how do you measure the number of connections? is that because some threads are not killed upon redeploy?
there’s been an improvement on resource cleanup front in 2.1.4 so you should probably upgrade (see https://www.couchbase.com/issues/browse/JVMCBC-201).
but note that RxJava itself is currently not very adapted to hot-redeploy and will “leak” threads (see this topic and the corresponding RxJava ongoing discussion in PR #3149).