VM/Host affinity rules not enabling or functioning in vCenter

Products

• VMware vCenter Server

Issue/Introduction

VM/Host affinity rules fail to enable or do not trigger any migration actions. 

Additional observations include:

• Powered-on VMs do not move to satisfy the rule.
• Powered-off VMs are ignored by the placement engine.
• No errors are generated, but the rule remains ineffective.

Environment

• VMware vCenter Server 8.x
• vSphere Distributed Resource Scheduler (DRS)
• ESXi Cluster

Cause

• DRS is not  set to fully automated
• Even Distribution of VMs is not enforced to "MUST" in DRS settings
• Rule enforcement is set to a preferential "Should" (Soft) state rather than a mandatory "Must" (Hard) state.

Resolution

To ensure VM/Host affinity rules are enabled and functioning, verify the cluster configuration:

1. Ensure DRS is set to fully automated mode 
2. Navigate to DRS Settings and ensure the rule enforcement level is set to Must.
3. Verify that the VM group and Host group do not contain null or invalid entries.
4. For powered-off VMs, note that DRS placement occurs during a power-on event or a manual migration task.
5. Ensure no conflicting rules exist that prevent the desired placement.

      

 

Additional Information

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