爲了響應公司需求，打造出更安全的mysql集羣，能夠實現mysql故障後切換，研究了幾天終於有了成果，一起分享一下。
首先介紹一下這套集羣方案實現的功能
1、mysql服務器故障後自動轉移，修好後自動切回
2、mysql服務故障自動轉移，修好後自動切回
3、可以實現在幾秒鐘內轉移
以下內容均是實驗環境，請根據實際情況修改響應參數
生產環境MySQL主主同步主鍵衝突處理 http://www.linuxidc.com/Linux/2013-07/86890.htm
MySQL + KeepAlived + LVS 單點寫入主主同步高可用架構實驗 http://www.linuxidc.com/Linux/2013-05/84002.htm
MySQL 主主同步配置 http://www.linuxidc.com/Linux/2013-05/83815.htm
CentOS 6.3下MySQL主從複製筆記 http://www.linuxidc.com/Linux/2013-06/85983.htm
Linux下的MySQL主主複製 http://www.linuxidc.com/Linux/2013-10/91683.htm
實驗環境：
mysql1 ip：10.1.1.20
mysql2 ip：10.1.1.21
mysql vip：10.1.1.25
三臺機器均安裝centos 6.5 32位（虛擬機環境）
實驗開始！！！
一、安裝mysql，並打造主主同步。
相信主從同步大家都會做，一樣的道理，主主同步就是兩臺機器互爲主的關係，在任何一臺機器上寫入都會同步。
安裝mysql的過程不解釋，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 #開啓binlog功能
log-bin-index=binlog.index
sync_binlog=0
server_id = 1 #兩臺機器不能重複，一個1 一個2 就好
[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
2.分別在兩臺機器上配置同步賬號
10.1.1.20機器上：
[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機器上：
[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:由於本文是實驗環境下編寫，所以沒考慮任何安全性問題，同步賬號也是最高權限，請根據實際情況設置響應權限！！
3.設置同步
10.1.1.20機器上:
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機器上：
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 #執行這命令後 注意觀察下面這兩個參數，必須要都是yes才行
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
同樣的 反過來做相同操作
10.1.1.21機器上:
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機器上：
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 #執行這命令後 注意觀察下面這兩個參數，必須要都是yes才行
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
介此，主主同步打造完成，可以簡單測試一下，分別在兩個機器上寫數據 看看會不會同步到另一臺機器上
PS：如果報錯 Slave_IO_Running: NO 可以檢查同步的賬號是否創建正常！
二、安裝keepalived 並設置監控
keepalived是安裝在兩臺MySQL服務器上的
首先安裝keepalived 過程不解釋就正常解壓安裝就好
安裝後配置 vim /etc/keepalived/keepalived.conf 內容如下
10.1.1.20的配置文件
! Configuration File for keepalived
global_defs {
notification_email {
[email protected]
[email protected]
[email protected]
}
notification_email_from [email protected]
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_instance VI_1 {
state backup #兩臺配置此處均是BACKUP
interface eth0
virtual_router_id 51
priority 100 #優先級，另一臺改爲90
advert_int 1
nopreempt #不搶佔，只在優先級高的機器上設置即可，優先級低的機器不設置
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 #會話保持時間
protocol TCP
real_server 10.1.1.20 3306 {
weight 3
notify_down /tmp/nimei.sh #檢測到mysql服務掛了就執行這個腳本（腳本要自己寫哈）
TCP_CHECK {
connect_timeout 10 #連接超時時間
nb_get_retry 3 #重連次數
delay_before_retry 3 #重連間隔時間
connect_port 3306 #健康檢查端口
}
}
}
10.1.1.21 的配置文件
! Configuration File for keepalived
global_defs {
notification_email {
[email protected]
[email protected]
[email protected]
}
notification_email_from [email protected]
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
}
}
}
編寫監控mysql服務是否掛了的腳本，按照上面配置文件的位置編寫腳本。
vim /tmp/nimei.sh
#!/bin/sh
pkill keepalived
腳本很簡單啊 就一句，目的是當keepalived檢測到mysql服務掛了之後觸發這個腳本，殺死keepalived進程，讓另一臺機器接管
好 修改後啓動keeplived服務
介此整個集羣搭建完成
三、測試
找一臺機器用虛擬ip連接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>