Over the years, Nutanix has made several changes in the way it handles node hostnames. Thankfully, as of 5.20 a simplified command line tool was added to change AHV hostnames.

nutanix@CVM:~$ change_ahv_hostname --host_ip=10.10.10.10 --host_name=AHV-HOSTNAME

The hostname must follow naming conventions:

• The maximum length is 64 characters.
• Allowed characters are uppercase and lowercase letters (A-Z and a-z), decimal digits (0-9), dots (.), and hyphens (-).
• The hostname must start and end with a number or letter.

For more information, check out the AHV Administration Guide on the Nutanix Portal.