Couchbase Container's non-default port: Unusual behavior

[pratmeht]

We are observing unusual behavior related to Docker Container’s ports. Wanted to check if anyone has any knowledge about this:

Couchbase default ports:
 Web: 8091
 CBQ (Query Utility): 8093 and 8091

Assume we have 2 Couchbase containers on a host X named Cont1 and Cont2. Following are the Host:Container port mappings:
Cont1 -p 8091-8096:8091-8096 -p 11210-11211:11210-11211 [ Default ports ]
Cont2 -p 7091-7096:8091-8096 -p 17210-17211:11210-11211 [ Web port 7091 and CBQ ports 7093 and 7091 ]

Cont1 can be accessed via web on 8091 and via CBQ on 8091 and 8093 ports – Expected/Normal behaviour
Cont2 can be accessed via web on 7091 and via CBQ on 7093 port only, but if we use port 7091 then we get connected to Cont1 – Unexpected/Abnormal behaviour.

To test further, out of 2 containers if we stopped Cont1 (default host ports’ container), then usage of port 7091 with CBQ fails to connect to either of the containers!

We are unable to understand whether this is a bug or some port mapping issue? Any kind of explanation/logic would be helpful.