backup - Can you recommend a failover solution for setups running multiple VPSes?

Here's what I have to work with:

• Root access to VPSes with different hosting companies that run CentOS only
  
  
  
  
  • Two dedicated nameservers with over 100 zone entries
  
  
  • Several webservers hosting the same content
  
  

The failover solutions I've found either require hardware, clustering in the same network, and other options that I can't access with my VPS setup. And paid DNS failover services are too expensive for the number of domains I have.

It seems implementing DNS failover myself is my best option, though the consensus is that it's not a very good option. Are there ANY other solutions I'm missing? Thanks.

Answer

You could use Linux IP Virtual Server using tunneling. No need for the "real servers" (webservers) to be on the same subnet.

The ipip encapsulated packages will be ordinary packages that can be firewalled and forwarded.

http://www.linuxvirtualserver.org/VS-IPTunneling.html

keepalived is a great tool to handle the service checks and adding/removing failed "real servers"