Mysql + keepalive高可用搭建

系统环境：centos6.8
Ip：192.168.137.36 主库
192.168.137.38 从库

VIP(虚拟ip/浮动ip):192.168.137.100

软件版本：mysql 5.7.20
Keepalived 1.2.13

主从搭建略
Mysql1
vim /etc/my.cnf
binlog-do-db=test
log-bin=mysql-bin
server-id=1
gtid-mode=ON
enforce-gtid-consistency

Mysql2
Vim /etc/my.cnf
gtid-mode=ON
enforce-gtid-consistency
log-bin=mysql-bin
log-slave-updates=ON
server-id=3
binlog-do-db=test

安装keepalived
yum install keepalived

在192.168.137.36主库修改keepalived的配置文件
注意：加颜色部分为修改部分

[root@zabbix ~]# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs{
notification_email {
root@localhost
}
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
#VIP1
vrrp_instance VI_1 {
state BACKUP
interface eth0
lvs_sync_daemon_inteface eth0
virtual_router_id 151
priority 100
advert_int 5
nopreempt
authentication {
auth_type PASS
auth_pass 2222
}
virtual_ipaddress {
192.168.137.100
}
}
virtual_server 192.168.137.100 3306 {
delay_loop 6
lb_algo wrr
lb_kind DR
persistence_timeout 60
protocol TCP
real_server 192.168.137.36 3306 {
weight 100
notify_down /data/sh/mysql.sh
TCP_CHECK {
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 3306
}
}
}

保存退出
在192.168.137.38从库修改keepalived的配置文件
[root@localhost sh]# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs{
notification_email {
root@localhost
}
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
#VIP1
vrrp_instance VI_1 {
state BACKUP
interface eth0
lvs_sync_daemon_inteface eth0
virtual_router_id 151
priority 98
advert_int 5
nopreempt
authentication {
auth_type PASS
auth_pass 2222
}
virtual_ipaddress {
192.168.137.100
}
}
virtual_server 192.168.137.100 3306 {
delay_loop 6
lb_algo wrr
lb_kind DR
persistence_timeout 60
protocol TCP
real_server 192.168.137.38 3306 {
weight 98
notify_down /data/sh/mysql.sh
TCP_CHECK {
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 3306
}
}
}
保存退出
上面的配置简单说明：
state BACKUP  表示为备模式，nopreempt 为不抢占，双方都配为备模式，并且不抢占，可以避免“脑裂”问题，priority 100 为权重，数字越高，权重越高，当双方都配为BACKUP模式，并且配置nopreempt时，keepalived靠这个数字来判断谁是主，谁是备
主从都要创建/data/sh/mysql.sh脚本
mkdir /data/sh
vim /data/sh/mysql.sh 加入以下内容：
#！/bin/bash
/etc/init.d/keepalived  stop
 
chmod  755  /data/sh/mysql.sh
modprobe  ip_vs  #加载ip_vs模块 虚拟IP要用
lsmod |  grep  ip_vs  查看ip_vs模块有没有加载，如果看到下面的内容，就表示加载成功：

/etc/init.d/mysqld  start  #启动mysql
/etc/init.d/keepalive  start   #启动keepalived
在36上的操作和38上一样，只是keepalived.conf配置文件里priority 100 改为 priority 98
 
real_server 192.168.137.36 改为 real_server 192.168.137.38其他不变。
 
查看VIP情况命令: ip a

 
至此mysql的主从高可用就做好了，可以在36上测试挺掉mysql服务，看看vip会不会漂移到38上，一般来说都是没问题的，如果有问题，请检查你的配置，步骤是不是有错误，还有selinux，防火墙是否关闭等