@Override
  public boolean prepareCreateTemplate(Long pxeServerId, UserVm vm, String templateUrl) {
    List<NicVO> nics = _nicDao.listByVmId(vm.getId());
    if (nics.size() != 1) {
      throw new CloudRuntimeException("Wrong nic number " + nics.size() + " of vm " + vm.getId());
    }

    /* use last host id when VM stopped */
    Long hostId = (vm.getHostId() == null ? vm.getLastHostId() : vm.getHostId());
    HostVO host = _hostDao.findById(hostId);
    DataCenterVO dc = _dcDao.findById(host.getDataCenterId());
    NicVO nic = nics.get(0);
    String mask = nic.getNetmask();
    String mac = nic.getMacAddress();
    String ip = nic.getIp4Address();
    String gateway = nic.getGateway();
    String dns = dc.getDns1();
    if (dns == null) {
      dns = dc.getDns2();
    }

    try {
      prepareCreateTemplateCommand cmd =
          new prepareCreateTemplateCommand(ip, mac, mask, gateway, dns, templateUrl);
      Answer ans = _agentMgr.send(pxeServerId, cmd);
      return ans.getResult();
    } catch (Exception e) {
      s_logger.debug("Prepare for creating baremetal template failed", e);
      return false;
    }
  }
  @DB
  public void work() {
    if (s_logger.isTraceEnabled()) {
      s_logger.trace("Checking the database");
    }
    final SecurityGroupWorkVO work = _workDao.take(_serverId);
    if (work == null) {
      if (s_logger.isTraceEnabled()) {
        s_logger.trace("Security Group work: no work found");
      }
      return;
    }
    Long userVmId = work.getInstanceId();
    if (work.getStep() == Step.Done) {
      if (s_logger.isDebugEnabled()) {
        s_logger.debug(
            "Security Group work: found a job in done state, rescheduling for vm: " + userVmId);
      }
      ArrayList<Long> affectedVms = new ArrayList<Long>();
      affectedVms.add(userVmId);
      scheduleRulesetUpdateToHosts(affectedVms, false, _timeBetweenCleanups * 1000l);
      return;
    }
    UserVm vm = null;
    Long seqnum = null;
    s_logger.debug("Working on " + work);
    final Transaction txn = Transaction.currentTxn();
    txn.start();
    boolean locked = false;
    try {
      vm = _userVMDao.acquireInLockTable(work.getInstanceId());
      if (vm == null) {
        vm = _userVMDao.findById(work.getInstanceId());
        if (vm == null) {
          s_logger.info("VM " + work.getInstanceId() + " is removed");
          locked = true;
          return;
        }
        s_logger.warn("Unable to acquire lock on vm id=" + userVmId);
        return;
      }
      locked = true;
      Long agentId = null;
      VmRulesetLogVO log = _rulesetLogDao.findByVmId(userVmId);
      if (log == null) {
        s_logger.warn("Cannot find log record for vm id=" + userVmId);
        return;
      }
      seqnum = log.getLogsequence();

      if (vm != null && vm.getState() == State.Running) {
        Map<PortAndProto, Set<String>> rules = generateRulesForVM(userVmId);
        agentId = vm.getHostId();
        if (agentId != null) {
          SecurityIngressRulesCmd cmd =
              generateRulesetCmd(
                  vm.getInstanceName(),
                  vm.getPrivateIpAddress(),
                  vm.getPrivateMacAddress(),
                  vm.getId(),
                  generateRulesetSignature(rules),
                  seqnum,
                  rules);
          Commands cmds = new Commands(cmd);
          try {
            _agentMgr.send(agentId, cmds, _answerListener);
          } catch (AgentUnavailableException e) {
            s_logger.debug(
                "Unable to send updates for vm: " + userVmId + "(agentid=" + agentId + ")");
            _workDao.updateStep(work.getInstanceId(), seqnum, Step.Done);
          }
        }
      }
    } finally {
      if (locked) {
        _userVMDao.releaseFromLockTable(userVmId);
        _workDao.updateStep(work.getId(), Step.Done);
      }
      txn.commit();
    }
  }