docker2oci

A tool to convert images saved from docker save to oci format image.

Installation

For go up to version 1.17, use:

go get github.com/coolljt0725/docker2oci

For go version 1.17+, use:

go install github.com/coolljt0725/docker2oci@latest

Build

To build docker2oci, the following build system dependencies are required:

• Go 1.8.x or above
• vndr tool

Build steps:

$ git clone https://github.com/coolljt0725/docker2oci $GOPATH/src/github.com/coolljt0725/docker2oci
$ cd $GOPATH/src/github.com/coolljt0725/docker2oci
$ make

Example

$ docker save -o busybox.tar busybox
$ docker2oci -i busybox.tar busybox

or

$ docker save busybox | docker2oci busybox

Check the the image:

$ find busybox -type f
busybox/blobs/sha256/8baf43d43a34a0e6649c254b0200c2406fc40a501a852ba51a86ac3672dc0441
busybox/blobs/sha256/40a114053d955a2b80ee2cf6e13410b28b59594ceee9036b41e12c42d3e16615
busybox/blobs/sha256/8ac8bfaff55af948c796026ee867448c5b5b5d9dd3549f4006d9759b25d4a893
busybox/index.json
busybox/oci-layout
$ oci-image-tool validate busybox
oci-image-tool: reference "latest": OK
busybox: OK
Validation succeeded
$ mkdir bundle
$ oci-image-tool create --ref latest busybox bundle/
$ ls bundle/
config.json  rootfs

It also work if docker save save serveral images.

$ docker images busybox
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
busybox             v2                  0f4cf98c1107        4 minutes ago       1.09MB
busybox             v1                  df8dde2cf4ad        4 minutes ago       1.09MB
busybox             latest              2b8fd9751c4c        13 months ago       1.09MB
$ docker save busybox | ./docker2oci busybox
$ oci-image-tool validate busybox
oci-image-tool: reference "latest": OK
oci-image-tool: reference "v1": OK
oci-image-tool: reference "v2": OK
busybox: OK
Validation succeeded