private void loadServiceConfigTypes() throws AmbariException {
    try {
      serviceConfigTypes = collectServiceConfigTypesMapping();
    } catch (AmbariException e) {
      LOG.error("Cannot load stack info:", e);
      throw e;
    }
    LOG.info("Service config types loaded: {}", serviceConfigTypes);
  }
A simple cache for looking up {@code cluster-env} properties for a cluster.
This map is changed whenever {{cluster-env}} is changed and we receive a
{@link ClusterConfigChangedEvent}.
ambari-server/src/main/java/org/apache/ambari/server/state/cluster/ClusterImpl.java