However, if you wanted to script it, its really just two commands. Try this via SSH into a single CVM, you definitely do NOT need to go into all CVM's to do this (note, cluster stop is needed to stop cluster services gracefully first, don't shutdown without doing that if you can)
allssh 'nohup sleep 20 && cvm_shutdown -P'
Give that a try.
Jon Kohler | Principal Architect, Nutanix | Nutanix NPX #003, VCDX #116 | @JonKohler Please Kudos if useful!