public void setRole(String role) {
    this.role = role;
  }
Sets the request and stage on this command. The {@code commandId} field is
automatically constructed from these as requestId-stageId.

@param requestId
         the ID of the execution request.
@param stageId
         the ID of the stage request.
ambari-server/src/main/java/org/apache/ambari/server/agent/ExecutionCommand.java