What is the correct version of singularity to specify?

[aturner-epcc]

The lesson currently states that it has been tested with singularity v3.5.3 which is now quite old. We should probably update this but people will almost always want to use the most recent version that works for them due to security issues so maybe we need to rethink how we specify this?

[aturner-epcc]

Version on ARCHER2 at the moment is 3.5.3-1 and building with 3.7.x works works with 3.5.3. Need to check building with 3.8.x

[jcohen02]

Related to this, should we be highlighting that there are two different forks of singularity which currently have similar version numbers but which are likely to diverge over time?

As I understand it, the original open source Singularity project has ended up at https://github.com/hpcng/singularity and this has recently been forked by Sylabs Inc. as SingularityCE.

I believe both repositories are the same up to version 3.7.4 but are now going their own ways from 3.8.0 onwards...assuming this is correct, should we add a box with a brief explanation of this to help prevent any confusion?

[jcohen02]

For the most recent run of the course we opted to stick with 3.5.3 and used the v3.5.3-slim Docker Singularity image from quay.io.

Can we stick with this version for now @aturner-epcc and close the issue or would you like to keep this open with a view to revisiting it and maybe updating things in due course?

[liz-is]

I think it would be great to update the version of Singularity mentioned in this lesson - 3.5.3 is old enough that I initially thought this lesson must have been abandoned and not used recently, which doesn't seem to be the case!

[jcohen02]

Thanks for flagging this @liz-is, it's a good point. We originally stuck with 3.5.3 for some different reasons - firstly, as Singularity was forked and the open source versions became SingularityCE and Apptainer, there was some uncertainty about whether or how the versions would diverge. On this basis, we decided to focus on a release that was stable and where we new the content in the course would work as expected. At the same time, v3.5.3 is now getting on for 5 years old and I agree that this needs updating. We were also running the course on HPC platforms that were running v3.5.3 of Singularity which is another reason why we stuck with this release for some time.

When we run the course, we fork the repo and then make course-specific updates for a given run of the material. In more recent courses we've updated material to focus on using a more recent version of SingularityCE or Apptainer, e.g. this version of the course run at RSECon in 2023. We should push changes back to this reference version of the material and update things accordingly - I'll open an issue for this.