Webapp client fails to start - stuck at starting application due to stale X11 lock files - Spectrum OneClick

Products

• Network Observability
• Spectrum

Issue/Introduction

Spectrum OneClick WebApp fails to launch and remains in a "starting application" state. This occurs when the Webswing process cannot connect to the X11 window server because of stale lock files or sockets left behind by a previous Xvfb crash.

 

The following error appears in the webtomcat/logs/catalina.out or webswing.log: Caused by: java.awt.AWTError: Can't connect to X11 window server using ':99' as the value of the DISPLAY variable.

Environment

• Product: DX NetOps Spectrum / OneClick. (Any supported version)
• OS: Linux (RHEL/CentOS/SLES)
• Component: Webswing / WebTomcat

 

Cause

A previous instance of the Xvfb (X virtual frame buffer) service crashed or was terminated improperly, leaving behind lock files in the /tmp directory. These files prevent new Xvfb instances from binding to the required display (usually :99).

Resolution

1. Stop the webtomcat service.  (from $SPECROOT/webtomcat/bin run ./stopWebTomcat.sh)
2. Identify and stop the Xvfb service if it is still partially running.
3. Remove the stale lock and socket files:
• rm -f /tmp/.X99-lock
• rm -f /tmp/.X11-unix/X99 (Note: Replace '99' with the display number used in your environment if different).
4. Restart the webtomcat service.   (from $SPECROOT/webtomcat/bin run ./startWebTomcat.sh)