql-5.5.57-linux-glibc2.12-x86_64
[root@MySQL ~]# /usr/local/mysql-5.5.57-linux-glibc2.12-x86_64/scripts/mysql_install_db --user=mysql --datadir=/data/mysql_data_5 --basedir=/usr/local/mysql-5.5.57-linux-glibc2.12-x86_64* MySQL 5.5 修改密码
[root@MySQL ~]# /usr/local/mysql-5.5.57-linux-glibc2.12-x86_64/bin/mysqld_safe --datadir=/data/mysql_data_5 &
[root@MySQL ~]# /usr/local/mysql-5.5.57-linux-glibc2.12-x86_64/bin/mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.5.57 MySQL Community Server (GPL)
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 = password('123');
Query OK, 0 rows affected (0.00 sec)
mysql> quit
Bye
[root@MySQL ~]# killall mysqld* MySQL 5.6 初始化
[root@MySQL ~]# chown mysql.mysql -R /usr/local/mysql-5.6.37-linux-glibc2.12-x86_64
[root@MySQL ~]# /usr/local/mysql-5.6.37-linux-glibc2.12-x86_64/scripts/mysql_install_db --user=mysql --datadir=/data/mysql_data_6 --basedir=/usr/local/mysql-5.6.37-linux-glibc2.12-x86_64* MySQL 5.6修改密码
[root@MySQL ~]# /usr/local/mysql-5.6.37-linux-glibc2.12-x86_64/bin/mysqld_safe --datadir=/data/mysql_data_6 &
[root@MySQL ~]# /usr/local/mysql-5.6.37-linux-glibc2.12-x86_64/bin/mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.6.37 MySQL Community Server (GPL)
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 = password('123');
Query OK, 0 rows affected (0.00 sec)
mysql> quit
Bye
[root@MySQL ~]# killall mysqld* MySQL 5.7 初始化 [ 注意初始化提示的随机密码 ]
[root@MySQL ~]# mkdir /usr/local/mysql-5.7.19-linux-glibc2.12-x86_64/mysql-files
[root@MySQL ~]# chown root.mysql -R /usr/local/mysql-5.7.19-linux-glibc2.12-x86_64
[root@MySQL ~]# chown mysql.mysql -R /data/mysql_data_7 /usr/local/mysql-5.7.19-linux-glibc2.12-x86_64/mysql-files
[root@MySQL ~]# /usr/local/mysql-5.7.19-linux-glibc2.12-x86_64/bin/mysqld --initialize --user=mysql --datadir=/data/mysql_data_7 --basedir=/usr/local/mysql-5.7.19-linux-glibc2.12-x86_64* MySQL 5.7修改密码
[root@MySQL ~]# /usr/local/mysql-5.7.19-linux-glibc2.12-x86_64/bin/mysqld_safe --datadir=/data/mysql_data_7 &
[root@MySQL ~]# /usr/local/mysql-5.7.19-linux-glibc2.12-x86_64/bin/mysql -p'INoGk(hoj9>/'
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 4
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 = '123';
Query OK, 0 rows affected (0.00 sec)
mysql> quit
Bye
[root@MySQL ~]# killall mysqld6. 多版本部署
* 编辑/etc/my.cnf
[client]
# 设置登陆用户
user = root
# 设置登陆用户密码
password = 123
[mysqld]
# mysql 运行用户
user = mysql
# 设置 mysql 监听 IP 地址
bind_address = 0.0.0.0
# 关闭 DNS 反解析
skip-name-resolve = 0
# 关闭监听
performance_schema = off
# 设置buffer pool 大小
innodb_buffer_pool_size = 32M
# 设置错误日志文件名
log_error = error.log
[mysqld_multi]
# 设置multi 日志
log = /tmp/mysql_multi.log
[mysqld5]
# 设置实例所在目录
basedir = /usr/local/mysql-5.5.57-linux-glibc2.12-x86_64
# 设置mysql 运行程序所在路径
mysqld = /usr/local/mysql-5.5.57-linux-glibc2.12-x86_64/bin/mysqld
# 设置mysql 管理运行程序所在路径
mysqladmin = /usr/local/mysql-5.5.57-linux-glibc2.12-x86_64/bin/mysqladmin
# 设置实例数据目录 -- 多实例中一定要不同
datadir = /data/mysql_data_5
# 设置socket 文件路径 -- 多实例中一定要不同
socket = /tmp/mysql.sock5
# 设置实例监听端口 -- 多实例中一定要不同
port = 3305
[mysqld6]
basedir = /usr/local/mysql-5.6.37-linux-glibc2.12-x86_64
mysqld = /usr/local/mysql-5.6.37-linux-glibc2.12-x86_64/bin/mysqld
mysqladmin = /usr/local/mysql-5.6.37-linux-glibc2.12-x86_64/bin/mysqladmin
datadir = /data/mysql_data_6
socket = /tmp/mysql.sock6
port = 3306
[mysqld7]
basedir = /usr/local/mysql-5.7.19-linux-glibc2.12-x86_64
datadir = /data/mysql_data_7
socket = /tmp/mysql.sock7
port = 3307* 从随意版本二进制包中support-files目录下复制mysqld_multi.server启动脚本至 /etc/init.d/
[root@MySQL ~]# cp /usr/local/mysql-5.7.19-linux-glibc2.12-x86_64/support-files/mysqld_multi.server /etc/init.d/mysqld_multi
[root@MySQL ~]# chmod +x /etc/init.d/mysqld_multi* 随意版本创始软链接，并设置环境变量
[root@MySQL ~]# ln -s /usr/local/mysql-5.7.19-linux-glibc2.12-x86_64 /usr/local/mysql
[root@MySQL ~]# export PATH=/usr/local/mysql/bin:$PATH7. 测试
* 查看多实例状态
[root@MySQL ~]# /etc/init.d/mysqld_multi report
Reporting MySQL servers
MySQL server from group: mysqld5 is not running
MySQL server from group: mysqld6 is not running
MySQL server from group: mysqld7 is not running* 启动多实例 [ 需等候几秒 ]
[root@MySQL ~]# /etc/init.d/mysqld_multi start
[root@MySQL ~]# /etc/init.d/mysqld_multi report
Reporting MySQL servers
MySQL server from group: mysqld5 is running
MySQL server from group: mysqld6 is running
MySQL server from group: mysqld7 is running
[root@MySQL ~]# netstat -lntp | grep mysqld
tcp 0 0 0.0.0.0:3305 0.0.0.0:* LISTEN 43750/mysqld
tcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN 43753/mysqld
tcp 0 0 0.0.0.0:3307 0.0.0.0:* LISTEN 43756/mysqld* 分别连接实例
[root@MySQL ~]# mysql -S /tmp/mysql.sock5
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.7.18 MySQL Community Server (GPL)
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> quit
Bye
[root@MySQL ~]# mysql -S /tmp/mysql.sock6
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.7.18 MySQL Community Server (GPL)
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> quit
Bye
[root@MySQL ~]# mysql -S /tmp/mysql.sock7
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.7.18 MySQL Community Server (GPL)
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> quit
Bye* 停止多实例
[root@MySQL ~]# /etc/init.d/mysqld_multi stop
[root@MySQL ~]# /etc/init.d/mysqld_multi report
Reporting MySQL servers
MySQL server from group: mysqld5 is not running
MySQL server from group: mysqld6 is not running
MySQL server from group: mysqld7 is not running8. 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。
