keepalive实现web服务器active/passive

https://github.com/acassen/keepalived/blob/v1.2.13/doc/keepalived.conf.SYNOPSIS
http://ngyuki.hatenablog.com/entry/2016/04/04/193949

master

global_defs {
   notification_email {
     sysadmin@mydomain.com
   }
   notification_email_from sysadmin@mydomain.com
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id us-1-219
}

vrrp_script chk_http_port {
    script "</dev/tcp/127.0.0.1/80"
    interval 1
    fall 2
    rise 1
}

vrrp_sync_group sync_group_1 {
    group {
        private
        public
    }
}

vrrp_instance private {
    state MASTER
    interface em1
    virtual_router_id 110
    priority 200
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass cce068f9
    }
    virtual_ipaddress {
        10.150.1.20/24 dev em1 label em1:0
    }
    track_script {
       chk_http_port weight 0
    }
}

vrrp_instance public {
    state MASTER
    interface em2
    virtual_router_id 119
    priority 200
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass cce068f9
    }
    virtual_ipaddress {
        169.169.34.29/27 dev em2 label em2:0
    }
    track_script {
       chk_http_port weight 0
    }
}

backup

global_defs {
   notification_email {
     sysadmin@mydomain.com
   }
   notification_email_from sysadmin@mydomain.com
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id us-1-220
}

vrrp_script chk_http_port {
    script "</dev/tcp/127.0.0.1/80"
    interval 1
    fall 2
    rise 1
}

vrrp_sync_group sync_group_1 {
    group {
        private
        public
    }
}

vrrp_instance private {
    state BACKUP
    interface em1
    virtual_router_id 110
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass cce068f9
    }
    virtual_ipaddress {
        10.150.1.20/24 dev em1 label em1:0
    }
    track_script {
       chk_http_port weight 0
    }
}

vrrp_instance public {
    state BACKUP
    interface em2
    virtual_router_id 119
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass cce068f9
    }
    virtual_ipaddress {
        169.169.34.29/27 dev em2 label em2:0
    }
    track_script {
       chk_http_port weight 0
    }
}

备注

#1 ip存活检测与服务存活检测
#2 同步组功能，内外网卡有一块有问题，vip就切换
#3 主机的state设置为MASTER，备机的state设置为BACKUP，priority来决定谁为主，谁为从
#4 主备机同一个vrrp_instance的id要一致

测试

#219 
ifdown em1 or ifdown em2，2个vip从219飘到220
ifdown em2 or ifdown em2，2个vip又飘回219

/etc/init.d/nginx stop，2个vip从219飘到220
/etc/init.d/nginx start，2个vip又飘回219