keepalived 实战

两个节点：10.0.2.18   和 10.0.2.19

1、安装：yum install -y keepalived

2、查看配置文件位置：rpm -qc keepalived

3、修改配置文件：

10.0.2.18上的配置文件：
global_defs {
  router_id zcylb
}
vrrp_instance VI_1 {
  state MASTER
  interface enp0s3
  unicast_peer {
      10.0.2.19
  }
  virtual_router_id 51
  priority 100 advert_int 1
  authentication {
    auth_type PASS
    auth_pass 1111
  }
  virtual_ipaddress {
        10.0.2.250 dev enp0s3    
  }
}

其中 10.0.2.250 是我随便设的一个没有被使用的ip，因为我的网卡叫enp0s3，所以配置文件里写的是enp0s3

10.0.2.19上的配置文件：
global_defs {
  router_id zcylb
}
vrrp_instance VI_1 {
  state BACKUP
  interface enp0s3
  unicast_peer {
      10.0.2.18
  }
  virtual_router_id 51
  priority 90
  advert_int 1
  authentication {
    auth_type PASS
    auth_pass 1111
  }
  virtual_ipaddress {
      10.0.2.250 dev enp0s3
  }
}

4、启动keepalived

service keepalived start

5、查看效果

 

 6、停掉master的keepalived

service keepalived stop  ， 发现虚拟ip漂移了

注：在启停keepalived时，也可以查看日志 

tail -f /var/log/messages

 ==============

==下面给keepalived加上执行脚本===

==============

10.0.2.18上的配置文件：

global_defs {
  router_id zcylb
  script_user root
}
vrrp_script check_docker 
{
    script "/home/check_docker_by_keep.sh"
    interval 5
    user root
}
vrrp_instance VI_1 {
  state MASTER
  interface enp0s3
  unicast_peer {
      10.0.2.19
  }
  virtual_router_id 51
  priority 100 advert_int 1
  authentication {
    auth_type PASS
    auth_pass 1111
  }
  track_script {
        check_docker
    }
  virtual_ipaddress {
        10.0.2.250 dev enp0s3
  }
}


========

10.0.2.19上的配置文件

global_defs {
router_id zcylb
script_user root
}
vrrp_script check_docker {
script "/home/check_docker_by_keep.sh"
interval 5
}
vrrp_instance VI_1 {
state BACKUP
interface enp0s3
unicast_peer {
10.0.2.18
}
virtual_router_id 51
priority 90
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
check_docker
}
virtual_ipaddress {
10.0.2.250 dev enp0s3
}
}

[root@zcy ~]# cat /home/check_docker_by_keep.sh 
#!/bin/bash

A=$(service docker status | grep ' active (running)')
if [ "${A}" ] 
then
    echo "runing zcy"
    echo "runing zcy" >> /home/mylog
else
    #service keepalived stop
    echo "not runing" >> /home/mylog
    service keepalived stop

fi 

当需要keepalived执行脚本时，需要脚本有可执行权限，且要关闭SELINUX

sudo setenforce 0
sudo sed -i ‘s/^SELINUX=enforcing$/SELINUX=permissive/’ /etc/selinux/config

判断脚本可以被成功执行：

grep 'VRRP_Script(check_docker) succeeded' /var/log/messages

查看绑定效果

ip add show