This should be simple, but it bugs me nonetheless. I came across a practice question that asked whether the vCenter server is required to be part of a Windows domain. The "correct" answer is Yes. I'm not so sure. Per the ESXi Installable and vCenter Server Setup Guide, page 91:
"The system that you use for your vCenter Server installation must belong to a domain rather than a
workgroup. If assigned to a workgroup, the vCenter Server system is not able to discover all domains and
systems available on the network when using such features as vCenter Guided Consolidation Service."
How can it be a requirement, but in the next statement it states what wouldn't work? This tells me that it's preferred to be a Windows domain member, but not a requirement. Your thoughts?