keepalived(热备份)

Keepalived的作用是检测web服务器的状态，如果有一台web服务器死机，或工作出现故障，Keepalived将检测到，并将有故障的web服务器从系统中剔除，让没问题的服务器顶上，当web服务器工作正常后再接过去原来的服务

MASTER主机：

# tar zxf keepalived-1.1.19.tar.gz
# cd keepalived-1.1.19
# ./configure --prefix=/usr/local/keepalived --with-kernel-dir=/usr/src/kernels/2.6.18-164.el5-i686/         
# make && make intall

# cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/
# cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
# cp /usr/local/keepalived/sbin/keepalived /usr/sbin/
# mkdir /etc/keepalived
# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/

# vi /etc/keepalived/keepalived.conf

! Configuration File for keepalived
global_defs {
   notification_email {
yang@126.com      (当IP发生迁移等事件的时候发送邮件到指定邮箱)
   }
   notification_email_from root@yang.com      (邮件发送方)
   smtp_server 127.0.0.1                (邮件外发服务器地址)
   smtp_connect_timeout 30              (邮件超时时间为30秒)
   router_id LVS_DEVEL                  (一个实例的标识)

}             
vrrp_instance VI_1 { 
    State MASTER        (设置服务器模式,注要大写)
    interface eth0      (实例网卡,也就是提供服务的网卡)
    virtual_router_id 51

    priority 100        (设定权值为100 主备之间的权值差最好大于50  权值范围为0~255)

    advert_int 1        （检查时间为1秒）
    authentication {        （认证方式为密码认证）
        auth_type PASS
        auth_pass 1111
}

    virtual_ipaddress {
     192.168.1.20          (192.168.1.20并不存在)       
    }
   
}

后面的内容不用改

:wq

启动keepalived

# service keepalived start

开机自启动

# chkconfig --add keepalived

# chkconfig --level 35 keepalived on

# ip a

2: eth0:  mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:01:11:2a brd ff:ff:ff:ff:ff:ff
    inet 192.168.200.128/24 brd 192.168.200.255 scope global eth0
    inet 192.168.1.20/32 scope global eth0
    inet6 fe80::20c:29ff:fe01:112a/64 scope link

其它主机ping192.168.1.20是可以ping通的，访问页面也是可以的

BACKUP主机：

其步骤和MASTER主机步骤一样，只需把MASTER改成BACKUP 及 priority 100 改为50即可

验证：

在MASTER主机未宕之前，BACKUP主机ip a 是不会显示192.168.1.20的，访问192.168.1.20显示的是MASTER主机的页面
而在MASTER主机宕后，BACKUP主机ip a 就可以看到192.168.1.20了，再访问192.168.1.20显示的就是BACKUP主机的页面了