Generic exception and HTTP 503 errors when using PowerVM Novalink

So recently I encountered an issue between communications on Novalink and the VIOS it managed. After VIOS being updated to VIOS 2.2.6.51 we noticed a few errors when we ran pvmctl vios list as well as pvmctl sea list. Both commands returned errors which were obscure.

[padmin@novalink ~]$ pvmctl vios list
HTTP error 503 for method GET on path /rest/api/uom/VirtualIOServer: Service Unavailable
[padmin@novalink ~]$ pvmctl sea list
VIOS0005 VIOS_LICENSE: Generic exception occurred in fetching license status for vios vio01 with ID 1 in CEC <REMOVED>

Looking through neutron logs on the Novalink partition, you could see that the neutron agent was crashing when attempting to communicate with the pvm-rest service. The pvm-rest service was running but failing to return any data for vio01.

A quick login to vio01 showed that the vio_daemon process was consuming 17% of the CPU on the system, which is atypical behaviour for the daemon. After a bit of investigating I noticed that /etc/hosts was missing an entry on this VIO server for its hostname, after adding this in the CPU utilization immediately returned to normal. This also resolved the communication issues with Novalink.