上次在一台机器上装了两个mysql，似乎比较繁琐，被上面否决了，这次换成配个多实例的。其实之前配过，没配成功，不过资料找多了，自然就理解大概的原理了。
一、环境：
操作系统：ubuntu 10.10
mysql版本：mysql 5.1.61
二、配置步骤
综合了下面这两份资料：
http://www.cnblogs.com/andhm/archive/2012/08/01/2618028.html
http://blog.sina.com.cn/s/blog_5f3f20890100xi4p.html
1.修改配置文件：/etc/apparmor.d/usr.sbin.mysqld
（否则安装不了其它的mysql实例，会出现类似：100304 22:34:18 [Warning] Can't create test file /var/lib/mysql1/PB.lower-test的错误）
默认权限路径如下（以空行分隔的是其它mysql实例的安装位置，主要是添加并修改/var所在的那些行）：
/etc/mysql/*.pem r,
/etc/mysql/conf.d/ r,
/etc/mysql/conf.d/* r,
/etc/mysql/my.cnf r,
/usr/sbin/mysqld mr,
/usr/share/mysql/** r,
/var/log/mysql.log rw,
/var/log/mysql.err rw,
/var/lib/mysql/ r,
/var/lib/mysql/** rwk,
/var/log/mysql/ r,
/var/log/mysql/* rw,
/var/run/mysqld/mysqld.pid w,
/var/run/mysqld/mysqld.sock w,
/var/log/mysql1.log rw,
/var/log/mysql1.err rw,
/var/lib/mysql1/ r,
/var/lib/mysql1/** rwk,
/var/log/mysql1/ r,
/var/log/mysql1/* rw,
/var/run/mysqld/mysqld1.pid w,
/var/run/mysqld/mysqld1.sock w,
/var/log/mysql2.log rw,
/var/log/mysql2.err rw,
/var/lib/mysql2/ r,
/var/lib/mysql2/** rwk,
/var/log/mysql2/ r,
/var/log/mysql2/* rw,
/var/run/mysqld/mysqld2.pid w,
/var/run/mysqld/mysqld2.sock w,
2.重启apparmor：/etc/init.d/apparmor restart
3.安装新的mysql实例(分别安装到/var/lib/mysql1和/var/lib/mysql2下)：
mysql_install_db --datadir=/var/lib/mysql1 --user=mysql
mysql_install_db --datadir=/var/lib/mysql2 --user=mysql
4.配置多个实例：编辑/et/mysql/my.cnf，添加如下配置(pie-file、socket、datadir、log的位置要和之前配的位置一样）
[mysqld_mulit]
mysqld = /usr/bin/mysqld_safe
mysqladmin = /usr/bin/mysqladmin
user = root
password = 11111
[mysqld1]
pid-file = /var/run/mysqld/mysqld1.pid
socket = /var/run/mysqld/mysqld1.sock
port = 3306
datadir = /var/lib/mysql1
user = mysql
log = /var/log/mysql1.log
key_buffer = 16M
max_allowed_packet = 16M
thread_stack = 192K
thread_cache_size = 8
myisam-recover = BACKUP
query_cache_limit = 1M
query_cache_size = 16M
expire_logs_days = 10
max_binlog_size = 100M
[mysqld2]
pid-file = /var/run/mysqld/mysqld2.pid
socket = /var/run/mysqld/mysqld2.sock
port = 3307
datadir = /var/lib/mysql2
user = mysql
log = /var/log/mysql2.log
key_buffer = 16M
max_allowed_packet = 16M
thread_stack = 192K
thread_cache_size = 8
myisam-recover = BACKUP
query_cache_limit = 1M
query_cache_size = 16M
expire_logs_days = 10
max_binlog_size = 100M
5.运行多个实例（mysqld_multi的参数意义可以看这个）：
mysqld_multi start 1,2
*6.查看是否正常运行：
netstat -nltp | grep mysql
7.修改root密码（这里设为123456，需要指定socket）
mysqladmin -uroot password '123456' -S /var/run/mysqld/mysqld1.sock
mysqladmin -uroot password '123456' -S /var/run/mysqld/mysqld2.sock
8.添加关闭mysql的权限
mysql -uroot -pime@mysql -S /var/run/mysqld/mysqld1.sock < "GRANT SHUTDOWN ON *.* TO 'root'@'localhost' IDENTIFIED BY '11111'"
mysql -uroot -pime@mysql -S /var/run/mysqld/mysqld2.sock < "GRANT SHUTDOWN ON *.* TO 'root'@'localhost' IDENTIFIED BY '11111'"
*9.关闭多个实例（用上面指定的账户关闭）
mysqld_multi --user=root --password=11111 stop 1,2