private void removeHostFromClusterTopology(long clusterId, String hostname) {
    ClusterTopology clusterTopology = topologyManager.getClusterTopology(clusterId);
    if(clusterTopology != null) {
      clusterTopology.removeHost(hostname);
    }
  }
Removes hostname from the stateful cluster topology
ambari-server/src/main/java/org/apache/ambari/server/controller/internal/HostResourceProvider.java