I've been using monit for a while but have run into a bunch of problems. Sometimes it seems to fail to start processes, even if the start commands can be run without problems from the command line. It also has no mechanism to monitor a set of processes like what's needed for mongrel clusters. I looked into mon but wasn't impressed. Then I came across [god](http://god.rubyforge.org/). I think god has a lot of potential but it'll probably be a while before I feel comfortable deploying it. I wouldn't mind seeing it packaged for Debian/Ubuntu.