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

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?

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.

Check more discussion of this question.

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