Bootstrap from Singularity image on GHCR?

[ArneNx]

I was wondering if it is in any way possible to use a singularity image that was pushed to ghcr.io with this workflow as the source for bootstrapping in a new singularity definition?

[vsoch]

Yep! You should be able to bootstrap oras, which is the same way we push. See https://sylabs.io/guides/3.5/user-guide/appendix.html#oras-bootstrap-agent

[ArneNx]

Thanks for the quick response. I tried that and got:

FATAL:   While performing build: conveyor failed to get: while fetching library image: failed to get checksum for oras://ghcr.io/sinzlab/pytorch-singularity:v3.9-torch1.10.2-dj0.12.7.def: no layer found corresponding to SIF image

[vsoch]

What if you just download Oras and pull with -a?

it’s after 1am here so I’ll probably need to pick up helping tomorrow.

[ArneNx]

Oras without -a gives me

Downloaded empty artifact
Pulled ghcr.io/sinzlab/pytorch-singularity:v3.9-torch1.10.2-dj0.12.7.def
Digest: sha256:c2c791486d4705423a5a8058c0b5a51230272957ac5a24a7499f33663cb86377

With -a it seems to work (container is downloaded):

Downloaded 602051779ceb container.sif
Pulled ghcr.io/sinzlab/pytorch-singularity:v3.9-torch1.10.2-dj0.12.7.def
Digest: sha256:c2c791486d4705423a5a8058c0b5a51230272957ac5a24a7499f33663cb86377

Normal singularity pull gives the same error message as Bootstrap.
The problem is not too urgent. So postponing it until tomorrow is not a problem.

[vsoch]

With -a it seems to work (container is downloaded):

Okay that's our sanity check! The -a says "allow all artifact types" which is why the first doesn't work and the second does.

And I installed singularity 3.9.0 and it does seem to be downloading (albeit very slowly):

 singularity --debug pull oras://ghcr.io/sinzlab/pytorch-singularity:v3.9-torch1.10.2-dj0.12.7.def
DEBUG   [U=1000,P=438534]  persistentPreRun()            Singularity version: 3.9.0-rc.1+26-gf57577214
DEBUG   [U=1000,P=438534]  persistentPreRun()            Parsing configuration file /usr/local/etc/singularity/singularity.conf
DEBUG   [U=1000,P=438534]  handleConfDir()               /home/vanessa/.singularity already exists. Not creating.
DEBUG   [U=1000,P=438534]  getCacheParentDir()           environment variable SINGULARITY_CACHEDIR not set, using default image cache
INFO    [U=1000,P=438534]  pull()                        Downloading oras image
DEBUG   [U=1000,P=438534]  func1()                       Will pull oras image container.sif to /home/vanessa/.singularity/cache/oras/tmp_4250792211

$ ls -l /home/vanessa/.singularity/cache/oras/
total 118784
-rwx------ 1 vanessa vanessa 121634816 Feb  8 05:26 tmp_4250792211
vanessa@vanessa-ThinkPad-T450s:~$ ls -l /home/vanessa/.singularity/cache/oras/
total 230400
-rwx------ 1 vanessa vanessa 235929600 Feb  8 05:27 tmp_4250792211

Going to wait it out and make sure it finishes. Okay it just finished - image seems okay!

DEBUG   [U=1000,P=438534]  Init()                        Image format detection
DEBUG   [U=1000,P=438534]  Init()                        Check for sandbox image format
DEBUG   [U=1000,P=438534]  Init()                        sandbox format initializer returned: not a directory image
DEBUG   [U=1000,P=438534]  Init()                        Check for sif image format
DEBUG   [U=1000,P=438534]  Init()                        sif image format detected
$ ls
pytorch-singularity_v3.9-torch1.10.2-dj0.12.7.def.sif
vanessa@vanessa-ThinkPad-T450s:~/go/src/github.com/sylabs/singularity/builddir$ singularity shell pytorch-singularity_v3.9-torch1.10.2-dj0.12.7.def.sif 
Singularity> 

So I think if a basic singularity pull oras:// isn't working for you it might be a bug with singularity? I just built 3.9.0 from sylabs - give that repository a shot and if it still is an error it sounds like maybe a bug to report - something with using the wrong puller (library instead of oras) or maybe even a memory issue.

E.g., based on seeing:

while fetching library image

it looks like your install is trying to install oras from the library? That might be the issue.

[ArneNx]

You were right. I had version 3.6.4 installed.
Trying it on another server with 3.8.5 worked for me.
Thanks a lot for your help!