Keepalived (monitor Heartbeat)

Keepalived is a highly available Web service solution based on the VRRP protocol, which improves the high availability of your Web site.

When a Web server has at least two or more servers running keepalived, and the primary server is down, the backup server takes over the virtual IP and does not stop service because the primary server is down.

Here is the keepalived Heartbeat monitoring implementation (HTTP port test):

First prepare two servers:

192.168.1.110 (Main)

192.168.1.209 (prepared)

1. Download keepalived (two downloads)

# yum Install keepalived 

2, modify the configuration file (main)

# IP Addr

# vim/etc/keepalived/keepalived.conf

! Configuration File for keepalived

global_defs {
   notification_email {
     acassen@firewall.loc
     Failover@firewall.loc
     sysadmin@firewall.loc
   }
   notification_email_from Alexandre.Cassen@firewall.loc
   smtp_server 192.168.200.1
   smtp_connect_timeout
   router_id lvs_devel
}

vrrp_script Chk_ Http_port {
       Script "</dev/tcp/127.0.0.1/81" # Connects and exits
       interval 1                      # Check every
       second Weight-2                       # Default Prio:-2 If connect fails
}
vrrp_instance vi_1 {State
    MASTER
    Interface Eno1 6777736 #如上图所示
    virtual_router_id Wuyi
    priority #大于配置文件
    Advert_int 1
    authentication {
        Auth _type Pass
        auth_pass 1111# security Validation
    }
    virtual_ipaddress {
        192.168.1.190 #虚拟ip
    }

Track_ Script {
        chk_http_port
    }
}

3, modify the configuration file (from)

! Configuration File for keepalived

global_defs {
   notification_email {
     acassen@firewall.loc
     Failover@firewall.loc
     sysadmin@firewall.loc
   }
   notification_email_from Alexandre.Cassen@firewall.loc
   smtp_server 192.168.200.1
   smtp_connect_timeout
   router_id lvs_devel
}

vrrp_script Chk_ Http_port {
       Script "</dev/tcp/127.0.0.1/81" # Connects and exits
       interval 1                      # Check every
       second Weight-2                       # Default Prio:-2 If connect fails
}
vrrp_instance vi_1 {State
    BACKUP #区分
    interface E no16777736 #如上图所示
    virtual_router_id
    priority #需要比主小
    Advert_int 1
    Authentication {
        Auth_type Pass
        auth_pass 1111  #安全验证
    }
    virtual_ipaddress {
        192.168.1.190 #虚拟ip
    }

    track_script {
        chk_http_port
    }
}

Two servers are subject to change, other than individual locations

4, after the modification of the two configuration files need to reboot

# systemctl Restart keepalived

5, at this time the virtual IP in the primary server display

# IP Addr

If the HTTP service in the primary server suddenly hangs up, the virtual IP will be displayed on the backup server, which means that keepalived detects the 81 port stop, and then transfers the service from the primary server to the backup to continue running.