keepalived四种状态的变化

keepalived

keepalived会有四种状态的变化，每种状态变化时，都可以调用一个脚本

当进入Master状态时会呼叫	notify_master
当进入Backup状态时会呼叫	notify_backup
当进入Fault(异常)状态呼叫 notify_fault
当Keepalived终止时则呼叫 notify_stop

进入Master状态时增加一个发邮件的操作

#10.185.220.4  /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   router_id wiilead
}
vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 51
    priority 150
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress { 
        10.185.220.5
    }
}

#10.185.220.6  /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   router_id wiilead
}
vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    
    #节点变为master时执行，     重启了次服务器才生效，不知道为什么
    notify_master /etc/keepalived/send_mail.sh
    
    virtual_ipaddress { 
        10.185.220.5
    }
}


# /etc/keepalived/send_mail.sh
echo "This is message body" | mail -s "This is Title" 1234@qq.com

sudo yum -y install mailx  postfix
sudo vim /etc/postfix/main.cf
inet_protocols = ipv4

sudo systemctl start postfix
echo "This is message body" | sudo mail -s "This is Title" 1234@qq.com

keepalived之vrrp_script
根据业务进程的运行状态决定是否需要进行主备切换

VRRP scripts的实现：分两步：

1、先定义一个脚本
vrrp_script SCRIPT_NAME_1 {             #定义一个检测脚本，在global_defs 之外配置
    script <STRING>|<QUOTED-STRING>     # shell命令或脚本路径
    interval <INTEGER>                  # 间隔时间，单位为秒，默认1秒
    timeout <INTEGER>                   # 超时时间
    weight <INTEGER:-254..254>          # 权重，当脚本成功或失败对当前节点的优先级是增加还是减少，这个值会与定义的优先级做加法例：-80时则为priority+（-80）
    fall <INTEGER>                      #脚本几次失败转换为失败
    rise <INTEGER>                      # 脚本连续监测成果后，把服务器从失败标记为成功的次数
    user USERNAME [GROUPNAME]           # 执行监测的用户或组
    init_fail                           # 设置默认标记为失败状态，监测成功之后再转换为成功状态
}

2、调用脚本
track_script {
    SCRIPT_NAME_1
    ...
}

vrrp_script checkng
{
    script "/etc/check.sh"
    interval 3
    weight -20

}

vrrp_instance test
{
    ....
    
    state MASTER
    priority 80
    nopreempt #不抢占， 切换成back后不会因为权重再次抢回master角色

    track_script
    {
        checkng
    }

    ....
}


#/etc/check.sh 
#!/bin/bash
count = `ps aux | grep -v grep | grep haproxy | wc -l`
if [ $count > 0 ]; then
    exit 0   #如果脚本执行结果为0，并且weight配置的值大于0，则优先级相应的增加
else
    exit 1
fi