In our environment 1 Host stopped responding. You cannot reach it over vCenter, Host Client, SSH, DCUI. You cannot login to the ESXi but all VMs are still running. Bad news: you have to restart your host hard but you can shutdown the VM over the Guest system so no dirty shutdown ;).
First VMware Ticket => this happens sometimes restart host …
A few days later second host the same symptoms. After reopening the Ticket they found an internal knowledge-base article. The reason was the “Active Directory Service” of the ESXi. ESXi uses “Likewise” to authenticate again the Active Direcorty. In our case the Likewise cache ran out of memory and the management of the ESXi became unavailable.
So the resultion from VMware was extend the Likewise Cache…
Happend again :/ now we actived likewise logging and have to wait for the next crash
After a few VMware-Tickets now there is an offical knowledge base artikel with a workaround but at the moment no resolution: