Aria Operations dashboards do not populate data with "Unable to connect to VC" or "Connection refused" errors

Products

• VCF Operations/Automation (formerly VMware Aria Suite)

Issue/Introduction

• Aria Operations dashboards are not working.

• The VALIDATE CONNECTION tests fail or time out for the vCenter adapter instance.

• Data collections cannot be started.

• Adapter logs indicate the error: "Unable to connect to VC." or "Connection refused".

• Verify the following configuration and network parameters:

  • Storage Consistency: Ensure there are no disk sizing mismatches between the primary and replica nodes (e.g., verify the /storage/db filesystems match in capacity across nodes).

  • Storage Capacity: Ensure each cluster nodes has ample disk space by running df -h.

  • Network Connectivity: Confirm network traffic is flowing cleanly over port 443. From each Aria Operations node, test connectivity on each cluster node while logged into an SSH session as root using:

    • Ping with a large MTU: ping -s 1453 <vcenter_ip>

    • Curl test: curl telnet://<vcenter_ip>:443

    • SSL test: openssl s_client -connect <vcenter_ip>:443

Note: The ping should succeed, the curl command should show a "connected to..." message. The SSL test should show the certificate data.

Environment

Aria Operations 8.x

VMware vCenter 7.x, 8.x 

Cause

This issue occurs when the target vCenter Server is heavily resource-constrained. If the vCenter Server routinely experiences high resource utilization (e.g., 70-80% CPU usage and almost fully consumed RAM), it leads to inconsistent or severely delayed API responses.

Because Aria Operations requires the vCenter API to respond in a timely fashion, these delays cause data collections to consistently fail and prevent the connection validation process from completing successfully.

Resolution

To resolve this issue, the resource contention on the target vCenter Server must be addressed to restore normal API responsiveness.

1. Reboot the target vCenter Server: This clears the immediate resource constraints, resolves connection refused errors, and restores API performance. If this issue reappears in a few days or weeks, consider adding resources to vCenter.

2. Once vCenter is back online, log into the Aria Operations UI.

3. Navigate to the vCenter adapter instance configuration.

4. Click VALIDATE CONNECTION to confirm that connectivity has been restored.

5. Verify that data collections have successfully restarted and dashboards are populating as expected.