Sharing a file system to the docker container in the HTCondor setup

[katilp]

I would like to mount a shared filesystem other than the HTCondor scratch volume to the docker containers in the HTCondor setup.

I have followed the instructions and mounted successfully a shared filesystem /shared to the access and execute points.

I understand from the HTCondor admin manual that I should set up this mount with:

An administrator of a machine can optionally make additional directories on the host machine readable and writable by a running container. To do this, the admin must first give an HTCondor name to each directory with the DOCKER_VOLUMES parameter. Then, each volume must be configured with the path on the host OS with the DOCKER_VOLUME_DIR_XXX parameter. Finally, the parameter DOCKER_MOUNT_VOLUMES tells HTCondor which of these directories to always mount onto containers running on this machine.

Presumably, in my case - if I want to mount the host /shared to the container /shared - this would be

DOCKER_VOLUMES = SHARED
DOCKER_VOLUME_DIR_SHARED = /shared
DOCKER_MOUNT_VOLUMES = SHARED

Would this be doable somewhere during the HTCondor installation which I believe happens here

Thanks for any advise!

[tpdownes]

I agree that we don't yet have a well integrated solution for adding extra HTCondor snippets into the final system configuration. I have tried a couple workarounds but have not landed upon a good solution. I will follow up next week with you.

Ideally, I think the configuration snippets would be suppliable not on HTCondor install module (which configures every image) but would be added to the access/central manager/execute point modules so that they can be configured separately. We do accept community pull requests if you are willing to do this.

[katilp]

Thanks!

In the same go, if I may, it would be great to have an option to store the docker images in that mounted volume.

In principle, that could go in here as something like

- name: Change Docker default storage
  copy:
    content: '{\n"data-root": "{{ mounted_dir }}"\n}'
    dest: /etc/docker/daemon.json
  when: mounted_dir is defined and some_condition is true

That's what I would need (with our 30 G image 😬), but I guess not everyone would want it so it would be good to have an option (some_condition) in an option.

Does that make sense?