Podman-in-Podman Build

A simple replacement of redhat-actions/buildah-build, but with only podman build, and runs the command in a container with Podman image.

The newly built images are imported to Podman on the host, so this action is still compatible with actions like redhat-actions/push-to-registry.

Why?

The only Linux distro provided by GitHub-hosted runners is Ubuntu, and the latest provided version is 22.04, as of October 2023.

The installed version of Podman version is 3.4.4, and the installed version of Buildah is 1.23.1.

This could be fine for most cases, but not for ContainerUp. We tried to do a multiplatform build with a single Containerfile, but with an old buggy version of Podman and Buildah, a problem is encountered.

It's very tricky to alter the environment on the runner for a new version of Podman and Buildah. So we decided to do the build in a Podman-in-Podman container.

What does this action do?

1. Create a container with Podman image

The user is set to podman.

A temporary directory ${RUNNER_TEMP}/podman-in-podman-build is created, and the mode is set to 777.

The current working directory, ${RUNNER_TEMP}/podman-in-podman-build are mounted in the container.

The device /dev/fuse is also mounted, for the Podman in the container to run correctly.

The container is named podmaninpodman.

2. Run build commands in the container

podman exec podmaninpodman podman build ...

3. Export the newly built images

podman exec podmaninpodman save -o xxxx.tar IMAGE

4. Import the images to Podman on the host

podman load -i xxxx.tar

5. Clean up

Remove the podmaninpodman container.

Fix the ownership of files in ${RUNNER_TEMP}/podman-in-podman-build, otherwise it cannot be removed automatically as stated here.

Usage

- name: Podman-in-Podman Build
  uses: ContainerUp/podman-in-podman-build@v1
  with:
    # Relative path under $GITHUB_WORKSPACE to build the image
    # Defaults: $GITHUB_WORKSPACE
    workdir: ''

    # Path of Containerfile
    # Default: 'Containerfile'
    containerfile: ''

    # Build container images with the specified OS/ARCH
    # Separate values into multiple lines
    # Defaults to the value of the runner, e.g. linux/amd64
    platforms: ''

    # The repository:tag of Podman to be run in the container
    # Default: 'quay.io/containers/podman:latest'
    podman-image: ''

    # Required
    # The built image will be tagged as <repository>:<tags[0]>, <repository>:<tags[1]>, ...
    repository: ''

    # Refer to `repository`
    # Separate values into multiple lines
    # Default: 'latest'
    tags: ''

    # List of argument=value to supply to the builder
    # Separate values into multiple lines
    build-args: ''

    # Set metadata for an image
    # Separate values into multiple lines
    labels: ''

    # Cache the Podman image, and load the image from cache
    # Default: 'true'
    cache-podman-image: ''