Error: vCenter Server is unable to find a master vSphere HA agent in cluster

Products

• VMware vCenter Server

Issue/Introduction

vSphere HA is not working on your cluster:

• You see the following error at the cluster level in vCenter: vCenter Server is unable to find a master vSphere HA agent in cluster <cluster_name> in <datacenter_name>
• You have recently reset the VMware Update Manager database
• When attempting to re-enable HA at the cluster level, you may see the following errors:
  • A general system error occurred: Installing HA components failed on the cluster: domain-##
  • Cannot complete the configuration of the vSphere HA agent on the host. "Applying HA VIBS on the cluster encountered a failure" Failed installing HA component on the host: host-##
• Your vCenter cannot access the Internet and requires images and modules to be manually uploaded using Lifecycle Manager

 

Environment

vSphere 8.x

Cause

After the VMware Update Manager Database gets reset, images and modules stored in the database are removed. This causes the cluster to become non-compliant as the hosts have images and modules that cannot be referenced in the database. 

Resolution

For each cluster that is exhibiting the problem:

1. In the vCenter UI, select the cluster and select the Updates tab. 
2. Select Image, then in the Image box on the right, select the ellipses menu next to Edit and select Export
3. Select ZIP (offline bundle) and select Export. The zip file will start to download. 
4. Upload the zip file by selecting the menu in the top left of the vCenter UI and selecting Lifecycle Manager.
5. If you have multiple vCenter servers, select the vCenter that has the cluster you are importing the image for. 
6. Select Actions, then Import Updates and select the zip file you exported.
7. Go back to your cluster, select Image, then in the Image box on the right, select the ellipses menu next to Edit and select Export
8. Select JSON to save the image definition JSON file
9. Edit the file and remove the reference to vmware-fdm if it exists as it does not need to be added as a component in the image. 
10. Import the modified JSON by selecting Import in the same menu from step 7.
11. In the Image Compliance box, select Check Compliance. If any additional required modules are flagged as missing, upload them in the same fashion as step 6.
12. Run Check Compliance again to ensure your cluster is compliant. 
13. Select your cluster and go to Configure > vSphere Availability > Edit next to vSphere HA. 
14. Select the toggle button next to vSphere HA to enable it. 

Additional Information

Working With the vSphere Lifecycle Manager Depot
Working with Images