@Override
      public void onReplicaAddedOrRemoved(List<ReplicaId> addedReplicas, List<ReplicaId> removedReplicas) {
        removedReplicasFromListener.addAll(removedReplicas);
      }
Test removing instances from cluster dynamically
ambry-clustermap/src/test/java/com/github/ambry/clustermap/ClusterChangeHandlerTest.java