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Squash File System and Singularity

note

View available datasets on the Datasets page.

Working with Datasets​

Writable ext3 overlay images have conda environments installed inside, Singularity can work with squashFS for fixed datasets, such as the coco datasets. Here's an example using the my_pytorch.ext3 we created in the last tutorial Apptainer with Conda:

[NetID@log-1 ~]$ singularity exec \
--overlay /scratch/<NetID>/pytorch-example/pytorch1.8.0-cuda11.1.ext3:ro \
--overlay /scratch/work/public/ml-datasets/coco/coco-2014.sqf:ro \
--overlay /scratch/work/public/ml-datasets/coco/coco-2015.sqf:ro \
--overlay /scratch/work/public/ml-datasets/coco/coco-2017.sqf:ro \
/scratch/work/public/singularity/cuda11.1-cudnn8-devel-ubuntu18.04.sif /bin/bash

If you have many tiny files as fixed datasets, please make squashFS files to work with Singularity. Here is an example:

  1. Make a temporary folder in /state/partition1, it is a folder in local hard drive on each computer node
[NetID@log-3 NetID]$ srun --pty /bin/bash
srun: job 62890341 queued and waiting for resources
srun: job 62890341 has been allocated resources
[NetID@cm002 NetID]$ mkdir -p /state/partition1/<NetID>
[NetID@cm002 NetID]$ cd /state/partition1/<NetID>
  1. Unzip files there, for example
[NetID@cm002 NetID]$ tar -vxzf /projects/work/public/examples/squashfs/imagenet-example.tar.gz
  1. Change access permissions in case we'll share files with others
[NetID@cm002 NetID]$ find imagenet-example -type d -exec chmod 755 {} \;
[NetID@cm002 NetID]$ find imagenet-example -type f -exec chmod 644 {} \;
  1. Convert to a single squashFS file on host
[NetID@cm002 NetID]$ mksquashfs imagenet-example imagenet-example.sqf  -keep-as-directory

For more details on working with squashFS, please see details from SquashFS documentation.

  1. Copy this file to /scratch
[NetID@cm002 NetID]$ cp -rp /state/partition1/<NetID>/imagenet-example.sqf /scratch/<NetID>/.
  1. To test, files are in /imagenet-example inside Singularity container:
[NetID@cm002 NetID]$ singularity exec --overlay /scratch/<NetID>/imagenet-example.sqf:ro /scratch/work/public/singularity/ubuntu-20.04.1.sif /bin/bash
Singularity> find /imagenet-example | wc -l
1303
Singularity> find /state/partition1/<NetID>/imagenet-example | wc -l
1303
  1. To delete the temporary folder on host
[NetID@cm002 NetID]$ rm -rf /state/partition1/<NetID>