nerdctl save format

[eldanh]

How can I save an image as a tar in docker format (having 'repositories' and 'manifest.json') and not the 'blobs' format?

[fahedouch]

==> https://github.com/containerd/nerdctl#whale-nerdctl-save

nerdctl save implement both Docker Image Spec v1.2 and OCI Image Spec v1.0.

[eldanh]

Hi, I tried and could not generate the proper format.

Tried executing 'nerdctl save' as such:

nerdctl save XXX --output x.tar

but am getting this format

drwxr-xr-x 0/0 0 1970-01-01 02:00 blobs/
drwxr-xr-x 0/0 0 1970-01-01 02:00 blobs/sha256/
-r--r--r-- 0/0 1580 1970-01-01 02:00 blobs/sha256/565XXXXXXXXXXXXXXXXXX6ad
-r--r--r-- 0/0 1750976 1970-01-01 02:00 blobs/sha256/5b0XXXXXXXXXXXXXXXXXX1a9
-r--r--r-- 0/0 3490 1970-01-01 02:00 blobs/sha256/ca8XXXXXXXXXXXXXXXXXX2ab
-r--r--r-- 0/0 8651777 1970-01-01 02:00 blobs/sha256/dedXXXXXXXXXXXXXXXXXXe1d
-rw-r--r-- 0/0 330 1970-01-01 02:00 index.json
-rw-r--r-- 0/0 632 1970-01-01 02:00 manifest.json
-r--r--r-- 0/0 30 1970-01-01 02:00 oci-layout

while I need the docker save format as such (from 'docker save')

drwxr-xr-x 0/0 0 2021-12-19 01:27 d09XXXXXXXXXXXXXXXXXXXb61/
-rw-r--r-- 0/0 3 2021-12-19 01:27 d09XXXXXXXXXXXXXXXXXXXb61/VERSION
-rw-r--r-- 0/0 401 2021-12-19 01:27 d09XXXXXXXXXXXXXXXXXXXb61/json
-rw-r--r-- 0/0 5879808 2021-12-19 01:27 d09XXXXXXXXXXXXXXXXXXXb61/layer.tar
-rw-r--r-- 0/0 604 1970-01-01 02:00 manifest.json
-rw-r--r-- 0/0 106 1970-01-01 02:00 repositories

I also tried to create the format with the 'nerdctl build' but same 'blob' format result, as such:

nerdctl build -t XXX --output type=docker,dest=./a.tar .

[AkihiroSuda]

That is "proper" format covering both Docker Image Spec (manifest.json) and OCI Image Spec (index.json).
The blobs are referred by the both JSONs.