Edit: Summary

Initial report

Over at Jupyter Docker Stacks, we have been trying create the initial Conda environment for our base-notebook by using Micromamba instead of Miniforge. We have been plagued by sporadic hangs in our multi-arch Docker build process on GH Actions at a rate of ~20% of all runs when for aarch64 we RUN the command

./micromamba install --root-prefix=/opt/conda --prefix=/opt/conda -vv --yes python=3.9 mamba notebook jupyterhub jupyterlab

The hang occurs sometime between the end of extraction and the beginning of linking. The last message printed during an unsuccessful run is something like

  #29 188.0 debug    libmamba Extracted to '/opt/conda/pkgs/mistune-0.8.4-py39h14843e3_1005'

without proceeding to a line like

#29 178.0 Linking pandoc-2.17.1.1-h8af1aa0_0

Execution hangs without any further output until the 6h limit is reached.

References

(in chronological order)

• Mamba sporadically hangs when building jupyter/docker-stacks arm64 image
• Original PR in jupyter/docker-stacks to replace MiniForge with Micromamba.
• Partially understood/isolated the problem
• This bug report
• @jonashaag patches my jupyter/docker-stacks PR to disable concurrency, and I confirm that it appears to work
• @jonashaag patches libmamba to disable subprocesses when extract_threads=1
• Discussion returns to this thread