Just noticed the new errors HA produces at the console when a host is isolated in ESX 3.5:
Node isolated from network. Either repair network or override agent startup using option -noiso
And when the host returns from isolation:
Node no longer isolated, will restart
This makes troubleshooting a lot easier! Thanks VMware 
vSphere 4.0 Quick Start Guide
hi, how to use the -noiso option ??
that’s a great question, and something I never managed to find out. I will have a look again if I can find the time later today.