When a TAS application is queried during an upgrade or any other event where cells are evacuated, the CF gorouter responds with status code 499, even if all instances for a given application are running and there is no network connectivity issue between the goRouter and Diego Cells.
VMware NSX-T Data Center 3.x
During cell evacuation, application instances are supposed to be available until they shutdown or are destroyed by the rep job. Until this happens, the gorouter entry for a given instance is still active, and requests can be routed to it.
However. with NSX-T one of the following might happen:
This issue is resolved in NCP 3.0.2.5 and NCP 3.1.2.4
Workaround:
There is no workaround available.
Increasing the number of instances for an application and reducing max_in_flight to 1 might mitigate the issue, but it can still occur.