VNC

VNC Access

VNC provides alternate remote desktop access to Windows instances through 7lbd but has notable performance limitations:

• Significant mouse lag and poor overall performance
• Guacamole is the recommended browser connection method
• VNC console (via websockify) is provided only for troubleshooting VM boot issues

Configuration

Enable/disable VNC access in submit.yml.erb:

- "--iso-netns-options"
- "guacamole=1,vnc=1"

Setting vnc=1 enables VNC access, while vnc=0:

• Disables websockify service
• Removes VNC button from job card interface

Technical Details

The --iso-netns-options flag in Slurm triggers the Spank plugin to set the SLURM_SPANK__SLURM_SPANK_OPTION_spank_iso_netns_iso_netns_options environment variable in Open OnDemand. This environment variable determines whether guacamole or VNC services should be initialized for the job.