public Map<String, Map<String, String>> getEffectiveConfigProperties(String clusterName, String hostName) throws AmbariException {
    Cluster cluster = clusters.getCluster(clusterName);
    return getEffectiveConfigProperties(cluster, getEffectiveDesiredTags(cluster, hostName));
  }
Get all config properties for a cluster given a set of configType to
versionTags map. This helper method merges all the override tags with a
the properties from parent cluster config properties

@param cluster
@param desiredTags
@return {type : {key, value}}
ambari-server/src/main/java/org/apache/ambari/server/state/ConfigHelper.java