public boolean validateAgentHostnames() {
    return Boolean.parseBoolean(getProperty(SRVR_AGENT_HOSTNAME_VALIDATE));
  }
Check to see if the hostname of the agent is to be validated as a proper hostname or not

@return true if agent hostnames should be checked as a valid hostnames; otherwise false
ambari-server/src/main/java/org/apache/ambari/server/configuration/Configuration.java