public List<AlertDefinition> getAgentDefinitions() {
    if (null != m_agentDefinitions) {
      return m_agentDefinitions;
    }

    m_agentDefinitions = getDefinitions(RootComponent.AMBARI_AGENT);
    return m_agentDefinitions;
  }
Gets all of the {@link AlertDefinition}s that exist on the path for all
agent hosts.

@return the alerts with {@link RootComponent#AMBARI_AGENT} as the component
        and {@code AMBARI} as the service.
ambari-server/src/main/java/org/apache/ambari/server/metadata/AmbariServiceAlertDefinitions.java