Hello - I am playing around with Zeppelin in a mesos/docker setup and am using HAProxy/mesosDNS to connect to my instances.
For those who want a cliff notes on this, HAProxy takes apps started in marathon and routes them to appropriate host on the mesos cluster, the mesos-DNS allows me to have hosts connect directly to the instances running in Docker. One thing I've noticed (and this is an issue with the HAProxy stuff in general, not sure Zeppelin) is if the TCP connection running through HAProxy is long running with not a lot of activity, HAProxy will think the connection is dead and terminate it. This can be a pain for say long running queries with a Hive Thrift server. In Zeppelin, it appears that the problem manifests itself when there is no activity in a notebook, and the "Connected (with a green box)" in the Upper right changes to "Disconnected (with a red box)" Basically HAProxy closes the connection. To fix, I just refresh, and things work fine, but it's annoying to say the least. Would it be possibly to setup HTTP keep alives on these connections? I am not an expert on web servers being used in Zeppelin, but having an option to be able to send keep alives when the notebook is open ever X seconds if no other activity would solve this problem well. I know this may see minor, but there may be others using it in an environment with HAProxy or other similar setups, and if the effort is low on something like, it would be greatly appreciated.
