本文介绍了mysql主主同步复制中，使用keepalived进行故障切换的配置方法，配置虚拟IP-VIP，安装配置keepalived，完成单点故障转换切换配置。
在“mysql主主同步复制master-master配置”一文中实现了mysql双主模式，即互相备份。
本节用keepavlied实现单点故障切换。
一、配置虚拟IP-VIP
首先，配置VIP节点IP地址，把每台物理地址执行到虚拟IP。
虚拟IP-VIP为： 192.168.15.181
#vim /etc/sysconfig/network-scripts/ifcfg-
eth0:0
DEVICE=eth0:0
IPADDR=192.168.15.181
# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:0c:29:d8:b3:ca brd ff:ff:ff:ff:ff:ff
inet 192.168.15.178/24 brd 192.168.15.255 scope global eth0
inet 192.168.15.181/32 scope global eth0
inet 192.168.15.181/24 brd 192.168.15.255 scope global secondary eth0:0
inet6 fe80::20c:29ff:fed8:b3ca/64 scope link
valid_lft forever preferred_lft forever
3: sit0: <NOARP> mtu 1480 qdisc noop
link/sit 0.0.0.0 brd 0.0.0.0
二、安装配置keepalived
下载地址：http://www.keepalived.org/software
1)、安装：
#wget http://www.keepalived.org/software/keepalived-1.2.7.tar.gz
#tar -zxvf keepalived-1.2.7.tar.gz
#cd keepalived-1.2.7
#./configure --prefix=/usr/local/keepalived --with-kernel-dir=/usr/src/kernels/2.6.18-128.el5-x86_64/ #kernel目录根据实际修改。
预编译后出现：
Keepalived configuration
------------------------
Keepalived version : 1.2.7
Compiler : gcc
Compiler flags : -g -O2 -DETHERTYPE_IPV6=0x86dd
Extra Lib : -lpopt -lssl -lcrypto
Use IPVS Framework : Yes
IPVS sync daemon support : Yes
IPVS use libnl : No
Use VRRP Framework : Yes
Use VRRP VMAC : No
SNMP support : No
Use Debug flags : No
注意，如果没有用到LVS可以把lvs去掉即：--disable-lvs-syncd --disable-lvs
#make && make install
整理管理文件：
#cp /usr/local/keepalived/sbin/keepalived /usr/sbin/
#cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
#cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/
建立配置文件目录(注意：keepalived的配置文件默认在/etc/keepalived/目录)
#mkdir /etc/keepalived
两台服务器(两个节点)都这样安装即可
2）配置
节点A192.168.15.178配置：
#vim /etc/keepalived/keepalived.conf
global_defs {
notification_email
{
roc@example.com
}
notification_email_from roc@example.com
smtp_server 127.0.0.1
stmp_connect_timeout 30
router_id MySQL-ha
}
vrrp_script chk_mysql {
script "killall -0 mysqld" #检测mysqld进程，也可以替换成检测
脚本
interval 5
}
vrrp_instance VI_1 {
state master #从库配置此处均是slave
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 {
192.168.15.181
}
track_script {
chk_mysql #执行上面的命令
}
}
virtual_server 192.168.15.181 3306 {
delay_loop 6
lb_algo wcl
lb_kind DR
#nat_mask 255.255.255.0
persistence_timeout 50
protocol TCP
real_server 192.168.15.178 3306 {
weight 1
TCP_CHECK {
connect_timeout 10 #(10秒无响应超时)
nb_get_retry 3
delay_before_retry 3
connect_port 3306
}
}
real_server 10.8.10.185 3306 {
weight 1
TCP_CHECK {
connect_timeout 10 #(10秒无响应超时)
nb_get_retry 3
delay_before_retry 3
connect_port 3306
}
}
}
节点192.168.15.185配置：
#vim /etc/keepalived/keepalived.conf
global_defs {
notification_email
{
roc@example.com
}
notification_email_from roc@example.com
smtp_server 127.0.0.1
stmp_connect_timeout 30
router_id MySQL-ha
}
vrrp_script chk_mysql {
script "killall -0 mysqld" #检测mysqld进程，也可以替换成检测脚本
interval 5
}
vrrp_instance VI_1 {
state slave #主库配置此处均是master
interface eth0
virtual_router_id 51
priority 90
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.15.181
}
track_script {
chk_mysql #执行上面的命令
}
}
virtual_server 192.168.15.181 3306 {
delay_loop 6
lb_algo wcl
lb_kind DR
#nat_mask 255.255.255.0
persistence_timeout 50
protocol TCP
real_server 192.168.15.178 3306 {
weight 1
TCP_CHECK {
connect_timeout 10 #(10秒无响应超时)
nb_get_retry 3
delay_before_retry 3
connect_port 3306
}
}
real_server 10.8.10.185 3306 {
weight 1
TCP_CHECK {
connect_timeout 10 #(10秒无响应超时)
nb_get_retry 3
delay_before_retry 3
connect_port 3306
}
}
}
3）、开启服务
#/usr/local/keepalived/sbin/keepalived -D
#ps -aux | grep keepalived
root 15416 0.0 0.0 61148 736 pts/1 S+ 16:43 0:00 grep keepalived
root 31121 0.0 0.0 35832 492 ? Ss Jan22 0:00 keepalived -D
root 31122 0.0 0.0 37924 1372 ? S Jan22 0:00 keepalived -D
root 31125 0.0 0.0 37924 1000 ? S Jan22 0:03 keepalived -D
三、测试单点故障切换是否成功
mysql远程登录测试
客户端登录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 php
cmsv9.* to 'dbuser_do'@'192.168.10.6' identified by '123456';
No connection. Trying to reconnect...
Connection id: 1168
Current database: phpcmsv9
Query OK, 0 rows affected (0.11 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
客户端登录结果：
此时查询的是192.168.15.185的数据库信息，关闭192.168.15.185 Mysql，继续联系数据库。
此时连接的是192.168.15.178的数据库。
keepavlied完成后，测试当master服务器和slave也能自动切换，同步保证数据同步正常。
