Error "Agent with ID already exists" when registering Usage Meter in VCF Business console

Products

• VMware Usage Meter

Issue/Introduction

• Attempting to register Usage Meter to a site on VCF Business console Register the VCF Usage Meter Appliance in the VCF Business Services Console fails with error
  "Failed to register this Usage Meter : Agent with ID xxxxxxxx already exists".
  
• The usage meter instance is not listed in VCF Business console : Site view > Usage Management > Usage meters {despite enabling the toggle for "Include unregistered Usage Meters"} 

Environment

• VCF Usage Meter 9.x

Cause

• The UM with the reported UUID is / previously was registered to another Site. 

Resolution

• To resolve the issue, follow either of the below options:
  1. Move the UM instance across tenants:
     1. Move the UM across tenants using UI:
        
        • Refer steps to move UM between tenants as below:
          https://techdocs.broadcom.com/us/en/vmware-cis/vcf/business-services/home/vcf-usage-meter-management/move-vcf-usage-meter-appliances-between-tenants.html
     2. Move the UM to the new tenant using API:
        
        • If the UM has no access token in the source tenant (unregistration is not mandatory) we can move the UM to a new tenant using the API. In the context of the 'DestinationTenant' tenant call 
          

          curl -X PATCH https://eapi.broadcom.com/vcf/ums/api/v2/<DestinationTenantID>/agents -H "Authorization: Bearer $TOKEN" -d '[{"agentId":"<agentId1>"},{"agentId":"<agentId2>",...,{"agentId":"<agentId10>"}}]'

        • In our case only one agent instance would be passed. 
        • Note:
          • We can call this API with up to 10 agents at a time. If the UMs are not unregistered in the response will contain new access tokens for the new tenant.
          • Else if we move unregistered UMs then they will remain in that same state in the new tenant. If we wish to use them we would have to re-register them in the new tenant and get access tokens to activate them.
        • Sample output:
          

          [
            {
              "agentId": "<agentID1>",
              "accessToken": <accessToken_for_agent1>"
            },{
              "agentId": "<agentID2>",
              "accessToken": "<accessToken_for_agent2>"
            },
            ...
            {
              "agentId": "<agentID10>",
              "accessToken": "<accessToken_for_agent10>"
            }
          ]

  2. Deploy and register a new UM instance to the new tenant:
     • Depending on the number of UMs and the size of the inventory being metered deploying a new UM might be the quickest approach.
     • https://techdocs.broadcom.com/us/en/vmware-cis/vcf/usage-meter/9-0/vcf-usage-meter-deployment-and-administration-guide.html