keepalive例子

keepalived

keepalive是保证web服务器24小时不宕机的机制
主和备服务器都装httpd服务
主服务器是1
从服务器是2
[root@master ~]# yum install -y httpd
[root@master ~]# echo 1 > /var/www/html/index.html
[root@backup ~]# yum install -y httpd
[root@backup ~]# echo 2 > /var/www/html/index.html
[root@backup ~]# service httpd start
[root@master ~]# service httpd start
主服务器
[root@master ~]# yum install -y keepalived
[root@master ~]# cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak //备份配置文件
[root@master ~]# vim /etc/keepalived/keepalived.conf
vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 195 //主从认识用的id号  主要用来让主从相互认识用的 下面的密码也是用来相互认识的 就像两个人的ID密码都一样时 主从就相互认识了
    priority 100
    advert_int 1
    authentication {
        auth_type PASS //主从认识用的加密方法
        auth_pass 2222 //主从认识用的密码
    }
    virtual_ipaddress {
        172.16.18.122  //虚拟IP
    }
}

从服务器
[root@backup ~]# yum install -y keepalived
[root@backup ~]# cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak
[root@backup ~]#  vim /etc/keepalived/keepalived.conf
vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id 195
    priority 20
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 2222
    }
    virtual_ipaddress {
        172.16.18.122
    }  
}
[root@master ~]# service keepalived restart
[root@backup ~]# service keepalived restart
测试
用其他机器访问虚拟IP地址
[root@localhost ~]# elinks 172.16.18.122 --dump
 1
 [root@master ~]# service network stop  主服务器网络停掉
 再访问虚拟IP  从服务器开始工作
 [root@localhost ~]# elinks 172.16.18.122 --dump
 2