title: Hazelcast in multinode docker environments with TCPIP
body: <p>I am currently struggling with the following problem:</p>
  
  <p>I have a Java EE application that shall be able to run in a cluster (it actually does). For the data exchange between the nodes I use Hazelcast 3.3.3.
  Since our customers are afraid of UDP we use TCP.
  So I configure 3 hazelcast parameters per node:
  The network interface to use, the port and the members of the cluster.
  In real life (not a docker environment) everything works.
  Now I want to put my Java EE servers into docker containers (one per node) and also link them via Hazelcast.</p>
  
  <p>What I did was:</p>
  
  <p>On the host machine running the docker containers I created several virtual network interfaces (172.21.0.X).
  for each docker container I gave network mappings like -p 172.21.0.X:5190:5190 (5190 is the port I use for Hazelcast)</p>
  
  <p>In my Java EE application within the container I configured hazelcast to listen to interface 172.21.0.X, port 5190 members 172.21.0.X:5190,......
  The problem now is: docker will assign an internal IP number to each cointainer. In advance I cannot be sure which IP number docker will assign.
  It definitly is not the IP I would like to use (172.21.0.X).
  Hazelcast starts up and tells me: no matching interface found. Of course not.
  Hazelcast will check the IP interfaces of the docker container which is something like 172.4.XX. This does not fit to the config I gave to hazelcast (use 172.21.X.X).</p>
  
  <p>So far it seems not to be possible to specify the internal IP number of a docker container. I could query it from a running container, but that is too late since I need to do the configuration of my Java EE server BEFORE I start the container.</p>
  
  <p>Any hints on that? Is it possible to get the Hazelcast running with TCPIP?</p>