We've grown enough to need high availability solution, so the first thing I've tried is Heartbeat. It turned out enough for now (although, I'll have to update a few init scripts), and I'll write a mini-howto on running Heartbeat inside OpenVZ container as soon as I have enough time for that.
For now, just one hint. If your node doesn't come up when it should, and /var/log/ha-log contains the following:
Setup problem: Couldn't find utility /bin/gawk
then it's most probably not really about gawk (it's very hard to find Linux system without gawk). It may also mean that you don't have which installed, while Heartbeat's scripts use it to find a real path to gawk. It's not that common, too, actually, but, for example, some OpenVZ templates do not include which package.
So, yum install which (or vzyum $VEID install which) brings you happiness.Top