MySQL之——基于Keepalived实现双机HA

1、环境描述：

    OS：CentOS6.5_X64
    MASTER：192.168.0.202
    BACKUP：192.168.0.203
    VIP：192.168.0.204

2、配置两台Mysql主主同步

关于MySQL的安装大家也可以参考《 MySQL之——CentOS6.5 编译安装MySQL5.6.16 》，主主同步在主从同步的基础上将从服务器配置为之前主服务器的Master，相当于在原来主从同步的基础上，将原来的Slave设置为了原来Master的Master，大家也可以参考《MySQL之——MS主从复制(读写分离)实现》 ，设置A为B的Master，B为A的Slave后，然后再将B设置为A的Master,A设置为B的Slave。

[root@masterr ~]# yum install mysql-server mysql -y  
[root@masterr ~]# service mysqld start  
[root@masterr ~]# mysqladmin -u root proot  
[root@masterr ~]# vi /etc/my.cnf  #开启二进制日志，设置id  
[mysqld]  
server-id = 1                    #backup这台设置2  
log-bin = mysql-bin  
binlog-ignore-db = mysql,information_schema       #忽略写入binlog日志的库  
auto-increment-increment = 2             #字段变化增量值  
auto-increment-offset = 1              #初始字段ID为1  
slave-skip-errors = all                       #忽略所有复制产生的错误       
[root@masterr ~]# service mysqld restart

#先查看下log bin日志和pos值位置

master配置如下：

[root@ master ~]# mysql -u root -proot  
mysql> GRANT  REPLICATION SLAVE ON *.* TO 'replication'@'192.168.0.%' IDENTIFIED  BY 'replication';  
mysql> flush  privileges;  
mysql> change  master to  
    ->  master_host='192.168.0.203',  
    ->  master_user='replication',  
    ->  master_password='replication',  
    ->  master_log_file='mysql-bin.000002',  
    ->  master_log_pos=106;  #对端状态显示的值  
mysql> start  slave;         #启动同步

backup配置如下：

[root@backup ~]#  mysql -u root -proot  
mysql> GRANT  REPLICATION SLAVE ON *.* TO 'replication'@'192.168.0.%' IDENTIFIED  BY 'replication';  
mysql> flush  privileges;  
mysql> change  master to  
    ->  master_host='192.168.0.202',  
    ->  master_user='replication',  
    ->  master_password='replication',  
    ->  master_log_file='mysql-bin.000002',  
    ->  master_log_pos=106;  
mysql> start  slave;

#主主同步配置完毕，查看同步状态Slave_IO和Slave_SQL是YES说明主主同步成功。

在master插入数据测试下：

在backup查看是否同步成功：

可以看到已经成功同步过去，同样在backup插入到user表数据，一样同步过去，双主就做成功了。

3、配置keepalived实现热备

[root@backup ~]# yum install -y pcre-devel openssl-devel popt-devel #安装依赖包

[root@masterr ~]# wget http://www.keepalived.org/software/keepalived-1.2.7.tar.gz  
[root@masterr ~]# tar zxvf keepalived-1.2.7.tar.gz  
[root@masterr ~]# cd keepalived-1.2.7  
[root@masterr ~]#./configure --prefix=/usr/local/keepalived  
make

#将keepalived配置成系统服务

[root@masterr ~]# cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/  
[root@masterr ~]# cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/  
[root@masterr ~]# mkdir /etc/keepalived/  
[root@masterr ~]# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/  
[root@masterr ~]# cp /usr/local/keepalived/sbin/keepalived /usr/sbin/

[root@masterr ~]# vi /etc/keepalived/keepalived.conf  
! Configuration File forkeepalived  
global_defs {  
notification_email {  
test@sina.com  
 }  
notification_email_from  admin@test.com  
smtp_server 127.0.0.1  
smtp_connect_timeout 30  
router_id MYSQL_HA      #标识，双主相同  
 }  
vrrp_instance VI_1 {  
 state BACKUP           #两台都设置BACKUP  
 interface eth0  
 virtual_router_id 51       #主备相同  
 priority 100           #优先级，backup设置90  
 advert_int 1  
 nopreempt             #不主动抢占资源，只在master这台优先级高的设置，backup不设置  
 authentication {  
 auth_type PASS  
 auth_pass 1111  
 }  
 virtual_ipaddress {  
 192.168.0.204  
 }  
}  
virtual_server 192.168.0.204 3306 {  
 delay_loop 2  
 #lb_algo rr              #LVS算法，用不到，我们就关闭了  
 #lb_kind DR              #LVS模式，如果不关闭，备用服务器不能通过VIP连接主MySQL  
 persistence_timeout 50  #同一IP的连接60秒内被分配到同一台真实服务器  
 protocol TCP  
 real_server 192.168.0.202 3306 {   #检测本地mysql，backup也要写检测本地mysql  
 weight 3  
 notify_down /usr/local/keepalived/mysql.sh    #当mysq服down时，执行此脚本，杀死keepalived实现切换  
 TCP_CHECK {  
 connect_timeout 3    #连接超时  
 nb_get_retry 3       #重试次数  
 delay_before_retry 3 #重试间隔时间  
  }  
}

[root@masterr ~]# vi /usr/local/keepalived/mysql.sh  
#!/bin/bash  
pkill keepalived  
[root@masterr ~]# chmod +x /usr/local/keepalived/mysql.sh  
[root@masterr ~]# /etc/init.d/keepalived start

#backup服务器只修改priority为90、nopreempt不设置、real_server设置本地IP。

#授权两台Mysql服务器允许root远程登录，用于在其他服务器登陆测试！

mysql> grant all on *.* to'root'@'192.168.0.%' identified by 'root';  
mysql> flush privileges;

4、测试高可用性

1)通过Mysql客户端通过VIP连接，看是否连接成功。
2)停止master这台mysql服务，是否能正常切换过去，可通过ip addr命令来查看VIP在哪台服务器上。

3)可通过查看/var/log/messges日志，看出主备切换过程
4)master服务器故障恢复后，是否主动抢占资源，成为活动服务器。
注意：服务启动的顺序：先启动MySQL,后启动Keepalived。

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