I'm running VMware vSphere 4 Essentials on three almost identically configured hosts with a mix of guests including Windows 2003 and 2008 as well as CentOS 5 and 6.
Recently I installed Update 3 on one of the hosts. The updated host runs Windows and CentOS 5 (kernel 2.6.18-308.13.1.el5 i686) VMs fine, but two CentOS 6 VMs (kernel 2.6.32-279.5.2.el6.x86_64) I tried refuse to come up. They display the GRUB menu just fine, but the kernel panics immediately with "early exception 0d". After moving the VM back to the host without update 3 it comes up fine again.
Any ideas how to fix or even start debugging this?
Btw, all my CentOS 6 VMs are 64 bit. Windows and CentOS 5 VMs come in both 32 and 64 bit flavours. Both 32 and 64 bit Windows VMs run fine on the updated host. So far I haven't tried a 64 bit CentOS 5 VM.