CleverCode最近在研究mysql的多实例，发现有两种方式：
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。
推荐使用多个配置文件方式。这种实际应用中好，耦合性不强，配置方便，特别是主从复制的时候。
上一篇《mysql多实例（多个配置文件方式）》：http://blog.csdn.net/clevercode/article/details/47610619。介绍了多个配置文件方式。本篇将介绍mysqld_multi方式。
1 环境介绍：
1）简介
mysql 版本：mysql-5.5.27
cmake：cmake-2.8.8
操作系统：CentOS6.5
mysql实例数：3个
实例占用端口分别为：3306、3307、3308
2）本次安装所有的软件资源包下载地址
http://download.csdn.net/detail/clevercode/8662323
2 配置防火墙
1) 在防火墙配置文件中添加3306，3307,3308（允许3306，3307,3308端口通过防火墙）
# vi /etc/sysconfig/iptables #编辑防火墙配置文件
-A INPUT -m state --state NEW -m tcp -p tcp --dport 3306 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 3307 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 3308 -j ACCEPT
2）重启防火墙
# /etc/init.d/iptables restart #最后重启防火墙使配置生效
3 安装cmake
解压
# cd /usr/local/src/mysql
# tar zxvf cmake-2.8.8.tar.gz
# cd cmake-2.8.8
配置
# ./configure
编译
# make
安装
# make install
查看版本
# cmake -version
4 安装Mysql
1) 创建用户
# groupadd mysql #添加mysql组
# useradd -g mysql mysql -s /bin/false #创建用户mysql并加入到mysql组，不允许mysql用户直接登录系统
2) 解压
# cd /usr/local/src/mysql
# tar zxvf mysql-5.5.27.tar.gz
# cd mysql-5.5.27
4) 配置
# cmake . -DCMAKE_INSTALL_PREFIX=/usr/local/mysql
PS: cmake的时候，参数可以不用那么多，只要一个-DCMAKE_INSTALL_PREFIX=/usr/local/mysql就行了，我们可以在 my.cnf里面配置。[mysqld]中的内容，看看你copy后的my.cnf有没有这些设置，有就不用了在设置了。
5）编译
# make
6)安装
# make install
5 初始化数据库
# mkdir -p /data0/dbdata/mysql/3306
# mkdir -p /data0/dbdata/mysql/3307
# mkdir -p /data0/dbdata/mysql/3308
# chown -R mysql:mysql /data0/dbdata/mysql/3306
# chown -R mysql:mysql /data0/dbdata/mysql/3307
# chown -R mysql:mysql /data0/dbdata/mysql/3308
# /usr/local/mysql/scripts/mysql_install_db --basedir=/usr/local/mysql --datadir=/data0/dbdata/mysql/3306 --user=mysql
# /usr/local/mysql/scripts/mysql_install_db --basedir=/usr/local/mysql --datadir=/data0/dbdata/mysql/3307 --user=mysql
# /usr/local/mysql/scripts/mysql_install_db --basedir=/usr/local/mysql --datadir=/data0/dbdata/mysql/3308 --user=mysql
6 修改配置文件（只用/etc/my.cnf文件）
# cp /usr/local/mysql/support-files/my-huge.cnf /etc/my.cnf
# vi /etc/my.cnf
[mysqld_multi]
mysqld = /usr/local/mysql/bin/mysqld_safe
mysqladmin = /usr/local/mysql/bin/mysqladmin
#用于登陆和关闭此服务
user = root
password = CleverCode123
[mysqld3306]
#数据目录
datadir = /data0/dbdata/mysql/3306
#连接
port = 3306
socket = /tmp/mysql3306.sock
#binlog
log-bin=/data0/dbdata/mysql/3306/mysql-bin
pid-file = /data0/dbdata/mysql/3306/mysql_3306.pid
[mysqld3307]
datadir = /data0/dbdata/mysql/3307
port = 3307
socket = /tmp/mysql3307.sock
log-bin=/data0/dbdata/mysql/3307/mysql-bin
pid-file = /data0/dbdata/mysql/3307/mysql_3307.pid
[mysqld3308]
datadir = /data0/dbdata/mysql/3308
port = 3308
socket = /tmp/mysql3308.sock
log-bin=/data0/dbdata/mysql/3308/mysql-bin
pid-file = /data0/dbdata/mysql/3308/mysql_3308.pid
7 启动3306、3307、3308的mysql
# /usr/local/mysql/bin/mysqld_multi start 3306
# /usr/local/mysql/bin/mysqld_multi start 3307
# /usr/local/mysql/bin/mysqld_multi start 3308
8 查看端口是否监听，如果出现3306,3307,3308则启动正常
# netstat -anp | grep 3308
tcp 0 0 0.0.0.0:3308 0.0.0.0:* LISTEN 2348/mysqld
unix 2 [ ACC ] STREAM LISTENING 10780 2348/mysqld /tmp/mysql3308.sock
9 初始化密码并且授权远程登录，mysqladmin用户名和密码需要和/ect/my.cnf中保持一致，否则stop不了服务。
# /usr/local/mysql/bin/mysqladmin -u root password "CleverCode123" -S /tmp/mysql3306.sock
# /usr/local/mysql/bin/mysql -uroot -pCleverCode123 -S /tmp/mysql3306.sock
mysql> grant all privileges on *.* to 'root'@'%' identified by 'pwd3306' with grant option;
mysql> flush privileges;
# /usr/local/mysql/bin/mysqladmin -u root password "CleverCode123" -S /tmp/mysql3307.sock
# /usr/local/mysql/bin/mysql -uroot -pCleverCode123 -S /tmp/mysql3307.sock
mysql> grant all privileges on *.* to 'root'@'%' identified by 'pwd3307' with grant option;
mysql> flush privileges;
# /usr/local/mysql/bin/mysqladmin -u root password "CleverCode123" -S /tmp/mysql3308.sock
# /usr/local/mysql/bin/mysql -uroot -pCleverCode123 -S /tmp/mysql3308.sock
mysql> grant all privileges on *.* to 'root'@'%' identified by 'pwd3308' with grant option;
mysql> flush privileges;
10 停止（必须先初始化密码）。可以使用netstat -anp | grep 3308查看监听进程是否还存在
# /usr/local/mysql/bin/mysqld_multi stop 3306
# /usr/local/mysql/bin/mysqld_multi stop 3307
# /usr/local/mysql/bin/mysqld_multi stop 3308
11 报告。显示进程的状态
# /usr/local/mysql/bin/mysqld_multi report 3306
# /usr/local/mysql/bin/mysqld_multi report 3307
# /usr/local/mysql/bin/mysqld_multi report 3308
