Changes/Layered Docker Image Build Service

Layered Docker Image Build Service

Summary

Fedora currently ships a Docker base image, but Docker supports a layering concept. There are some applications like Cockpit which we would like to ship as layered applications.

This change will deploy the [[1]] build service to support building and delivering a set of layered Docker images.

Owners

• Name: Colin Walters
• Name: Adam Miller

• Release notes owner:

Current status

• Targeted release: Fedora 23
• Last updated: 2015-06-17
• Tracker bug:

Detailed Description

The system has four major parts:

• A command-line client — already integrated into rpkg; needs only minor work to enable in fedpkg
• dist-git for Dockerfiles
• A koji plugin, containerbuild
• An OpenShift 3 backend

For more information, see this presentation for the high level information of the whole system.

Benefit to Fedora

What is the benefit to the platform?

Docker is a very popular way to deliver container images. This will help deliver Fedora-based containers inside the Docker ecosystem, and other applications that are part of the Fedora package collection as containers.

Fedora Server is planning to deliver Server Roles as containers; this will facilitate that. And vital parts of Fedora Atomic are now designed to be delivered in containers, but we currently have no mechanism to do that within Fedora itself.

Scope

• Proposal owners: Proposal owners shall have to
  • Deploy OSBS
    • Deploy OpenShift v3
    • Deploy container build koji plugin (optional)
  • create dist-git for Dockerfiles

• Other developers:
  • Possible integration with Bodhi for releasing updated images

• Release engineering:
  • Deploy OSBS

• Policies and guidelines:
  • Need to determine who can submit/build images
  • Determine who is responsible for building/testing images as RPMs change
  • Determine policy for non-RPM content
  • "Packaging guidelines" for Dockerfiles; suggest starting lightweight and building as needed. Project Atomic documentation can be a starting point.

Out of Scope

Registry

This Change does not include running a Fedora container registry. Although we might want to do so in the future, this should not be a blocker. Container images will be a) delivered to the upstream Docker Hub and b) put on the Fedora FTP/HTTP mirror network.

Other Integrations

In the future, images could be integrated into Bodhi, just like RPMs.

It would also be nice to have a pkgdb interface, but that shouldn't be a blocker.

Upgrade/compatibility impact

Since the world of containers is changing rapidly, it is possible that the system might need to be upgraded in future to latest stable version.

How To Test

Ideally, we have a Fedora registry. If so, then adding it and doing:

atomic run registry.fedoraproject.org/cockpit

User Experience

There's many potential roles interacting here - the container owner, the container user, release engineering.

Dependencies

• N/A

Contingency Plan

People continue to upload to the Docker Hub in an ad-hoc fashion with no integration with Fedora.

Documentation

Needs filling in.