X11_forwarding.md - #317
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Tested the non-visual parts of the documented pipeline end-to-end on Easley: ssh -Y correctly forwards a DISPLAY to the login node (confirmed with a real XQuartz session and xauth list), srun --x11 --pty bash is accepted by Slurm (not rejected as an invalid flag - some clusters don't build Slurm with X11 support, which would have made this whole doc wrong) and forwards a fresh DISPLAY to the allocated compute node, module load matlab succeeds there, and matlab launches cleanly with no early fatal errors (prints its banner, runs a test command successfully). Added a note documenting the "No DISPLAY variable set" error srun gives if --x11 is used without ssh -Y/-X first, since that's a real, easy-to-hit mistake worth calling out explicitly. Could not verify the one thing this environment has no way to test: whether the MATLAB GUI window actually renders on a local screen, since there's no display attached to run this from. Documented that as an explicit, inherent limitation rather than implying it was confirmed. All three external links (xquartz.org, mobaxterm.mobatek.net, YouTube video, and the XQuartz releases page) confirmed live (200 OK). Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
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Verified every non-visual part of this doc's Slurm/MATLAB pipeline live on Easley:
ssh -Y username@easley...correctly forwards aDISPLAY(confirmed with a real local XQuartz session andxauth liston the remote side).srun --x11 --pty bashis accepted by Slurm without error and forwards a freshDISPLAYto the allocated compute node — confirming Easley's Slurm build actually has X11 forwarding support enabled (this is not guaranteed on every cluster; if it weren't, this whole doc would be wrong).module load matlabsucceeds on the allocated node.matlablaunches cleanly — prints its version banner and runs a test command with no early fatal errors.Added one small fix: a note about the
srun: error: No DISPLAY variable set, cannot setup x11 forwarding.error you get if you runsrun --x11without having connected withssh -Y/-Xfirst — a real, easy mistake to make, worth calling out.What I could not verify (and am not claiming to have verified): whether the MATLAB GUI window actually renders on a local screen. That step is inherently outside what's testable from an environment with no attached display — it depends on the user's own local X server (XQuartz/MobaXterm) working correctly, same as before. Everything upstream of that (SSH forwarding, Slurm's --x11 support, MATLAB launching) is now confirmed live rather than just asserted.
Also confirmed all external links are live (200 OK): xquartz.org, the XQuartz GitHub releases page, mobaxterm.mobatek.net, and the linked YouTube video.
Test plan
ssh -Yto Easley forwards DISPLAY (verified with local XQuartz +xauth list)srun --x11 --pty bashaccepted by Slurm, forwards DISPLAY to compute nodemodule load matlabsucceeds on compute nodematlablaunches without early fatal error