Optimized pipeline for Buildah

[computeralex92]

Hello all,

I'm currently implementing a buildah-based pipeline to switch midterm from Kaniko to Buildah (one reason is multi-arch images).
Since the Kaniko pipeline is super optimized for speed, I want to implementing a similar solution for Buildah.

My current setup for Kaniko:

/kaniko/warmer
--cache-dir=/cache
--image="$GITLAB_IMAGE_NAME:latest"
--image="$GITLAB_IMAGE_NAME:$CI_COMMIT_REF_SLUG"
--image="$GITLAB_IMAGE_NAME:$CI_DEFAULT_BRANCH"
--image="$GITLAB_IMAGE_NAME:$IMAGE_TAG"
|| true
/kaniko/executor
--cache=true
--cache-dir=/cache
--context $DOCKER_CONTEXT
--dockerfile $DOCKER_CONTEXT/$DOCKERFILE_NAME
--destination "$GITLAB_IMAGE_NAME:$IMAGE_TAG"

My current Buildah setup is working, but sometimes in compare to Kaniko quite slow:

buildah pull --platform=${BUILD_PLATFORM} "$GITLAB_IMAGE_NAME:$CI_COMMIT_REF_SLUG" || true
buildah pull --platform=${BUILD_PLATFORM} "$GITLAB_IMAGE_NAME:$CI_DEFAULT_BRANCH" || true
buildah pull --platform=${BUILD_PLATFORM} "$GITLAB_IMAGE_NAME:$IMAGE_TAG" || true
buildah pull --platform=${BUILD_PLATFORM} "$GITLAB_IMAGE_NAME:latest" || true
buildah build
--jobs=2
--cache-from=$GITLAB_IMAGE_NAME/cache
--cache-to=$GITLAB_IMAGE_NAME/cache
--layers
--format=docker
--platform=${BUILD_PLATFORM}
--manifest="$GITLAB_IMAGE_NAME:$CI_JOB_ID"
.

buildah manifest push
--all
--format=v2s2
"$GITLAB_IMAGE_NAME:$CI_JOB_ID"
docker://"$GITLAB_IMAGE_NAME:$IMAGE_TAG"

I see partly that in special the caching via cache-from and cache-to is working.
Maybe some of you also had this challenge and have some ideas how to optimize my pipeline; as I'm still working on it, I will update my implementation when I change something.

Thanks a lot,
Alex