How does batch_connect set_host affect app/VNC behavior?

In /etc/ood/config/apps/bc_desktop/submit/my_submit.yml.erb for OOD1, this line was commented out:

set_host: "host=$(hostname)"

Using the same file in OOD2, the desktop app didn’t run, with a novnc error, until the above line was restored to the file. Also (in OOD2 only), on the page to launch the app, the Host link (for shell) shows the short name of the compute node and doesn’t work without the set_host line, but with the set_host line shows the FQDN and works. (Outside of OOD, ssh from the OOD server to the compute node works using the short name of the compute node.)

I would like to understand how this set_host line is affecting app behavior. I thought that "host=$(hostname)" was the default value (shown at Method: OodCore::BatchConnect::Template#initialize — Documentation for ood_core (0.18.1)), so why would including this line, or not, change the behavior of the app?

Hi and thanks for posting!

The previous version may not have been checking the config correctly because if you go in and comment the hostname out there is no longer an actual default since OOD will read the config and since that default host is being retrieved programmatically from the system by that command commenting it out would mean the value can’t retrieved.

The relevant line for the Host link can be seen here:

I believe the wording of “default” is meant more to imply that this will be set assuming you don’t change it, such as commenting it out or to a different value.

I think the relevant part of the docs to understand the vnc app better would be here: VNC Batch Connect Options — Open OnDemand 2.0.13 documentation

And note that the top line mentions that the settings for the batch connect options also will apply to the vnc app, so that would include that set_hostname parameter.

I hope that is a helpful, but if anything is still unclear please feel free to ask or follow up.

That answers my question, thank you!