public Map<Long, AlertDefinition> findByServiceMaster(long clusterId, String... serviceName) {
    return mapById(coerce(m_definitionDao.findByServiceMaster(clusterId, Sets.newHashSet(serviceName))));
  }
Gets the alert definitions for the specified host. This will include the
following types of alert definitions:
<ul>
<li>Service/Component alerts</li>
<li>Service alerts where the host is a MASTER</li>
<li>Host alerts that are not bound to a service</li>
</ul>

@param clusterName
         the cluster name (not {@code null}).
@param hostName
         the host name (not {@code null}).
@return the alert definitions for the host, or an empty set (never
        {@code null}).
ambari-server/src/main/java/org/apache/ambari/server/state/alert/AlertDefinitionHash.java