1. 背景
MySQL數據庫的集中化運維，可以通過在一台服務器上，部署運行多個MySQL服務進程，通過不同的socket監聽不同的服務端口來提供各自的服務。各個實例之間是相互獨立的，每個實例的datadir, port, socket, pid都是不同的。
2. 多實例特點
* 有效利用服務器資源，當單個服務器資源有剩余時，可以充分利用剩余的資源提供更多的服務。
* 資源互相搶占問題，當某個服務實例服務並發很高時或者開啟慢查詢時，會消耗更多的內存、CPU、磁盤IO資源，導致服務器上的其他實例提供服務的質量下降。
3. 環境 [ 關閉SeLinux ]
[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
4. 部署 [ 4個實例 ]
* 下載 MySQL 5.7 二制包 [ 推薦官方下載 ] 此下載版本大於5.7.5
[root@MySQL ~]# wget wget https://dev.mysql.com/get/Downloads/MySQL-5.7/mysql-5.7.18-linux-glibc2.5-x86_64.tar.gz
* 解壓 MySQL 5.7 二進制包到指定目錄
[root@MySQL ~]# tar zxvf mysql-5.7.18-linux-glibc2.5-x86_64.tar.gz -C /usr/local/
* 創建 MySQL 軟鏈接
[root@MySQL ~]# ln -s /usr/local/mysql-5.7.18-linux-glibc2.5-x86_64 /usr/local/mysql
* 創建 MySQL 用戶
[root@MySQL ~]# useradd -r -s /sbin/nologin mysql
* 在 MySQL 二進制包目錄中創建 mysql-files 目錄 [MySQL 數據導入/導出數據專放目錄]
[root@MySQL ~]# mkdir -v /usr/local/mysql/mysql-files
mkdir: created directory `/usr/local/mysql/mysql-files'
* 創建多實例數據目錄
[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'
* 修改 MySQL 二進制包目錄的所屬用戶與所屬組
1 [root@MySQL ~]# chown root.mysql -R /usr/local/mysql-5.7.18-linux-glibc2.5-x86_64
* 修改 MySQL 多實例數據目錄與 數據導入/導出專放目錄的所屬用戶與所屬組
[root@MySQL ~]# chown mysql.mysql -R /usr/local/mysql/mysql-files /data/mysql_data{1..4}
* 配置 MySQL 配置文件 /etc/my.cnf
[mysqld_multi]
mysqld = /usr/local/mysql/bin/mysqld
mysqladmin = /usr/local/mysql/bin/mysqladmin
log = /tmp/mysql_multi.log
[mysqld1]
# 設置數據目錄 [多實例中一定要不同]
datadir = /data/mysql_data1
# 設置sock存放文件名 [多實例中一定要不同]
socket = /tmp/mysql.sock1
# 設置監聽開放端口 [多實例中一定要不同]
port = 3306
# 設置運行用戶
user = mysql
# 關閉監控
performance_schema = off
# 設置innodb 緩存大小
innodb_buffer_pool_size = 32M
# 設置監聽IP地址
bind_address = 0.0.0.0
# 關閉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
* 初始化各個實例 [ 初始化完成后會自帶隨機密碼在輸出日志中 ]
[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
* 各實例開啟 SSL 連接
[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
* 復制多實例腳本到服務管理目錄下 [ /etc/init.d/ ]
[root@MySQL ~]# cp /usr/local/mysql/support-files/mysqld_multi.server /etc/init.d/mysqld_multi
* 添加腳本執行權限
[root@MySQL ~]# chmod +x /etc/init.d/mysqld_multi
* 添加進service服務管理
[root@MySQL ~]# chkconfig --add mysqld_multi
5. 啟動測試
* 查個多實例狀態
[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
* 啟動多實例
[root@MySQL ~]# /etc/init.d/mysqld_multi start
* 查看多實例狀態
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
* 查看實例監聽端口
[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
6. 連接測試
* 實例1
[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)
* 實例2
[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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