NSX Manager Cluster Status displays "UNAVAILABLE" in the UI when accessed via Virtual IP

Products

• VMware NSX

Issue/Introduction

Users may encounter a scenario where the NSX Manager cluster health is incorrectly reported in the Graphical User Interface (GUI). While the cluster remains functional and healthy at the CLI level, the UI presents a critical status error.

Logging into the NSX Manager UI using the Virtual IP (VIP) shows the cluster status as UNAVAILABLE under System > Appliances.

Logging into an individual NSX Manager node directly (using its management IP) shows the cluster status as STABLE.

Running the CLI command get cluster status on any node shows all services are UP and the cluster is STABLE.

You can view the configuration and status of the NSX Manager cluster from the NSX Manager UI.

Environment

VMware NSX

Cause

The issue is caused by DNS timeout latency during the execution of internal system scripts.

When the UI requests cluster health data, the NSX Manager performs network-related lookups. If the NSX Manager is configured with an unreachable or invalid DNS server, the following occurs:

The system attempts to query the DNS servers sequentially as listed in the configuration.

The query to the unreachable DNS server must time out before the system attempts the next server in the list.

This sequential delay (often 15–30 seconds) causes the internal API request to exceed the UI's processing threshold.

Because the VIP adds a layer of request redirection, the cumulative latency results in the UI failing to render the cluster status, defaulting to "UNAVAILABLE."

Resolution

To resolve this issue, remove the unreachable DNS server(s) from the NSX Manager configuration to eliminate the lookup latency.

Identify the faulty DNS server: From the NSX Manager CLI, attempt to ping each configured DNS server to verify reachability.

Remove the unreachable server: Use the following CLI command on each NSX Manager node: del dns-server <IP-Address>

Verify the configuration: Ensure only functional, reachable DNS servers remain: get dns-servers

Confirm UI Status: Log out of the NSX Manager VIP and log back in. Navigate to System > Appliances and verify the status now shows as STABLE.