Error: "Cannot find backing for network" when changing a VM networks in VMware Cloud Director

Products

• VMware Cloud Director

Issue/Introduction

When attempting to either edit a VM or change the network for a VM, the below error is received:

[ ##################### ] Cannot find backing for network <Network Name>
com.vmware.vcloud.api.presentation.service.InternalServerErrorException: Cannot find backing for network <Network Name>
    at com.vmware.vcloud.dl.net.networkedvm.impl.DefaultNetworkedVmManager.getAttachedNetworkVALRef(DefaultNetworkedVmManager.java:429)
    at com.vmware.vcloud.dl.net.networkedvm.impl.DefaultNetworkedVmManager.createDeployedNicSpec(DefaultNetworkedVmManager.java:376)
    at com.vmware.vcloud.dl.net.networkedvm.impl.DefaultNetworkedVmManager.prepareDeployedNicConfigSpec(DefaultNetworkedVmManager.java:328)
    at com.vmware.ssdc.backend.services.impl.RelocateVmActivity$RelocateVmAcrossRpAndDsPhase.invoke(RelocateVmActivity.java:863)
    at com.vmware.vcloud.activity.executors.ActivityRunner.runPhase(ActivityRunner.java:175)
    at com.vmware.vcloud.activity.executors.ActivityRunner.run(ActivityRunner.java:112)
    at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
    at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
    at java.base/java.lang.Thread.run(Thread.java:829)

Environment

VMware Cloud Director 10.6.x

Cause

There is an ongoing dvswitch migration for the cluster which is the purpose of the network change. Not all hosts have access to the same dvswitch on the backend. The host selector and placement engine for the VM is failing to find the target network on the hosts that is attempting for VM placement.

Resolution

Create affinity rules to keep the virtual machine on the host with the target network. The steps are here:
https://techdocs.broadcom.com/us/en/vmware-cis/vsphere/vsphere/8-0/vsphere-resource-management-8-0/using-drs-clusters-to-manage-resources/create-a-vm-host-affinity-rule.html

Considerations for VMware Cloud Director are here:
https://techdocs.broadcom.com/us/en/vmware-cis/cloud-director/vmware-cloud-director/10-6/creating-and-managing-vm-host-affinity-rules.html

 

To create and manage VM Placement Policy and Affinity, please see the following documentation:

Create a VM Placement Policy within a Provider VDC in VMware Cloud Director

Virtual Machine Affinity and Anti-Affinity in the VMware Cloud Director Tenant Portal

Other than using affinity rules, ensure that all the ESXi hosts in the Provider VDC cluster have access to the same networking.