host1与host3互为主从，即host1为host3的主机，同时也为host3的从机
host1 192.168.203.131
host2 192.168.203.132
host3 192.168.203.133
1.安装keepalived
www.keepalived.org
2.注意先清空防火墙
iptalbles -F
3.配置host1与host3互为主从并授权给host2上的登陆
grant all on *.* to identified by '000000' with grant option;
4.配置keealived.conf
! Configuration File for keepalived
host1上：
global_defs {
notification_email {
[email protected]
}
notification_email_from [email protected]
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id test-mysql-ha
}
vrrp_instance VI_1 {
state BACKUP
interface eth3 !当前机器的网络接口名称
virtual_router_id 51
priority 100 !优先级别
nopreempt !重启后也不要拿回主服务权限
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.203.200 !虚拟ip地址，等会在host2上登陆用此ip
}
}
virtual_server 192.168.203.200 3306 { !此端口即为mysql的服务
delay_loop 1
lb_algo wrr
lb_kind DR
persistence_timeout 50
protocol TCP
real_server 192.168.203.131 3306 { !主机的ip地址
weight 1
notify_down /etc/keepalived/mysql.sh
TCP_CHECK {
connect_timeout 10
bingto 192.168.203.200
nb_get_retry 3
delay_before_retry 3
connect_port 3306
}
}
host3上只需将上面加黑的部分做相应的更改并去掉nopreempt 即可
/etc/keepalived/mysql.sh的内容为：
#!/bin/bash
pkill keepalived
5.host1与host3开启keepalived，在host2上执行登陆mysql -h 192.168.203.200 -ureplmonitor -p （此host为虚拟的ip地址）
/etc/init.d/keepalived start
6.开始测试，我们将host1上的mysql停止
[root@host1 keepalived]# /etc/init.d/mysql stop
Shutting down MySQL............ SUCCESS!
[root@host1 keepalived]# ps -ef | grep keepalived
root 5409 5115 0 00:51 pts/2 00:00:00 grep keepalived
Shutting down MySQL............ SUCCESS!
[root@host1 keepalived]# ps -ef | grep keepalived
root 5409 5115 0 00:51 pts/2 00:00:00 grep keepalived
在host3上查询可知host3已经接管过虚拟的主机
我们继续在host2上执行操作语句
会首先提示连接失败并重新连接，并得到查询结果，故障失效迁移成功
7.在host3上执行：
mysql> delete from t1 where id in(4,5,6);
Query OK, 3 rows affected (0.01 sec) 在host1上重新开启mysql
mysql> select * from t1;
+------+
| id |
+------+
| 1 |
| 2 |
| 4 |
| 5 |
| 6 |
+------+
5 rows in set (0.00 sec) mysql> start slave;
Query OK, 0 rows affected (0.03 sec) mysql> select * from t1;
+------+
| id |
+------+
| 1 |
| 2 |
+------+
2 rows in set (0.00 sec) 数据全部同步过来，再停掉host3上的mysql，在host1上插入一行数据：
mysql> insert into t1 values(3);
在host2上进行查询：
mysql> select * from testdb.t1;
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect...
Connection id: 5
Current database: *** NONE *** mysql> select * from testdb.t1;
+------+
| id |
+------+
| 1 |
| 2 |
| 3 |
+------+
3 rows in set (0.00 sec)
可见数据也过来了，keepalive可以进行高效的数据迁移工作。