Let's say you want to shut down a CVM for maintenance, firmware upgrade or any other reason, and when you run "cvm_shutdown -P" you get this error:
"StandardError: Cannot connect to genesis to check node configuration status"
If you have an older version of AOS (5.5.x or 5.6.x) then the shutdown script on your CVM might need a small modification, you can contact Nutanix support and an engineer will edit the file on the spot, or you can upgrade the AOS to a newer version which has the fix.
If you have a newer version and you want to shutdown a node in the cluster, make sure that you follow the correct shutdown process depending on your hypervisor, here are the instructions for each: AHV, ESXi, hyper-v or Citrix.
You can also check out KB-3270 for the cvm_shutdown script.