下面是从网上看到的Mysql双主+keepalived实现HA的介绍,搭建双主是没有问题的,问题在于如果互为主从的一台机器如果挂掉了,并且另外一台机器的数据还不是从库中最新的,那么这个时候就会出问题。并且,两台互为主从的数据库二进制日志必须完全一致。要保证这一点,就必须在安装应用的时候都要规划好。
关于MySQL-HA,目前有多种解决方案,比如heartbeat、drbd、mmm、共享存储,但是它们各有优缺点。heartbeat、drbd配置较为复杂,需要自己写脚本才能实现MySQL自动切换,对于不会脚本语言的人来说,这无疑是一种脑裂问题;对于mmm,生产环境中很少有人用,且mmm 管理端需要单独运行一台服务器上,要是想实现高可用,就得对mmm管理端做HA,这样无疑又增加了硬件开支;对于共享存储,个人觉得MySQL数据还是放在本地较为安全,存储设备毕竟存在单点隐患。使用MySQL双master+keepalived是一种非常好的解决方案,在MySQL-HA环境中,MySQL互为主从关系,这样就保证了两台MySQL数据的一致性,然后用keepalived实现虚拟IP,通过keepalived自带的服务监控功能来实现MySQL故障时自动切换。
下面,我把即将上线的一个生产环境中的架构与大家分享一下,看一下这个架构中,MySQL-HA是如何实现的,环境拓扑如下
MySQL-VIP:192.168.1.200
MySQL-master1:192.168.1.201
MySQL-master2:192.168.1.202
OS版本:CentOS 5.4
MySQL版本:5.0.89
Keepalived版本:1.1.20
一、MySQL master-master配置
1、修改MySQL配置文件
两台MySQL均如要开启binlog日志功能,开启方法:在MySQL配置文件[MySQLd]段中加上log-bin=MySQL-bin选项
两台MySQL的server-ID不能一样,默认情况下两台MySQL的serverID都是1,需将其中一台修改为2即可
2、将192.168.1.201设为192.168.1.202的主服务器
在192.168.1.201上新建授权用户
MySQL> grant replication slave on *.* to ‘replication‘@‘%‘ identified by ‘replication‘;
Query OK, 0 rows affected (0.00 sec)
MySQL> show master status;
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| MySQL-bin.000003 | 374 | | |
+------------------+----------+--------------+------------------+
1 row in set (0.00 sec)
在192.168.1.202上将192.168.1.201设为自己的主服务器
MySQL> change master to master_host=‘192.168.1.201‘,master_user=‘replication‘,master_password=‘replication‘,master_log_file=‘MySQL-bin.000003‘,master_log_pos=374;
Query OK, 0 rows affected (0.05 sec)
MySQL> start slave;
Query OK, 0 rows affected (0.00 sec)
MySQL> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.1.201
Master_User: replication
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: MySQL-bin.000003
Read_Master_Log_Pos: 374
Relay_Log_File: MySQL-master2-relay-bin.000002
Relay_Log_Pos: 235
Relay_Master_Log_File: MySQL-bin.000003
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 374
Relay_Log_Space: 235
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
1 row in set (0.00 sec)
3、将192.168.1.202设为192.168.1.201的主服务器
在192.168.1.202上新建授权用户
MySQL> grant replication slave on *.* to ‘replication‘@‘%‘ identified by ‘replication‘;
Query OK, 0 rows affected (0.00 sec)
MySQL> show master status;
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| MySQL-bin.000003 | 374 | | |
+------------------+----------+--------------+------------------+
1 row in set (0.00 sec)
在192.168.1.201上,将192.168.1.202设为自己的主服务器
MySQL> change master to master_host=‘192.168.1.202‘,master_user=‘replication‘,master_password=‘replication‘,master_log_file=‘MySQL-bin.000003‘,master_log_pos=374;
Query OK, 0 rows affected (0.05 sec)
MySQL> start slave;
Query OK, 0 rows affected (0.00 sec)
MySQL> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.1.202
Master_User: replication
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: MySQL-bin.000003
Read_Master_Log_Pos: 374
Relay_Log_File: MySQL-master1-relay-bin.000002
Relay_Log_Pos: 235
Relay_Master_Log_File: MySQL-bin.000003
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 374
Relay_Log_Space: 235
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
1 row in set (0.00 sec)
4、MySQL同步测试
如上述均正确配置,现在任何一台MySQL上更新数据都会同步到另一台MySQL,MySQL同步在此不再演示
二、keepalived安装及配置
1、192.168.1.201服务器上keepalived安装及配置
安装keepalived
#tar zxvf keepalived-1.1.20.tar.gz
#cd keepalived-1.1.20
#./configure --prefix=/usr/local/keepalived --with-kernel-dir=/usr/src/kernels/2.6.18-164.el5-i686
#make && make install
配置keepalived
我们自己在新建一个配置文件,默认情况下keepalived启动时会去/etc/keepalived目录下找配置文件
#mkdir /etc/keepalived
#vi /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
luwenju@live.cn
}
notification_email_from luwenju@live.cn
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id MySQL-ha
}
vrrp_instance VI_1 {
state BACKUP #两台配置此处均是BACKUP
interface eth0
virtual_router_id 51
priority 100 #优先级,另一台改为90
advert_int 1
nopreempt #不抢占,只在优先级高的机器上设置即可,优先级低的机器不设置
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.1.200
}
}
virtual_server 192.168.1.200 3306 {
delay_loop 2 #每个2秒检查一次real_server状态
lb_algo wrr #LVS算法
lb_kind DR #LVS模式
persistence_timeout 60 #会话保持时间
protocol TCP
real_server 192.168.1.201 3306 {
weight 3
notify_down /usr/local/MySQL/bin/MySQL.sh #检测到服务down后执行的脚本
TCP_CHECK {
connect_timeout 10 #连接超时时间
nb_get_retry 3 #重连次数
delay_before_retry 3 #重连间隔时间
connect_port 3306 #健康检查端口
}
}
编写检测服务down后所要执行的脚本
#vi /usr/local/MySQL/bin/MySQL.sh
#!/bin/sh
pkill keepalived
#chmod +x /usr/local/MySQL/bin/MySQL.sh
注:此脚本是上面配置文件notify_down选项所用到的,keepalived使用notify_down选项来检查real_server的服务状态,当发现real_server服务故障时,便触发此脚本;我们可以看到,脚本就一个命令,通过pkill keepalived强制杀死keepalived进程,从而实现了MySQL故障自动转移。另外,我们不用担心两个MySQL会同时提供数据更新操作,因为每台MySQL上的keepalived的配置里面只有本机MySQL的IP+VIP,而不是两台MySQL的IP+VIP
启动keepalived
#/usr/local/keepalived/sbin/keepalived –D
#ps -aux | grep keepalived
测试
找一台局域网PC,然后去ping MySQL的VIP,这时候MySQL的VIP是可以ping的通的
停止MySQL服务,看keepalived健康检查程序是否会触发我们编写的脚本
2、192.168.1.202上keepalived安装及配置
安装keepalived
#tar zxvf keepalived-1.1.20.tar.gz
#cd keepalived-1.1.20
#./configure --prefix=/usr/local/keepalived --with-kernel-dir=/usr/src/kernels/2.6.18-164.el5-i686
#make && make install
配置keepalived
这台配置和上面基本一样,但有三个地方不同:优先级为90、无抢占设置、real_server为本机IP
#mkdir /etc/keepalived
#vi /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
luwenju@live.cn
}
notification_email_from luwenju@live.cn
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id MySQL-ha
}
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 51
priority 90
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.1.200
}
}
virtual_server 192.168.1.200 3306 {
delay_loop 2
lb_algo wrr
lb_kind DR
persistence_timeout 60
protocol TCP
real_server 192.168.1.202 3306 {
weight 3
notify_down /usr/local/MySQL/bin/MySQL.sh
TCP_CHECK {
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 3306
}
}
编写检测服务down后所要执行的脚本
#vi /usr/local/MySQL/bin/MySQL.sh
#!/bin/sh
pkill keepalived
#chmod +x /usr/local/MySQL/bin/MySQL.sh
启动keepalived
#/usr/local/keepalived/sbin/keepalived –D
#ps -aux | grep keepalived
测试
停止MySQL服务,看keepalived健康检查程序是否会触发我们编写的脚本
三、测试
MySQL远程登录测试
我们找一台安装有MySQL客户端的windows,然后登录VIP,看是否能登录,在登录之两台MySQL服务器都要授权允许从远程登录
MySQL> grant all privileges on *.* to ‘root‘@‘%‘ identified by ‘123456‘;
Query OK, 0 rows affected (0.00 sec)
MySQL> flush privileges;
Query OK, 0 rows affected (0.00 sec)
使用客户端登录VIP测试
C:\MySQL\bin>MySQL.exe -uroot -p123456 -h192.168.1.200 -P3306
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 224
Server version: 5.0.89-log Source distribution
Type ‘help;‘ or ‘\h‘ for help. Type ‘\c‘ to clear the current input statement.
MySQL>
● keepalived故障转移测试
※在windows客户端一直去ping VIP,然后关闭192.168.1.201上的keepalived,正常情况下VIP就会切换到192.168.1.202上面去
※开启192.168.1.201上的keepalived,关闭192.168.1.202上的keepalived,看是否能自动切换,正常情况下VIP又会属于192.168.1.201
注:keepalived切换速度还是非常块的,整个切换过程只需1-3秒
● MySQL故障转移测试
※在192.168.1.201上关闭MySQL服务,看VIP是否会切换到192.168.1.202上
※开启192.168.1.201上的MySQL和keepalived,然后关闭192.168.1.202上的MySQL,看VIP是否会切换到192.168.1.201上
下面是用windows客户端连接的MySQL的VIP,在切换时我执行了一个MySQL查询命令,从执行show databases到显示出结果时间为3-5秒(大家可以看到上面有个错误提示,不过不用担心,因为我们的keepalived切换大概为3秒左右,这3秒左右VIP是谁都不属于的)
MySQL> show databases;
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect...
Connection id: 592
Current database: *** NONE ***
+--------------------+
| Database |
+--------------------+
| information_schema |
| MySQL |
| test |
+--------------------+
3 rows in set (9.01 sec)
本文出自 “11426500” 博客,请务必保留此出处http://11436500.blog.51cto.com/11426500/1887018
原文地址:http://11436500.blog.51cto.com/11426500/1887018