Description
This may be partially "by design" (but possibly worth a discussion). When loading an image from a tar, the loaded image unconditionally replaces existing image(s).
1. Failing to load image replaces existing image with empty index
The following example loads a multi-platform image from a tar (not all variants are present in the tar);
$ docker image load -i image.tar
Loaded image: alpine:latest
$ docker image ls --tree
IMAGE ID DISK USAGE CONTENT SIZE USED
alpine:latest beefdbd8a1da 20.6MB 11.1MB
├─ linux/s390x 2b5b26e09ca2 3.46MB 3.46MB
├─ linux/ppc64le c7a6800e3dc5 3.57MB 3.57MB
├─ linux/arm64/v8 9cee2b382fe2 13.6MB 4.09MB
├─ linux/amd64 33735bd63cf8 0B 0B
├─ linux/arm/v6 50f635c8b04d 0B 0B
├─ linux/arm/v7 f2f82d424957 0B 0B
├─ linux/386 b3e87f642f5c 0B 0B
└─ linux/riscv64 80cde017a105 0B 0B
When trying to load a platform-variant from the tar that's not included, an error is produced, but the image is replaced regardless, so now resulting in an empty image reference;
$ docker image load -i image-multiple.tar --platform=linux/ppc64le
requested platform (linux/ppc64le) not found: not found
docker image ls --tree
IMAGE ID DISK USAGE CONTENT SIZE USED
alpine:latest beefdbd8a1da 0B 0B
2. Loading different variant of the same manifest-index replaces existing variants
The following loads a single variant from a tar;
$ docker image load -i image-multiple.tar --platform=linux/amd64
Loaded image: alpine:latest
$ docker image ls --tree
IMAGE ID DISK USAGE CONTENT SIZE USED
alpine:latest beefdbd8a1da 12.1MB 3.63MB
├─ linux/amd64 33735bd63cf8 12.1MB 3.63MB
├─ linux/arm/v6 50f635c8b04d 0B 0B
├─ linux/arm/v7 f2f82d424957 0B 0B
├─ linux/arm64/v8 9cee2b382fe2 0B 0B
├─ linux/386 b3e87f642f5c 0B 0B
├─ linux/ppc64le c7a6800e3dc5 0B 0B
├─ linux/riscv64 80cde017a105 0B 0B
└─ linux/s390x 2b5b26e09ca2 0B 0B
Loading a different variant from the same image replaces the available variants of the multi-platform image with the newly imported variant;
$ docker image load -i image-multiple.tar --platform=linux/s390x
Loaded image: alpine:latest
$ docker image ls --tree
IMAGE ID DISK USAGE CONTENT SIZE USED
alpine:latest beefdbd8a1da 11.9MB 3.46MB
├─ linux/s390x 2b5b26e09ca2 11.9MB 3.46MB
├─ linux/amd64 33735bd63cf8 0B 0B
├─ linux/arm/v6 50f635c8b04d 0B 0B
├─ linux/arm/v7 f2f82d424957 0B 0B
├─ linux/arm64/v8 9cee2b382fe2 0B 0B
├─ linux/386 b3e87f642f5c 0B 0B
├─ linux/ppc64le c7a6800e3dc5 0B 0B
└─ linux/riscv64 80cde017a105 0B 0B
❓ do we want to have an option to append to the existing image, in situations where the root manifest-index is the same?
Description
This may be partially "by design" (but possibly worth a discussion). When loading an image from a tar, the loaded image unconditionally replaces existing image(s).
1. Failing to load image replaces existing image with empty index
The following example loads a multi-platform image from a tar (not all variants are present in the tar);
When trying to load a platform-variant from the tar that's not included, an error is produced, but the image is replaced regardless, so now resulting in an empty image reference;
2. Loading different variant of the same manifest-index replaces existing variants
The following loads a single variant from a tar;
Loading a different variant from the same image replaces the available variants of the multi-platform image with the newly imported variant;
❓ do we want to have an option to append to the existing image, in situations where the root manifest-index is the same?