Multi-arch image build Task

Goal

OpenShift supports multi-architecture compute which allows to have nodes with different architectures (e.g. x86 and Arm) as part of a single OpenShift cluster:
OpenShift Docs - configuring multi-architecture compute machines

As a developer on a multi-arch OpenShift cluster, I want an image build Task that I can use to build my application for multiple architectures that are available in the OpenShift cluster, so that my application image can get deployed into any of the nodes in the cluster.

Acceptance Criteria

• A Task exists in the catalog for building images from Dockerfile for a list of target architecture
• Tasks exist in the catalog for building images from source for a list of target architectures
• Manifests lists are updated appropriately with output images for each specified architecture
• Examples available for building images for multiple architectures in a pipeline

Notes

• Cross-compiling is not supported on RHEL and compiling for each architecture should be performed natively on a host with that architecture
• The matrix feature in TaskRuns/PipelineRuns could possibly be used but it currently lacks the ability to dynamically set nodeSelectors for the generated TaskRuns which is needed for multi-arch image builds.

Previous Work

• Building and Publishing Multi-Arch Images and Image Manifests with Red Hat Buildah and Podman
• Shipwright multi-arch build strategy