Docker requires sudo privilege and therefore it is not supported on the HPC system. To use a Docker image you will need to convert it into Apptainer.

Convert a Docker image

There are several ways to convert a Docker image:

  • Download a remote image from Docker Hub
  • Build from a local image cached in Docker daemon
  • Build from a definition file (advanced)

Instructions are provided in each of the following sections.

Docker Hub

Docker images hosted on Docker Hub can be downloaded and converted in one step via the apptainer pull command:

module load apptainer
apptainer pull docker://account/image

Use the exact same command as you would for docker pull.

Docker daemon

(Taken from Apptainer 3.5 User Guide)

You can convert local Docker images into Apptainer (e.g. on your personal computer).
Suppose you have the godlovedc/lolcow:latest image cached by Docker:

$ sudo docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
godlovedc/lolcow    latest              577c1fe8e6d8        16 months ago       241MB

You can build an Apptainer image from it via:

$ apptainer build lolcow_from_docker_cache.sif docker-daemon://godlovedc/lolcow:latest
INFO:    Starting build...
Getting image source signatures
Copying blob sha256:a2022691bf950a72f9d2d84d557183cb9eee07c065a76485f1695784855c5193
 119.83 MiB / 119.83 MiB [==================================================] 6s
Copying blob sha256:ae620432889d2553535199dbdd8ba5a264ce85fcdcd5a430974d81fc27c02b45
 15.50 KiB / 15.50 KiB [====================================================] 0s
Copying blob sha256:c561538251751e3685c7c6e7479d488745455ad7f84e842019dcb452c7b6fecc
 14.50 KiB / 14.50 KiB [====================================================] 0s
Copying blob sha256:f96e6b25195f1b36ad02598b5d4381e41997c93ce6170cab1b81d9c68c514db0
 5.50 KiB / 5.50 KiB [======================================================] 0s
Copying blob sha256:7f7a065d245a6501a782bf674f4d7e9d0a62fa6bd212edbf1f17bad0d5cd0bfc
 3.00 KiB / 3.00 KiB [======================================================] 0s
Copying blob sha256:70ca7d49f8e9c44705431e3dade0636a2156300ae646ff4f09c904c138728839
 116.56 MiB / 116.56 MiB [==================================================] 6s
Copying config sha256:73d5b1025fbfa138f2cacf45bbf3f61f7de891559fa25b28ab365c7d9c3cbd82
 3.33 KiB / 3.33 KiB [======================================================] 0s
Writing manifest to image destination
Storing signatures
INFO:    Creating SIF file...
INFO:    Build complete: lolcow_from_docker_cache.sif

Note that this requires sudo privilege. You can then transfer the image to the HPC system.

Definition file

If you are building from a definition file, you can bootstrap from a Docker base container.

Bootstrap: docker
From: account/image:version
...

Use a Docker image

After you have obtained the converted *.sif Apptainer image, you can use it by:

module load apptainer
apptainer run|exec|shell image.sif

Please visit this page for more information on run, shell, and exec.

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