Cannot SSH or Log In to NSX Manager: Login Prompt Missing and Cluster Status Degraded

Products

• VMware NSX

Issue/Introduction

Customers may encounter an issue where they are unable to log in via SSH to an NSX Manager node because the login prompt does not appear (is missing or obscured).

Concurrently, the NSX Manager cluster may be in a degraded state, and attempts to check the status of the SSH service via the console command get service SSH will yield no output.

Environment

VMware NSX

Cause

The root cause of the issue is the accumulation of old core dump files on the NSX Manager nodes.

The presence of these files interferes with the normal operation, resource availability, and command execution of the NSX Managers, leading to the observed instability, failure of the cluster, and command execution errors.

Resolution

To immediately resolve the issue and restore cluster stability, clear all old core dump files from all NSX Manager nodes by executing the following command in the NSX Manager console:

del core-dump all


Procedure:

• Access the console of an NSX Manager node (e.g., via the hypervisor console).
• Log in with an administrative user (e.g., admin).
• Run the command: del core-dump all.
• Repeat the command on all other NSX Manager nodes in the cluster.

Verification:

• After successfully clearing the core dump files on all nodes:
• The SSH login prompt will appear correctly when attempting to connect via SSH (e.g., PuTTY).
• The command get service ssh will execute successfully and provide the service status output.
• The NSX Manager cluster state will also transition from degraded to stable.

Additional Information

Reference Link: After an upgrade to NSX 4.x, the alarm Application on NSX node <nsx manager> has crashed is generated