How It Started
I screwed up a vCenter instance. Actually it is pretty easy to screw up the state-of-the-art hypervisor controller from its beautifully designed web UI, using the appealing buttons that always have been there. The process only requires 2 simple steps:
So you have a handful of brand new ESXi servers, and want VMs to automagically move here and there based on host availability and resource usage; vCenter have you covered with the DRS and HA but obviously you need to put all the hosts into a cluster for these thing to work. What you might not know is that there are 3 ways of creating a cluster which differs in certain things, and you will regret it if you choose the wrong one. Trust me, I learned it the hard way.
Note: we are using ESXi 7.0 and vCenter 7.0 here.