Adopt Singularity mechanisms provided by HTCondor
Migrate all the features provided by GWMS into using HTCondor provided features, transparently for the users.
This may happen in phases, as new features are added to HTCondor
From Greg Thain:
There currently isn't one master ticket for the singularity stuff. We did implement #6740: Allow MOUNT_UNDER_SCRATCH to be an expression in singularity jobs #6740 and #6731: Add SINGULARITY_EXTRA_ARGUMENTS so admins can add new singularity cli args #6731 as we discussed in the last meeting, and there is an open ticket on "implementing features to remove the need for wrapper scripts", #6599