NGT Upgrade messages - what do they mean

If the UI is showing a VM cannot be upgraded, i.e. “NGT can only be upgraded on 0/1 VMs which have the available upgrade of NGT.” this normally indicates a communication error, or a version requirement not met.

Other issues, such as no empty CDROM drive, winrm “Basic” auth not enabled, no local admin account, or otherwise not meeting the configuration requirements in the doc linked above could result in a failed attempt, but those should not cause this message.

Essentially if you are seeing “NGT can only be upgraded on 0/1 VMs which have the available upgrade of NGT.” then the Prism service was not able to confirm supported versions and that NGT on the VM is currently communicating to Prism Element.

The next step would be to check NGT status from NCLI with the command:
nutanix@CVM:~$ ncli ngt list 
or 

nutanix@CVM:~$ ncli ngt list vm-name=MyVMName

In the output, look for this last line:
Communication Link Active : false 

Seeing “false” indicates the current Nutanix Guest Agent service on the VM is either not running or not able to communicate to Prism. If NGT was installed but the communication link isn’t active, you can find more details about the communication failure in C:\Program Files\Nutanix\Logs\ on a Windows machine, or /usr/local/nutanix/ngt/logs on a Linux machine.

If you need to root cause this communication failure, I’d recommend to open a support ticket. If you just want to get it working, in most cases, if network communication from the VM to Prism Element is working, your recourse at this point would be to reinstall NGT for those VMs this time. We cannot automatically update NGT if the link is already broken. 

1. Ensure the virtual CDROM is empty (previously mounted NGT CDROM could be problematic)
2. From Prism select the VM, click Manage Guest Tools, confirm Enable Nutanix Guest Tools, then Mount Nutanix Guest Tools.
3. Launch the VM console, or otherwise connect to the VM, then run the installer from the CDROM. This updates the VM’s NGT installation with the current Prism IP address, unique VM identification, and keys for secure access. Connecting to Prism is part of the install process, so you should see an error if there’s some other issue.

After this process completes, you should be able to confirm from NCLI using the previous command, and see that the communication link is working. After a subsequent AOS upgrade, you should see the batch-upgrade process through Prism Central working.

Thank you for the pointers, it looks like 6 out of 60 VMs did not get the upgrade, mainly due to the VM CDrom being occupied by another ISO image.  I have mounted manually and installed and all is well in my Nutanix world.