After deploying a second UMP node to a robot attached to a secondary hub, the wasp probe starts up fine but the portal does not come up with an error that it cannot find mpse on the local hub.
The customer in this case followed our published documentation about setting up a secondary UMP node, found under this address:
If you study the guide you realize that it does not mention anything about the mpse probe being a requirement. The manual assumes that you are deploying the wasp probe to a robot attached to the same hub as the primary (first) UMP node and therefore the mpse probe would already be running on that hub after you run the UMP installer on the primary hub.
UIM 8.1 onwards
In the portal log you will see the following error after deploying the wasp probe (there will be no usable error in the wasp.log):
ERROR [MainServlet:1207] com.liferay.portal.kernel.events.ActionException: (4) not found, Received status (4) on response (for sendRcv) for cmd = 'nametoip' name = '/DOMAIN/HUBNAME/SECONDARYHUB/mpse'
com.liferay.portal.kernel.events.ActionException: (4) not found, Received status (4) on response (for sendRcv) for cmd = 'nametoip' name = '/DOMAIN/HUBNAME/SECONDARYHUB/mpse'
Even if you add the address of the mpse probe on the primary hub in the wasp raw configure under UMP_COMMON, the wasp will still look for the probe on the hub the robot is registered to and ignore this setting.
To resolve this issue you need to deploy the same version of the MPSE probe to the secondary hub as you have running on the primary hub. Once you have done this, restart the wasp probe and the portal will start up fine and you can logon to the secondary UMP node.