New resource pool not being consumed in VMware Cloud Director

Products

• VMware Cloud Director

Issue/Introduction

• An existing resource pool in a provider VDC is violating the configured headroom threshold for CPU or memory.
• An additional resource pool has been added to the VDC, but virtual machines are not being deployed to this as expected.
• There is more overall memory and CPU resources available on the original resource pool.
• In the file /opt/vmware/vcloud-director/logs/vcloud-container-debug.log, there are errors similar to the following for the new resource pool and, potentially, for the original pool:
  
  2026-02-25 18:13:21,710 | DEBUG    | Backend-activity-pool-18  | MaxMinHubRanker                | Not enough storage headroom for Hub: moref://########-####-####-####-############/ResourcePool#resgroup-### total capacity ##,###,###,### free capacity ##,###,### | requestId=########-####-####-####-############,request=POST https://####.####.###/api/vdc/########-####-####-####-############/action/composeVApp,requestTime=############,remoteAddress=###.###.###.###:#####,userAgent=... vcd=########-####-####-####-############,task=########-####-####-####-############ activity=(com.vmware.vcloud.backendbase.management.system.TaskActivity,urn:uuid:########-####-####-####-############) activity=(com.vmware.vcloud.vdc.impl.ComposeRecomposeVAppActivity,urn:uuid:########-####-####-####-############)
  
  
• There is sufficient storage on the storage policy and the red or yellow thresholds have not been violated in VMware Cloud Director.

Environment

VMware Cloud Director 10.6.x

Cause

VMware Cloud Director (VCD) has determined that the storage headroom on the new resource pool has been violated. This places the resource pool on a headroom breach list that also contains pools that have breached for CPU or memory. If there are no group or host affinity directives causing an item to be preferentially placed, all items on the breach list will be evaluated equally and the placement engine will prefer to place the item in the pool with the most available resources. Thus, if the original pool still has more overall resources, the placement engine will select that item.

There are currently known limitations in VCD that can cause the storage headroom calculation to more likely result in a violation state.

Resolution

If there is sufficient storage capacity associated with the resource pool, the storage headroom parameter can be reduced, as discussed in the following documentation, to prevent violation:

About the VMware Cloud Director Workload Placement Engine

Refer to the total capacity and free capacity values in the error to determine the percentage of free space being calculated by VCD.