为了响应公司需求，打造出更安全的MySQL集群，能够实现mysql故障后切换，研究了几天终于有了成果，一起分享一下。
首先介绍一下这套集群方案实现的功能
1、mysql服务器故障后自动转移，修好后自动切回
2、mysql服务故障自动转移，修好后自动切回
3、可以实现在几秒钟内转移
以下内容均是实验环境，请根据实际情况修改响应参数
MySQL + KeepAlived + LVS 单点写入主主同步高可用架构实验
CentOS 6.3下MySQL主从复制笔记
Linux下的MySQL主主复制
实验环境：
mysql1 ip：10.1.1.20
mysql2 ip：10.1.1.21
mysql vip：10.1.1.25
三台机器均安装centos 6.5 32位（虚拟机环境）
实验开始！！！
一、安装mysql，并打造主主同步。
相信主从同步大家都会做，一样的道理，主主同步就是两台机器互为主的关系，在任何一台机器上写入都会同步。
安装mysql的过程不解释，yum就好啦
配置主主同步
1.配置 /etc/my.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
user=mysql
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
log-bin=binlog #开启binlog功能
log-bin-index=binlog.index
sync_binlog=0
server_id = 1 #两台机器不能重复，一个1 一个2 就好
[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
2.分别在两台机器上配置同步账号
10.1.1.20机器上：
[root@localhost ~]# mysql
Welcome to the MySQL monitor. Commands end with; or \g.
Your MySQL connection id is 2
Server version: 5.0.77-log Sourcedistribution
Type 'help;' or '\h' for help. Type '\c' toclear the buffer.
mysql> GRANT replication slave ON *.* TO'ab'@'%' identified by '123';
Query OK, 0 rows affected (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
10.1.1.21机器上：
[root@localhost ~]# mysql
Welcome to the MySQL monitor. Commands end with; or \g.
Your MySQL connection id is 2
Server version: 5.0.77-log Sourcedistribution
Type 'help;' or '\h' for help. Type '\c' toclear the buffer.
mysql> GRANT replication slave ON *.* TO'ab'@'%' identified by '123';
Query OK, 0 rows affected (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
注:由于本文是实验环境下编写，所以没考虑任何安全性问题，同步账号也是最高权限，请根据实际情况设置响应权限！！
3.设置同步
10.1.1.20机器上:
mysql> flush tables with read lock;
mysql> show master status;
+---------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB |Binlog_Ignore_DB |
+---------------+----------+--------------+------------------+
| binlog.000003 | 365 | | |
+---------------+----------+--------------+------------------+
1 row in set (0.03 sec)
mysql> unlock tables;
Query OK, 0 rows affected (0.03 sec)
10.1.1.21机器上：
mysql> change master tomaster_host='10.1.1.20', master_port=3306, master_user='ab',master_password='123', master_log_file='binlog.000003',master_log_pos=365;
Query OK, 0 rows affected (0.06 sec)
mysql> start slave;
Query OK, 0 rows affected (0.00 sec)
mysql> show slave status \G #执行这命令后 注意观察下面这两个参数，必须要都是yes才行
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
同样的 反过来做相同操作
10.1.1.21机器上:
mysql> flush tables with read lock;
mysql> show master status;
+---------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB |Binlog_Ignore_DB |
+---------------+----------+--------------+------------------+
| binlog.000004 | 207 | | |
+---------------+----------+--------------+------------------+
1 row in set (0.03 sec)
mysql> unlock tables;
Query OK, 0 rows affected (0.03 sec)
10.1.1.20机器上：
mysql> change master tomaster_host='10.1.1.21', master_port=3306, master_user='ab',master_password='123', master_log_file='binlog.000004',master_log_pos=207;
Query OK, 0 rows affected (0.06 sec)
mysql> start slave;
Query OK, 0 rows affected (0.00 sec)
mysql> show slave status \G #执行这命令后 注意观察下面这两个参数，必须要都是yes才行
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
介此，主主同步打造完成，可以简单测试一下，分别在两个机器上写数据 看看会不会同步到另一台机器上
PS：如果报错 Slave_IO_Running: NO 可以检查同步的账号是否创建正常！
二、安装keepalived 并设置监控
keepalived是安装在两台MySQL服务器上的
首先安装keepalived 过程不解释就正常解压安装就好
安装后配置 vim /etc/keepalived/keepalived.conf 内容如下
10.1.1.20的配置文件
! Configuration File for keepalived
global_defs {
notification_email {
acassen@firewall.loc
failover@firewall.loc
sysadmin@firewall.loc
}
notification_email_from Alexandre.Cassen@firewall.loc
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
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 {
10.1.1.25
}
}
virtual_server 10.1.1.25 3306 {
delay_loop 6
lb_algo wrr
lb_kind DR
persistence_timeout 50 #会话保持时间
protocol TCP
real_server 10.1.1.20 3306 {
weight 3
notify_down /tmp/nimei.sh #检测到mysql服务挂了就执行这个脚本（脚本要自己写哈）
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
}
}
}
10.1.1.21 的配置文件
! Configuration File for keepalived
global_defs {
notification_email {
acassen@firewall.loc
failover@firewall.loc
sysadmin@firewall.loc
}
notification_email_from Alexandre.Cassen@firewall.loc
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
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 {
10.1.1.25
}
}
virtual_server 10.1.1.25 3306 {
delay_loop 6
lb_algo wrr
lb_kind DR
persistence_timeout 50
protocol TCP
real_server 10.1.1.21 3306 {
weight 3
notify_down /tmp/nimei.sh
TCP_CHECK {
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 3306
}
}
}
编写监控mysql服务是否挂了的脚本，按照上面配置文件的位置编写脚本。
vim /tmp/nimei.sh
#!/bin/sh
pkill keepalived
脚本很简单啊 就一句，目的是当keepalived检测到mysql服务挂了之后触发这个脚本，杀死keepalived进程，让另一台机器接管
好 修改后启动keeplived服务
介此整个集群搭建完成
三、测试
找一台机器用虚拟ip连接mysql
[root@localhost html]# mysql -uab -h 10.1.1.25 -p123
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 736
Server version: 5.1.66-log Source distribution
Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>
这样成功连上了，然后你可以任意关闭某台机器，或者某台机器的mysql服务，看看还能��能连上！！