Earlier this summer I worked on a client's servers. They had three VMWare ESXi 6.5 hosts running vSphere Essentials Plus. The high level tasks were to migrate vCenter Server to 7.x, replace two ESXi hosts with two hosts running ESXi 7.x, and lastly upgrade the last host to ESXi 7.x. One of the new features of ESXi 7.x that caused me a lot of grief, mostly due to unfamiliarity, was vSphere Cluster Services. My specific issues were vCenter Server deployed three guest OSes, one to each ESXi host. When I tried to put a host into maintenance mode to patch it or remove one of the old ESXi hosts I couldn't because it had a vCLS guest OS. When I tried to vMotion it to another ESXi host in vCenter Server I got an error or warning to the effect of "just leave it alone, we manage that guest OS for you." But I couldn't go into maintenance mode or remove the host with that guest OS present! I ended up going into retreat mode (https://4sysops.com/archives/vmware-vcenter-server-70-update-2-cluster-service-vcls-and-retreat-mode...) a couple of times just to get rid of those guest OSes so I could perform my tasks.
My questions are:
1. In my observation most of the clients are running vSphere Essentials not Essentials Plus. Most have just one ESXi host though some will have two or three managed by vCenter Server. This article ( https://kb.vmware.com/s/article/80472 ) says "This feature ensures cluster services such as vSphere DRS and vSphere HA are all available to maintain the resources and health of the workloads running in the clusters independent of the vCenter Server instance availability." It doesn't appear those features are even available in vSphere Essentials ( https://www.mustbegeek.com/understanding-vmware-vsphere-7-editions-and-features/ ). Is this something I won't have to worry about as they won't be present either due to there being just one host or it not being included in the license?
2. Can you either provide some insight or point me to an article that details how to manage vCLS guest OSes? I tried doing some web searches but haven't found a good article. How do you manage vCLS guest OSes when you need to add and remove hosts from your environment or update ESXi on an existing host?
Matthew
