Error: "Underlying system error: No valid hosts could be found due to Das state" occurs when attempting to create a VM-VM anti-affinity rule

Products

• VMware Cloud Director

Issue/Introduction

• Unable to create anti-affinity rules via the Cloud Director (VCD) Tenant portal.
• You are able to create the rule via vCenter.
• In the VCD UI the following error is visible:
  
  [ <requestid> ] Underlying system error: No valid hosts could be found due to Das state. vCenter Server task (moref: task ####) failed in vCenter Server '<vcentername>' (#########-####-####-####-########). - A component of the virtual machine is not accessible on the host.
  
  
• In the vCenter Server UI a "Create virtual machine" task for the drsShellVM is observed which states:
  
  A component of the virtual machine is not accessible on the host. No valid hosts could be found due to Das state

Environment

VMware Cloud Director 10.6.1.2

Cause

To validate the placement of VMs for an anti-affinity rule, VMware Cloud Director attempts to create a drsShellVm in vCenter.

This error occurs when the vSphere Cluster is configured with vSphere HA Admission Control using the Dedicated Failover Hosts option. If the drsShellVm is placed on a host designated as a failover host it will cause the anti-affinity rule creation to fail. Since dedicated failover hosts are reserved for emergency restarts and typically do not allow manual VM power-on operations, vCenter rejects the task, leading to the "Das state" (vSphere HA) error.

Resolution

To resolve this issue, temporary change the HA admission control configuration to allow VCD to complete the rule validation task.

1. Log in to the vCenter Server
2. Navigate to the vSphere cluster where the VMs are located
3. Go to the Configure tab and select vSphere Availability.
4. Click Edit button and navigate to the Admission Control tab.
5. Note the current Dedicated Failover Hosts settings.
6. Temporarily change the failover host to a different host in the cluster.
7. Return to Cloud Director and create the anti-affinity rule.
8. Once the rule is successfully created, revert the vSphere HA settings in vCenter to their original configuration.

Additional Information

Create a VM Anti-Affinity Rule in the VMware Cloud Director Tenant Portal
Dedicated Failover Hosts Admission Control