Error:"Cannot create External Network. Existing network backings in use or is an uplink" when creating an external network in VMware Cloud Director

Products

• VMware Cloud Director

Issue/Introduction

• VLAN port group associated with the network was deleted and recreated in vCenter
• Attempting to recreate the external network using same VLAN in VMware Cloud Director fails with the error
  
  Cannot create External Network. Existing network backings NETWORK_NAME VLAN ### (dvportgroup-####) in use or is an uplink. Possible solution would be to configure overlapping networks (i.e. if you wish to use the same VLAN ID)".
  
  
• Following entries are seen under /opt/vmware/vcloud-director/logs/networking.log:

DATE TIME  | DEBUG    | auto-pool-Monitor Service-13-thread-19 | CreateExternalRealNetworkActivity | [Activity Execution] Serializing Future: CLAIM_PORT_GROUP_FOR_EXTERNAL_REAL_NETWORK-> ActivityFutureTask [activityExecutionState=AbstractActivityExecutionState [activityName=com.vmware.vcloud.fabric.net.activities.network.externalrealnetwork.ClaimPortGroupForExternalRealNetworkActivity, clientURI=urn:uuid:########-####-####-########7d9a, entityURI=urn:uuid:########-####-####-########7239, currentPhase=com.vmware.vcloud.fabric.net.activities.network.externalrealnetwork.ClaimPortGroupForExternalRealNetworkActivity$VerifyReleasePortgroupsAndFailPhase, cancelRequested=false, parameters(size)=13], exception=
java.util.concurrent.ExecutionException: com.vmware.vcloud.api.presentation.service.EntityIsInUseException: 
Existing network backings NETWORK_NAME_VLAN-#### VLAN #### (dvportgroup-#######) in use or is an uplink.  
Possible solution would be to configure overlapping networks (i.e. if you wish to use the same VLAN ID)., partialFailure=false, partialFailureException=null, nullResult=false, result=null, canceled=false] - Handle: urn:uuid:fdc########-####-####-########cd64, Current Phase: CreateExternalRealNetworkActivity$ClaimPortGroupForExternalNetworkPhase |
  
  
• From the API response from browser developer tools when reproducing the error the following error is reported:
  {
    "minorErrorCode": "ENTITY_IS_IN_USE",
    "message": "[########-####-####-########] Existing network backings NETWORK_NAME (dvportgroup-xxxx) in use or is an uplink.  Possible solution would be to configure overlapping networks (i.e. if you wish to use the same VLAN ###).",
    "stackTrace": "com.vmware.vcloud.api.presentation.service.EntityIsInUseException: Existing network backings NETWORK_NAME VLAN ### (dvportgroup-####) in use or is an uplink.  Possible solution would be to configure overlapping networks (i.e. if you wish to use the same VLAN ###).\n\tat com.vmware.vcloud.fabric.net.activities.network.externalrealnetwork.ClaimPortGroupForExternalRealNetworkActivity$VerifyReleasePortgroupsAndFailPhase.execute(ClaimPortGroupForExternalRealNetworkActivity.java:178)\n\tat com.vmware.vcloud.fabric.net.activities.AbstractNetworkFabricActivity$AbstractBaseNetworkingActivityPhase.invoke(AbstractNetworkFabricActivity.java:101)\n\tat
  
  
• If we change the VLAN ID of the port group from vCenter, creation of external network using this port group is successful from VCD.

Environment

VMware Cloud Director 10.5.1

Cause

VLAN ID backed port group was deleted and recreated directly from vCenter leaving stale VLAN ID references in VCD database.

Resolution

Database modifications are required to remove VLAN ID references from Cloud Director. To resolve this issue, please open a Support Request with Broadcom Technical Support and note this Article ID (383104) in the problem description. For more information, see Creating and managing Broadcom support cases.