Well, if your nodes are what contains the CGI program, and the servers themselves manage themselves in terms of who is active, inactive and various other statistics such as load...

Think of it as writing two programs that share resources on one machine. All clusters do is distribute load, so if your program can't work on one machine with two copies running, then two machines running a copy each won't work.

You may have to worry about, as in regular multi process/thread code, locking of resources. If it's db, file, anything else...