Here's one that's already been prepared: https://susestudio.com/a/Sn0thq/docker-base-image
You'll want to download "USB drive / Hard Disk Image" which we'll use later.
> tar -xvf MyOpenSUSEImage.oem.tar.gz
We need to inspect the hard disk image to find out where the partition is, so we can mount it.
Use parted for this:
> parted MyOpenSUSEImage.raw
GNU Parted 3.1
Using .....
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) unit
Unit? [compact]? B
(parted) print
Model: (file)
Disk ......: 305135616B
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags:
Number Start End Size Type File system Flags
1 1048576B 305135615B 304087040B primary ext3 boot, type=83
(parted) q
> mkdir target
> mount -o loop,ro,offset=1048576 MyOpenSUSEImage.raw target
> cd target
> tar -cpf ../opensuse.tar *
> cd ..
> docker import opensuse.tar my-repo/opensuse
> docker run -t -i my-repo/opensuse /bin/bash
> docker push my-repo/opensuse