In the general case, the ClusterClient fails to submit jobs to an HA cluster. The problem is the LazyActorSystemLoader which creates an ActorSystem, upon first call. The ActorSystem is created by reading the JobManager's address from the Configuration in order to find the connecting address via ConnectionUtils.findConnectingAddress. The address in the configuration is, however, only valid in the non-HA case. In the HA case, we have to obtain the leader's address from ZooKeeper. Therefore, if the address is not explicitly set in the flink-conf.yaml, then the ClusterClient might either fail with a RuntimeException if no address at all has been specified or it will use an invalid address and retrieve the wrong connecting address.