Error: "Unable to perform query" and UI fails to load when accessing VMware Cloud Director through a load balancer

Products

• VMware Cloud Director

Issue/Introduction

• You may see "Unable to perform query" after logging in to the VMware Cloud Director (VCD) UI.
• Browser developer tools show the error
  
  502 Bad Gateway
  
  
• Bypassing the Load Balancer by adding the IP and FQDN to your local machines host file fixes the issue..

Environment

VMware Cloud Director 10.6.x

Cause

Load Balancer profile settings are using default or insufficient values for Request/Response Header size and timeouts. This prevents larger payloads from passing through the Load Balancer.

Resolution

If using an NSX-T load balancer,

1. Login to the NSX-T Manager UI.
2. Navigate to "Networking > Network Services > Load Balancing > Profiles".
3. Identify the HTTP & HTTP profile in use and ensure the following configuration is in use:

• • Type: HTTPS
  • HTTP Request Header: X-Forward-For
  • Idle Timeout: 15 Seconds
  • Response Timeout: 60 Seconds
  • Request Header Size: 65535
  • Response Header Size: 50000

These details are outlined in the VMware Cloud Director Cell Load Balancing Configuration

If third-party load balancers are deployed, access the respective management console to review and update the HTTP/HTTPS profiles to match requirements.

Additional Information

To verify, inspect the network tab in browser developer tools. Refresh the VCD page and look for a failed request to cloudapi.

If the load balancer is misconfigured, the request will fail with a 502 Bad Gateway error.