通过使用这个keepalived服务，每当服务器为每个VRRP实例从主服务器切换到从服务器或从服务器切换到主服务器时，都会通知用户。
下面的步骤将如何启用电子邮件提醒在Keepalived。

启用电子邮件提醒的步骤:

步骤1:编辑保存的配置文件

# /etc/keepalived/keepalived.conf

步骤2:在全局设置中添加以下条目

global_defs {
	notification_email {
        Hyman@theitroad
	}
  notification_email_from Hyman@theitroad
  smtp_server mail.theitroad.com
  smtp_connect_timeout 30
# ...... Other configuration here .......
}

步骤3:在每个VRRP实例中添加smtp_alert

vrrp_instance VI_1 {
# ...... Other configuration here .......
smtp_alert
# ...... Other configuration here .......
}

步骤4:重新启动keepalive服务

# service keepalived restart

步骤5:邮件提示如下
当VRRP实例进入主状态时

Subject: [hostname] VRRP Instance VI_1 - Entering MASTER state
Message: => VRRP Instance is now owning VRRP VIPs <=

当VRRP实例进入从属状态时

Subject: [hostname] VRRP Instance VI_1 - Entering SLAVE state
Message: => VRRP Instance is nolonger owning VRRP VIPs <=