Elemental Channels

Elemental Channels can be used to publish a list of container images to be used by the Elemental Operator.

This repository automates and facilitates the creation of the officially distributed Elemental channels.

Goals for this repository

1. Be the single source of truth for all channel .json files that need to be published by the Elemental team
2. Automatically refresh the channels watching container registries (Daily)
3. Automatically generate a tarball per channel including a .packages file per image listing all the packages that are part of the image
4. (Optional) Publish images on GitHub, for development or testing

Repository Watches config

The config.yaml can be updated using the following structure:

watches: 
    # A flavor for the Base OS being watched. Can be "" for unflavored images.
    # This will be used as a prefix to distinguish same versions of different flavors.
  - flavor: "my-flavor"
    # The resulting .json filename on the ./channels directory
    fileName: "sle-micro-5-5-my-flavor"
    # The OS human readable name
    displayName: "SLE Micro 5.5 My Flavor"
    # The repository containing the "os" type images
    osRepo: registry.suse.com/suse/sle-micro/my-flavor-5.5
    # The repository containing the "iso" type images.
    # If this is not applicable, use "N/A"
    isoRepo: registry.suse.com/suse/sle-micro-iso/my-flavor-5.5
    # How many images to limit per (minor) version.
    limit: 3
    # The minimum version to start listing the channel. Usefull to skip any
    # pre GM build that eventually got released to the registry during release preparation.
    minVersion: 2.2.0

Usage

It is possible, at any moment, to run the .refresh_channels.sh script and integrate the changes, if any.
A GitHub workflow does it automatically every night, and optionally it can be triggered at any time.

.refresh_channels.sh script will recreate the .json file of a channel and the associated .packages.tar file.

Manually crated .json files can be directly created and maintained in the ./channels directory, for example to maintain a channel containing arbitrary images, for development or testing.
When this is the case, be mindful of not creating collision with the automated config.yaml, otherwise files with the same name will be overwritten.

Unstable channel

The unstable or development channel is a special static one that is meant to include latest build of the development OBS projects. Hence this is an static JSON only including the ISO and OS container for the current build in projects under or branched from isv:Rancher:Elemental in OBS. This channel is not automated or generated by any kind of continuous integration.

Elemental channel images

The Elemental channel images are defined under .obs/dockerfile/elemental-channel-image. This folder is actually used to feed rancher/elemental-obs repository which includes the OBS sources for all Elemental components.

Changelog generation for images listed in channels

1. Changelogs are precomputed and generated at build time, as part of the Dockerfile, only if the updatesinfo.xml files are present.
2. The updatesinfo.xml file is parsed and computed using the updatesparser utility included in this git repository.
3. There is a single changelog file in JSON format per image listed within the channel.
4. Each change log file includes the updates up to its creation date and after the creation date of the previous image. Oldest image in the list includes all the updates up to its creation date.
5. Changelogs are included within the channel image in /changelogs folder. Each file is named with the name of the imge it relates to (aka the ManagedOSVersion name) with the .updates.log extension.
6. Within the image sources there is the needed script to checkout the updateinfo.xml files at OBS commit time and the script to eventually iterate over the images listed in channels and precompute the changelog per image at build time.

Channels update sequence

The semi automated process to generate and update channels including chanegelogs is essentially the following:

1. Within the current repository the .refresh_channels.sh script is used in GHA or manually to recreate the channel .json files and the *.packages.tar files. GHA creates automatic PRs, merging them is a manual process.
2. In rancher/elemental-obs GHA there is job to keep track of latest changes in this repository and update elemental-channel-image OBS package accordingly. Creates automatic PRs, merging them is a manual process.
3. To include updatesinfo.xml files in OBS a manual process is required. Call the update.sh script on a local checkout with the appropriate product URL, this will download the updatesinfo.xml files which can then be committed as part of the sources.