Adding a cluster in VCF fails with error "CLUSTER_NAME_ALREADY_ALLOCATED_FOR_DOMAIN"

Products

• VMware SDDC Manager / VCF Installer
• VMware Cloud Foundation

Issue/Introduction

• Adding a new cluster to an existing workload domain in VMware Cloud Foundation (VCF) fails during the validation phase.
• The SDDC Manager UI displays the following error: Failed to submit new add cluster configuration: Failed to validate cluster spec for [CLUSTER_NAME] with errors [CLUSTER_NAME_ALREADY_ALLOCATED_FOR_DOMAIN] : Cluster name '[CLUSTER_NAME]' is already allocated for domain with ID '[DOMAIN_ID]'.
• In /var/log/vmware/vcf/domainmanager/domainmanager.log in the sddc manager, the following entries are observed:

  ERROR [vcf_dm] [c.v.v.c.c.v1.ClusterController] ClusterCreationSpec validation failed with errors [CLUSTER_NAME_ALREADY_ALLOCATED_FOR_DOMAIN]
  ERROR [vcf_dm] [c.v.v.c.c.v1.ClusterController] Failed to create cluster
  com.vmware.evo.sddc.common.core.error.CompositeInvalidInputException: Failed to validate cluster spec for [CLUSTER_NAME] with errors [CLUSTER_NAME_ALREADY_ALLOCATED_FOR_DOMAIN]
   

Environment

• VMware Cloud Foundation 9.x

Cause

• This issue occurs due to a stale entry in the Domain Manager's in-memory cache. Even if a previous cluster creation attempt was cancelled or failed, the Domain Manager may still "reserve" the cluster name, preventing subsequent attempts using the same name.

Resolution

• To resolve this issue, you must restart the Domain Manager service to clear the stale cache.
• [!IMPORTANT] Ensure there are no active workflows (such as password rotations, host commissionings, or other domain operations) running in the Domain Manager before proceeding.
  
  1.Log in to the SDDC Manager appliance via SSH using the vcf user credentials.
  2. Switch to the root user:
  
  

  su -

  3. Restart the Domain Manager service by running the following command:

  systemctl restart domainmanager.service

  4. Retry the "Add Cluster" operation from the SDDC Manager UI.