Discussion from the Chat

1. Training & Tutorials (ATLAS, RECAST, Snakemake, REANA)

Discussion on whether to include this topic in analysis software trainings is ongoing.

There used to be some RECAST-specific sessions, e.g.:

https://alexschuy.github.io/2020-08-27-usatlas-recast-tutorial/index.html

Clarification: reference was to the week-long ATLAS software tutorials:

https://atlas-software.docs.cern.ch/analysis/

Additional training material and events also exist.

Request for Tutorials

Question:

Could you provide the link to Snakemake/REANA tutorials?

Response:

Snakemake tutorial:

https://snakemake.readthedocs.io/en/stable/tutorial/tutorial.html

REANA tutorial:

https://hsf-training.github.io/hsf-training-reana-webpage/

(Note: The REANA tutorial mostly uses Yadage; Snakemake parts still need to be finalized.)

2. REANA Usage (LHCb Example)

REANA usage in LHCb is currently limited.

One example involved running an analysis on REANA using Snakemake underneath, which made setup relatively smooth:

https://indico.cern.ch/event/1380367/contributions/5880485/attachments/2831210/4946726/M_Sarpis_LHCb_Analysis_with_Snakemake.pdf

3. Snakemake with HTCondor

Snakemake works on lxplus via HTCondor using the following profile:

https://github.com/Snakemake-Profiles/htcondor

Executor plugin repositories:

• https://github.com/jannisspeer/snakemake-executor-plugin-htcondor

• https://github.com/htcondor/snakemake-executor-plugin-htcondor

Identified Issue

The HTCondor executor plugin does not allow specifying JobFlavour.

Jobs are submitted with the default 20-minute time limit, causing longer jobs to be aborted.

Possible Solution

Supporting the necessary Condor classads for JobFlavour should be straightforward (documentation or implementation update).

In the plugin README, custom job resources must be defined with a classad_ prefix, e.g.:

classad_JobFlavour

Usability Feedback

It can be confusing that there is:

• an HTCondor cluster plugin, and

• a profile that uses the generic-cluster plugin under the hood.

Some participants expressed willingness to help improve the plugin.

Additionally, some changes appear to have been submitted upstream:

https://github.com/jannisspeer/snakemake-executor-plugin-htcondor/pull/16

4. SLURM, MPI & GPU Support

Question:

Is Snakemake more modern now? Can we run SLURM/MPI jobs?

Response:

Yes — there is a SLURM executor plugin:

https://snakemake.github.io/snakemake-plugin-catalog/plugins/executor/slurm.html

The SLURM plugin supports:

• MPI jobs

• GPU jobs

Extended SLURM feature support is on the roadmap.

5. Grid Executors (ATLAS, CMS, LHCb)

A current limitation of Snakemake is lack of grid executor support.

Potential improvements:

• ATLAS: PanDA executor plugin

• CMS: CRAB integration

• LHCb: Possibly DIRAC

Such integrations would significantly increase adoption.

6. Workflow Visualization

Question:

Are there tools to draw Snakemake workflows as diagrams?

Response:

Workflow visualization is an integral part of Snakemake.

7. Cross-Community Similarities & Computing Strategy

There are strong similarities between:

• Particle physics

• Astronomy

• Other scientific communities

Computational workflow needs are largely similar.

Sociological factors often play as large a role as technical ones.

There are also plans to unify approaches to scientific computing in overlapping areas (e.g., within the ESCAPE project), including tools such as:

• Rucio

• REANA

User interface design and well-structured examples were highlighted as important adoption factors.

8. Software Provisioning (EESSI)

There is a long-term plan to provide Snakemake via the

European Environment for Scientific Software Installations (EESSI).

Development progress is ongoing but slow.