An update to close: it's a vmware issue: * new centos 5 creations exhibit the same behavior * a few months ago, we migrated from an esx 4.0 cluster to a new esx 4.1 cluster * we've just recently started using a new centos 6 template; the centos 6 system that's working was created before the migration * a fresh install on esxi 4.0.0 worked fine; when the vm was restarted on the new cluster, it exhibited the same failure. I'm hoping to get an esx 4.0 instance running to I can try the same test, as it seems that esx 4.0 vms will migrate properly and work. Failing that, we can clone the working centos 6 system for now until we can work with vmware to figure out what's going on...