Why is IP address shown as unknown on Component Health page
Under 'Superuser > Health' some components have an IP Address listed as unknown and 'Last Heartbeat' is Critical as shown below;
When a component identifies itself differently, possibly only for a brief time, then a new row is created. Then later, perhaps upon a restart, the component once again identifies itself with an IP Address and the proper (original) row is updated. We now have no association with the Unknown Row and since the component never updates again in that fashion it will eventually be displayed as critical.
The 'Unknown' rows may be removed by clicking on the gear icon and selecting 'Remove this entry'