不要再研究 Pacemaker 或 Corosync 了，花了一大堆時間後才發見就算你把系統的自動化做得很好，Failover 也很 smart 但是一旦有問題的時候需要的知識跟管理門檻實在太高了。有的時候簡單的Solution才是最好的，Keepalived 不但設定簡單，而且你會一些Bash scripting的話，基本上功能不會輸給Pacemaker而且還更好學。就讓我用這篇實作來帶你入門吧。

http://blog.unicsolution.com/2015/01/kamailio-high-availability-with.html
請到我的部落格看詳細內容

http://blog.unicsolution.com/2015/01/kamailio-high-availability-with.html

!Configuration File for keepalived

vrrp_script check_sip {
    script       "/etc/keepalived/checksip.sh"
    interval 5   # check every 5 seconds
    fall 2       # require 2 failures for KO
    rise 4       # require 4 successes for OK
}

vrrp_instance SBC_1 {
    state BACKUP
    interface eth0
    virtual_router_id 56
#   priority 100
    nopreempt
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass somepassword
    }
    virtual_ipaddress {
        123.123.123.123/24 brd 123.123.123.255 dev eth0 label eth0:0
    }
    track_script {
        check_sip
    }
    notify_master "/etc/keepalived/master-backup.sh MASTER"
    notify_backup "/etc/keepalived/master-backup.sh BACKUP"
    notify_fault "/etc/keepalived/master-backup.sh FAULT"
}