@DB
  protected boolean applyLoadBalancerRules(List<LoadBalancerVO> lbs)
      throws ResourceUnavailableException {
    Transaction txn = Transaction.currentTxn();
    List<LoadBalancingRule> rules = new ArrayList<LoadBalancingRule>();
    for (LoadBalancerVO lb : lbs) {
      List<LbDestination> dstList = getExistingDestinations(lb.getId());

      LoadBalancingRule loadBalancing = new LoadBalancingRule(lb, dstList);
      rules.add(loadBalancing);
    }

    if (!_networkMgr.applyRules(rules, false)) {
      s_logger.debug("LB rules are not completely applied");
      return false;
    }

    for (LoadBalancerVO lb : lbs) {
      txn.start();
      if (lb.getState() == FirewallRule.State.Revoke) {
        _lbDao.remove(lb.getId());
        s_logger.warn("LB " + lb.getId() + " is successfully removed");
      } else if (lb.getState() == FirewallRule.State.Add) {
        lb.setState(FirewallRule.State.Active);
        s_logger.warn("LB rule " + lb.getId() + " state is set to Active");
        _lbDao.persist(lb);
      }

      // remove LB-Vm mappings that were state to revoke
      List<LoadBalancerVMMapVO> lbVmMaps = _lb2VmMapDao.listByLoadBalancerId(lb.getId(), true);
      List<Long> instanceIds = new ArrayList<Long>();

      for (LoadBalancerVMMapVO lbVmMap : lbVmMaps) {
        instanceIds.add(lbVmMap.getInstanceId());
      }

      if (!instanceIds.isEmpty()) {
        _lb2VmMapDao.remove(lb.getId(), instanceIds, null);
        s_logger.debug(
            "Load balancer rule id " + lb.getId() + " is removed for vms " + instanceIds);
      }

      if (_lb2VmMapDao.listByLoadBalancerId(lb.getId()).isEmpty()) {
        lb.setState(FirewallRule.State.Add);
        _lbDao.persist(lb);
        s_logger.debug(
            "LB rule "
                + lb.getId()
                + " state is set to Add as there are no more active LB-VM mappings");
      }

      txn.commit();
    }
    return true;
  }
  @Override
  public List<UserVmVO> listLoadBalancerInstances(ListLoadBalancerRuleInstancesCmd cmd)
      throws PermissionDeniedException {
    Account caller = UserContext.current().getCaller();
    Long loadBalancerId = cmd.getId();
    Boolean applied = cmd.isApplied();

    if (applied == null) {
      applied = Boolean.TRUE;
    }

    LoadBalancerVO loadBalancer = _lbDao.findById(loadBalancerId);
    if (loadBalancer == null) {
      return null;
    }

    _accountMgr.checkAccess(caller, null, loadBalancer);

    List<UserVmVO> loadBalancerInstances = new ArrayList<UserVmVO>();
    List<LoadBalancerVMMapVO> vmLoadBalancerMappings = null;

    vmLoadBalancerMappings = _lb2VmMapDao.listByLoadBalancerId(loadBalancerId);

    List<Long> appliedInstanceIdList = new ArrayList<Long>();
    if ((vmLoadBalancerMappings != null) && !vmLoadBalancerMappings.isEmpty()) {
      for (LoadBalancerVMMapVO vmLoadBalancerMapping : vmLoadBalancerMappings) {
        appliedInstanceIdList.add(vmLoadBalancerMapping.getInstanceId());
      }
    }

    IPAddressVO addr = _ipAddressDao.findById(loadBalancer.getSourceIpAddressId());
    List<UserVmVO> userVms =
        _vmDao.listVirtualNetworkInstancesByAcctAndZone(
            loadBalancer.getAccountId(), addr.getDataCenterId(), loadBalancer.getNetworkId());

    for (UserVmVO userVm : userVms) {
      // if the VM is destroyed, being expunged, in an error state, or in an unknown state, skip it
      switch (userVm.getState()) {
        case Destroyed:
        case Expunging:
        case Error:
        case Unknown:
          continue;
      }

      boolean isApplied = appliedInstanceIdList.contains(userVm.getId());
      if ((isApplied && applied) || (!isApplied && !applied)) {
        loadBalancerInstances.add(userVm);
      }
    }

    return loadBalancerInstances;
  }
  @Override
  public List<LbDestination> getExistingDestinations(long lbId) {
    List<LbDestination> dstList = new ArrayList<LbDestination>();
    List<LoadBalancerVMMapVO> lbVmMaps = _lb2VmMapDao.listByLoadBalancerId(lbId);
    LoadBalancerVO lb = _lbDao.findById(lbId);

    String dstIp = null;
    for (LoadBalancerVMMapVO lbVmMap : lbVmMaps) {
      UserVm vm = _vmDao.findById(lbVmMap.getInstanceId());
      Nic nic = _nicDao.findByInstanceIdAndNetworkIdIncludingRemoved(lb.getNetworkId(), vm.getId());
      dstIp = nic.getIp4Address();
      LbDestination lbDst =
          new LbDestination(
              lb.getDefaultPortStart(), lb.getDefaultPortEnd(), dstIp, lbVmMap.isRevoke());
      dstList.add(lbDst);
    }
    return dstList;
  }
  @Override
  public boolean removeVmFromLoadBalancers(long instanceId) {
    boolean success = true;
    List<LoadBalancerVMMapVO> maps = _lb2VmMapDao.listByInstanceId(instanceId);
    if (maps == null || maps.isEmpty()) {
      return true;
    }

    Map<Long, List<Long>> lbsToReconfigure = new HashMap<Long, List<Long>>();

    // first set all existing lb mappings with Revoke state
    for (LoadBalancerVMMapVO map : maps) {
      long lbId = map.getLoadBalancerId();
      List<Long> instances = lbsToReconfigure.get(lbId);
      if (instances == null) {
        instances = new ArrayList<Long>();
      }
      instances.add(map.getInstanceId());
      lbsToReconfigure.put(lbId, instances);

      map.setRevoke(true);
      _lb2VmMapDao.persist(map);
      s_logger.debug(
          "Set load balancer rule for revoke: rule id "
              + map.getLoadBalancerId()
              + ", vmId "
              + instanceId);
    }

    // Reapply all lbs that had the vm assigned
    if (lbsToReconfigure != null) {
      for (Map.Entry<Long, List<Long>> lb : lbsToReconfigure.entrySet()) {
        if (!removeFromLoadBalancerInternal(lb.getKey(), lb.getValue())) {
          success = false;
        }
      }
    }
    return success;
  }
  @DB
  public boolean deleteLoadBalancerRule(
      long loadBalancerId, boolean apply, Account caller, long callerUserId) {
    LoadBalancerVO lb = _lbDao.findById(loadBalancerId);
    Transaction txn = Transaction.currentTxn();
    boolean generateUsageEvent = false;
    boolean success = true;

    txn.start();
    if (lb.getState() == FirewallRule.State.Staged) {
      if (s_logger.isDebugEnabled()) {
        s_logger.debug("Found a rule that is still in stage state so just removing it: " + lb);
      }
      generateUsageEvent = true;
    } else if (lb.getState() == FirewallRule.State.Add
        || lb.getState() == FirewallRule.State.Active) {
      lb.setState(FirewallRule.State.Revoke);
      _lbDao.persist(lb);
      generateUsageEvent = true;
    }

    List<LoadBalancerVMMapVO> maps = _lb2VmMapDao.listByLoadBalancerId(loadBalancerId);
    if (maps != null) {
      for (LoadBalancerVMMapVO map : maps) {
        map.setRevoke(true);
        _lb2VmMapDao.persist(map);
        s_logger.debug(
            "Set load balancer rule for revoke: rule id "
                + loadBalancerId
                + ", vmId "
                + map.getInstanceId());
      }
    }

    if (generateUsageEvent) {
      // Generate usage event right after all rules were marked for revoke
      UsageEventVO usageEvent =
          new UsageEventVO(
              EventTypes.EVENT_LOAD_BALANCER_DELETE, lb.getAccountId(), 0, lb.getId(), null);
      _usageEventDao.persist(usageEvent);
    }

    txn.commit();

    if (apply) {
      try {
        if (!applyLoadBalancerConfig(loadBalancerId)) {
          s_logger.warn("Unable to apply the load balancer config");
          return false;
        }
      } catch (ResourceUnavailableException e) {
        s_logger.warn(
            "Unable to apply the load balancer config because resource is unavaliable.", e);
        return false;
      }
    }

    FirewallRuleVO relatedRule = _firewallDao.findByRelatedId(lb.getId());
    if (relatedRule != null) {
      s_logger.warn(
          "Unable to remove firewall rule id="
              + lb.getId()
              + " as it has related firewall rule id="
              + relatedRule.getId()
              + "; leaving it in Revoke state");
      success = false;
    } else {
      _firewallDao.remove(lb.getId());
    }

    _elbMgr.handleDeleteLoadBalancerRule(lb, callerUserId, caller);
    if (success) {
      s_logger.debug("Load balancer with id " + lb.getId() + " is removed successfully");
    }

    return success;
  }
  @Override
  @DB
  @ActionEvent(
      eventType = EventTypes.EVENT_ASSIGN_TO_LOAD_BALANCER_RULE,
      eventDescription = "assigning to load balancer",
      async = true)
  public boolean assignToLoadBalancer(long loadBalancerId, List<Long> instanceIds) {
    UserContext ctx = UserContext.current();
    Account caller = ctx.getCaller();

    LoadBalancerVO loadBalancer = _lbDao.findById(loadBalancerId);
    if (loadBalancer == null) {
      throw new InvalidParameterValueException(
          "Failed to assign to load balancer "
              + loadBalancerId
              + ", the load balancer was not found.");
    }

    List<LoadBalancerVMMapVO> mappedInstances =
        _lb2VmMapDao.listByLoadBalancerId(loadBalancerId, false);
    Set<Long> mappedInstanceIds = new HashSet<Long>();
    for (LoadBalancerVMMapVO mappedInstance : mappedInstances) {
      mappedInstanceIds.add(Long.valueOf(mappedInstance.getInstanceId()));
    }

    List<UserVm> vmsToAdd = new ArrayList<UserVm>();

    for (Long instanceId : instanceIds) {
      if (mappedInstanceIds.contains(instanceId)) {
        throw new InvalidParameterValueException(
            "VM " + instanceId + " is already mapped to load balancer.");
      }

      UserVm vm = _vmDao.findById(instanceId);
      if (vm == null || vm.getState() == State.Destroyed || vm.getState() == State.Expunging) {
        throw new InvalidParameterValueException("Invalid instance id: " + instanceId);
      }

      _rulesMgr.checkRuleAndUserVm(loadBalancer, vm, caller);

      if (vm.getAccountId() != loadBalancer.getAccountId()) {
        throw new PermissionDeniedException(
            "Cannot add virtual machines that do not belong to the same owner.");
      }

      // Let's check to make sure the vm has a nic in the same network as the load balancing rule.
      List<? extends Nic> nics = _networkMgr.getNics(vm.getId());
      Nic nicInSameNetwork = null;
      for (Nic nic : nics) {
        if (nic.getNetworkId() == loadBalancer.getNetworkId()) {
          nicInSameNetwork = nic;
          break;
        }
      }

      if (nicInSameNetwork == null) {
        throw new InvalidParameterValueException(
            "VM " + instanceId + " cannot be added because it doesn't belong in the same network.");
      }

      if (s_logger.isDebugEnabled()) {
        s_logger.debug("Adding " + vm + " to the load balancer pool");
      }
      vmsToAdd.add(vm);
    }

    Transaction txn = Transaction.currentTxn();
    txn.start();

    for (UserVm vm : vmsToAdd) {
      LoadBalancerVMMapVO map = new LoadBalancerVMMapVO(loadBalancer.getId(), vm.getId(), false);
      map = _lb2VmMapDao.persist(map);
    }
    txn.commit();

    try {
      loadBalancer.setState(FirewallRule.State.Add);
      _lbDao.persist(loadBalancer);
      applyLoadBalancerConfig(loadBalancerId);
    } catch (ResourceUnavailableException e) {
      s_logger.warn("Unable to apply the load balancer config because resource is unavaliable.", e);
      return false;
    }

    return true;
  }