buildah-build

Buildah Build is a GitHub Action for building Docker and Kubernetes-compatible images quickly and easily.

Buildah only works on Linux. GitHub's Ubuntu Environments (ubuntu-18.04 and newer) come with buildah installed. If you are not using these environments, or if you want to use a different version, you must first install buildah.

After building your image, use push-to-registry to push the image and make it pullable.

Action Inputs

Inputs for build from containerfile

Input Name	Description	Default
archs	Label the image with this architecture, instead of defaulting to the host architecture. Refer to Multi arch builds for more information. For multiple architectures, seperate them by a comma	None (host architecture)
platforms	Label the image with this platform, instead of defaulting to the host platform. Refer to Multi arch builds for more information. For multiple platforms, seperate them by a comma	None (host platform)
build-args	Build arguments to pass to the Docker build using --build-arg, if using a Containerfile that requires ARGs. Use the form arg_name=arg_value, and separate arguments with newlines.	None
context	Path to directory to use as the build context.	.
containerfiles*	The list of Containerfile paths to perform a build using docker instructions. Separate filenames by newline.	Required
extra-args	Extra args to be passed to buildah bud. Separate arguments by newline. Do not use quotes.	None
image	Name to give to the output image. Refer to the Image and Tag Inputs section.	Required - unless all tags include image name
layers	Set to true to cache intermediate layers during the build process.	None
oci	Build the image using the OCI metadata format, instead of the Docker format.	false
tags	One or more tags to give the new image. Separate by whitespace. Refer to the Image and Tag Inputs section.	latest
labels	One or more labels to give the new image. Separate by newline.	None
tls-verify	Require HTTPS and verify certificates when accessing the registry. Set to false to skip the verification	true

* The containerfiles input was previously dockerfiles. Refer to this issue.

Inputs for build without containerfile

Input Name	Description	Default
archs	Label the image with this architecture, instead of defaulting to the host architecture. Refer to Multi arch builds for more information. For multiple architectures, seperate them by a comma	None (host architecture)
base-image	The base image to use for the container.	Required
content	Paths to files or directories to copy inside the container to create the file image. This is a multiline input to allow you to copy multiple files/directories.	None
entrypoint	The entry point to set for the container. Separate arguments by newline.	None
envs	The environment variables to be set when running the container. Separate key=value pairs by newline.	None
image	Name to give to the output image. Refer to the Image and Tag Inputs section.	Required - unless all tags include image name
oci	Build the image using the OCI metadata format, instead of the Docker format.	false
port	The port to expose when running the container.	None
tags	One or more tags to give the new image. Separate by whitespace. Refer to the Image and Tag Inputs section.	latest
labels	One or more labels to give the new image. Separate by newline.	None
workdir	The working directory to use within the container.	None
extra-args	Extra args to be passed to buildah from. Separate arguments by newline. Do not use quotes.	None
tls-verify	Require HTTPS and verify certificates when accessing the registry. Set to false to skip the verification. This will be used with buildah from command.	true

Image and Tags Inputs

The image and tags inputs can be provided in one of two forms.

At least one tag must always be provided in tags. Multiple tags are separated by whitespace.

Option 1: Provide both image and tags inputs. The image will be built, and then tagged in the form ${image}:${tag} for each tag.

For example:

image: quay.io/my-namespace/my-image
tags: v1 v1.0.0

will create the image and apply two tags: quay.io/my-namespace/my-image:v1 and quay.io/my-namespace/my-image:v1.0.0.

Option 2: Provide only the tags input, including the image name in each tag. The image will be built, and then tagged with each tag. In this case, the image input is ignored.

For example:

# 'image' input is not set
tags: quay.io/my-namespace/my-image:v1 quay.io/my-namespace/my-image:v1.0.0

will also apply two tags: quay.io/my-namespace/my-image:v1 and quay.io/my-namespace/my-image:v1.0.0.

If the tags input does not have image names in the ${name}:${tag} form, then the image input must be set.

Action Outputs

image: The name of the image as it was input.
tags: A space-separated list of the tags that were applied to the new image.
image-with-tag: The name of the image, tagged with the first tag.

For example:

image: "spring-image"
tags: "latest ${{ github.sha }}"
image-with-tag: "spring-image:latest"

Build Types

You can configure the buildah action to build your image using one or more Containerfiles, or none at all.

Building using Containerfiles

If you have been building your images with an existing Containerfile, buildah can reuse your Containerfile.

In this case the inputs needed are image and containerfiles. tag is also recommended. If your Containerfile requires ARGs, these can be passed using build-arg.

name: Build Image using Containerfile
on: [push]

jobs:
  build:
    name: Build image
    runs-on: ubuntu-latest

    steps:
    - uses: actions/checkout@v4

    - name: Buildah Action
      uses: redhat-actions/buildah-build@v2
      with:
        image: my-new-image
        tags: v1 ${{ github.sha }}
        containerfiles: |
          ./Containerfile
        build-args: |
          some_arg=some_value

Building without a Containerfile

Building without a Containerfile requires additional inputs, that would normally be specified in the Containerfile.

Do not set containerfiles if you are doing a build from scratch. Otherwise those Containerfiles will be used, and the inputs below will be ignored.

• An output image name and usually a tag.
• base-image
  • In a Containerfile, this would be the FROM directive.
• content to copy into the new image
  • In a Containerfile, this would be COPY directives.
• entrypoint so the container knows what command to run.
  • In a Containerfile, this would be the ENTRYPOINT.
• All other optional configuration inputs, such as port, envs, and workdir.

Example of building a Spring Boot Java app image:

name: Build Image
on: [push]

jobs:
  build-image:
    name: Build image without Containerfile
    runs-on: ubuntu-latest

    steps:
    - uses: actions/checkout@v4

    - run: mvn package

    - name: Build Image
      uses: redhat-actions/buildah-build@v2
      with:
        base-image: docker.io/fabric8/java-alpine-openjdk11-jre
        image: my-new-image
        tags: v1
        content: |
          target/spring-petclinic-2.3.0.BUILD-SNAPSHOT.jar
        entrypoint: java -jar spring-petclinic-2.3.0.BUILD-SNAPSHOT.jar
        port: 8080

Multi arch builds

Refer to the multi-arch example.

Emulating RUN instructions

Cross-architecture builds from containerfiles containing RUN instructions require qemu-user-static emulation registered in the Linux kernel.

For example, run sudo apt install qemu-user-static on Debian hosts, or sudo dnf install qemu-user-static on Fedora.

You can run a containerized version of the registration if the package does not exist for your distribution:

sudo podman run --rm --privileged docker.io/tonistiigi/binfmt --install all

This registration remains active until the host reboots.

The archs and platforms inputs

The archs and platforms arguments override the Architecture and Platform labels in the output image, respectively. They do not actually affect the architectures and platforms the output image will run on. The image must still be built for the required architecture or platform.

There is a simple example in this issue.

Creating a Multi-Arch Image List

Input archs and platforms is provided to build the multi architecture images. If one of these input is provided with the multiple archs or platforms then a manifest is built with the multiple architecture images. Name of the manifest is taken from the inputs image and tags. Incase multiple tags are provided then multiple manifest is created based on the provided tags.

Use the archs and platforms inputs to build multi-architecture images. The name of the manifest is determined by the image and tags inputs.

If multiple tags are provided, multiple equivalent manifests will be created with the given tags.

push-to-registry action can be used to push the generated image manifest.

Build with docker/metadata-action

Refer to the docker/metadata-action example.

Using private images

If your build references a private image, run podman-login in a step before this action so you can pull the image. For example:

- name: Log in to Red Hat Registry
  uses: redhat-actions/podman-login@v1
  with:
    registry: registry.redhat.io
    username: ${{ secrets.REGISTRY_REDHAT_IO_USER }}
    password: ${{ secrets.REGISTRY_REDHAT_IO_PASSWORD }}