Home / server / Questions / 354579
Accepted
user53864
Asked: 2012-01-29 09:09:56 +0800 CST

How do I do IP Failover for my Public IP address with Linux HA

  • 772

I did a lot of experiment with heartbeat, corosync and pacemaker for IP FailOver which I have to do with Public IP. I did more than one ip failover(VIPs) with two nodes, also with three nodes BUT using Private IP(s) as VIPs.

I tried this using vbox virtual machines and everything was ok as far as I was doing with Private IP addresses but when I started thinking of doing for Public IP failover(which I'm assigned from ISP), I got stuck, confused questioning myself.

I have some machines in LAN interconnected with the help of Home Router on which DHCP enabled. I could not go further thinking how do I do failover for the Public IP which I am assigned.

My questions is,

How do I do the same failover for the Public IP address which I'm assigned? with one more router? if yes how?

Any help is greatly appreciated. Thanks!

Update

Related to my router:

  • Ok, need two routers, how to know/buy if router supports clustering?
  • Do I really need two ISP(public ip) links to failover the single public ip?.
  • After all, I think I should do a Port Forwarding on a router to VIP(private ip) which I have configured for failover using heartbeat on servers. How should I proceed for another VIP? is that on another router?
router ip port-forwarding failover ubuntu-10.04

2 Answers

  1. Best Answer

    So you need a method to survive some kind of failure. Failure of what?

    Failure of your router

    You need:

    • a cluster of two routers; pick ones that support clustering (passive-active is enough)
    • two physical links from your ISP
    • all servers should connect independently to both routers

    Failure of either your router or ISP (done with DNS)

    You need:

    • two ISPs
    • two "public" IPs (that is, Internet IPs)
    • a DNS server with
      • round-robin,
      • and a very small TTL
      • and capable of automatic deletion of IP record when that IP becomes unavailable

    Failure of either your router or ISP (done with BGP)

    You need:

    • two ISPs
      • each ISP to support BGP protocol - usually the cost is prohibitive
    • two "public" IPs
    • two routers with BGP support

    With BGP you have much faster failover of incoming traffic than with DNS.

    • 7

  2. Is your goal to stay online in case of modem/router failure? If yes, this gets very complicated in that the IP address assigned to you is assigned to that particular modem.

    If you have a domain name that you are using for this purpose you could get redundant internet service, and a router that can handle multiple WAN ports with failover. Multitec makes a line of routers for this purpose. You can then set up Round-Robin service on the domain with your provider.

    If you do not already have a domain, you could get one from a dynamic dns site like http://no-ip.com or dyn.com. Most of these routers have options in their firmware for keeping a site like this updated.

    • 1