Sounds like you are hitting undertow bug [UNDERTOW-635] mod_cluster incorrectly parses out route: strips everything after '.' in the route - JBoss Issue Tracker that causes sticky sessions to be broken, can you check that?
To be honest, I'm not sure how to reproduce the issue again.
I tried another time, I started servers 2 and 3 in domain mode, and this time I got the opposite problem.
The load balancer does never balance to the server 2, it always forward requests to server 3. It seems it consider the order in which they are declared in the handler:
<host name="host2" outbound-socket-binding="srv217" scheme="ajp" instance-id="myroute" path="/"/>
<host name="host1" outbound-socket-binding="srv216" scheme="ajp" instance-id="myroute" path="/"/>
Then I removed host2 from the handler, and I noticed host1 was not being accessed at all from the balancer.
This remote proxy feature is seeming a little unpredictable for me, if I manage to reproduce the original issue again, I'll answer this thread.
Ok, sorry, I thought you were talking about modcluster, now I see you are talking about static configuration.