Joining ESXi host in eval mode to a licensed vSphere cluster

[dbbar]

Can anyone clarify if it's possible to add an ESXi host running in evaluation mode into a fully licensed vSphere cluster? We are replacing one of our current ESXi host servers, and we would like to connect the new host server first, configure it, migrate over what we need, move the existing license over, then spin down the old server. Documentation seems to imply that this is possible, but our vCenter throws out the error "License not available to perform this operation" when trying to join the new host server. We have a fully licensed VCSA (v6.5) running vCenter Server Standard, it recognizes the new host server (running ESXi 6.5U3) during the Add Host process, we have the option to select Evaluation License on the Assign License step, it can see the correct number of evaluation days remaining on the host, but it displays the licensing error and deletes the new host from the inventory after completing the setup. The new host is definitely running in 60-day Evaluation Mode, not Free Mode, it's running the base 00000-00000-00000-00000-00000 key and no other license has been applied to it yet.

[vXav]

Can you check that the host's time configuration is right? Make sure it can reach its ntp server or set it in the bios.

[dbbar]

I thought that too, time drift seemed to be a common cause in other similar topics that I could find. The dates & times match on the host server running the VCSA and the new ESXi host, and their NTP services are syncing with external time servers. Disabling vMotion on the new server's management vmkernel adapter was another fix in some cases. Management is the only service currently running on the new server's default/only vmk port.

We inherited this vSphere deployment from a previous tech support service, and part of me thinks it might be an issue on the VCSA. When adding the new host fails, the Task Console in vCenter logs a status error: License file download from (new host's IP addr) to vCenter Server failed due to exception: vmodl.RuntimeFault. The Event Console logs the error: Failed to download license information from the host (new host's IP addr) due to com.vmware.license.DLFDownloadFailedEvent.DLFDownloadFailedReason.error.label

That looks like a technical or configuration fault error, but I could be mis-reading them if they're just a "normal" generic error triggered by the evaluation license on the new host.