mysqld_multi,mysql_install_db配置多实例出错

ubuntu8.04~8.10安装默认的mysql,不能运行mysql_install_db,不能使用mysqld_multi的罪魁是AppArmor,什么是AppArmor(传送门),不能访问的出错结果是因为apparmor控制了对multi实例的数据目录的访问权限
出错代码：

>> sudo mysql_install_db --datadir=/var/lib/mysql1 --no-defaults --user=mysql
Installing MySQL system tables...
100304 22:34:18 [Warning] Can't create test file /var/lib/mysql1/PB.lower-test
100304 22:34:18 [Warning] Can't create test file /var/lib/mysql1/PB.lower-test
ERROR: 1005 Can't create table 'db' (errno: 13)
100304 22:34:18 [ERROR] Aborting

解决办法：
编辑/etc/apparmor.d/usr.sbin.mysqld这个文件，可以看到默认apt-get安装的mysql对应的数据目录和日志以及socket,pid文件的权限都是存在的，如法炮制,修改配置文件如下:

/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,

修改完这个文件后sudo /etc/init.d/apparmor restart,重启apparmor

继续运行 sudo mysql_install_db –datadir=/var/lib/mysql1 –no-defaults –user=mysql
这样就能安装mysql的系统数据文件到/var/lib/mysql1下面了

配置多个实例很简单:编辑/etc/mysql/my.cnf

[mysqld_multi]
mysqld = /usr/bin/mysqld_safe
mysqladmin = /usr/bin/mysqladmin
user = root
password = 123

[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

[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

运行sudo mysqld_multi start 1,2 –no-log，就能见到终端输出正确的启动信息了

~/home/pb$ netstat -lt | grep 33
tcp 0 0 *:3307 *:* LISTEN
tcp 0 0 *:3308 *:* LISTEN

http://www.neocanable.com/error-for-mysql-multi-and-mysql-install-db/