I’ve had trouble in the past setting up Linux-HA a.k.a heartbeat to create a redundant front-end for a web service. The HA documentation is quite thorough and detailed, but it’s lacking realistic examples to get a working system up and running. This is a quick guide to creating a 2-way cluster with one or more floating IP addresses and automatic failover on Ubuntu 9.04. I also include a quick config for pound, a reverse proxy / load balancer.
This article on highscalability.com is a really excellent rundown of some of the options available for scaling a site to the heights of Digg. Ironically enough, at the time of writing the highscalabilitycom web server shows this error:
Unable to connect to database server
The MySQL error was: User highscal_admin already has more than ‘max_user_connections’ active connections.
I can point them at this really good article on how to avoid problems like this… oh, wait…