Release procedure#

This page gives an overview of how Nublado releases are made. This information is only useful for maintainers.

Nublado’s releases are largely automated through GitHub Actions (see the ci.yaml workflow file for details). When a semantic version tag is pushed to GitHub, Nublado Docker images are published on GitHub with that version.

Regular releases#

Regular releases happen from the main branch after changes have been merged. From the main branch you can release a new major version (X.0.0), a new minor version of the current major version (X.Y.0), or a new patch of the current major-minor version (X.Y.Z). See Backport releases to patch an earlier major-minor version.

Release tags are semantic version identifiers following the PEP 440 specification.

1. Update the change log#

Change log messages for each release are accumulated using scriv (see Updating the change log). When it comes time to make the release, there should be a collection of change log fragments in changelog.d. Those fragments will make up the change log for the new release.

Review those fragments to determine the version number of the next release. Nublado follows semver, so follow its rules to pick the next version:

  • If there are any backward-incompatible changes, incremeent the major version number and set the other numbers to 0.

  • If there are any new features, increment the minor version number and set the patch version to 0.

  • Otherwise, increment the patch version number.

Then, run scriv collect --version <version> specifying the version number you decided on. This will delete the fragment files and collect them into CHANGELOG.md under an entry for the new release. Review that entry and edit it as needed (proofread, change the order to put more important things first, etc.).

Finally, create a PR from those changes and merge it before continuing with the release process.

2. Tag the release#

At the HEAD of the main branch, create and push a tag with the semantic version:

git tag -s X.Y.Z -m "X.Y.Z"
git push --tags

The tag must follow the PEP 440 specification since Nublado uses setuptools_scm to set version metadata based on Git tags. In particular, don’t prefix the tag with v.

The ci.yaml GitHub Actions workflow uploads the new release to Docker Hub.

3. Create a GitHub release#

Add a new GitHub release for this version. The release title should be the same as the version number.

Then, above that, paste the contents of the CHANGELOG.md entry for this release, without the initial heading specifying the version number and date. Adjust the heading depth of the subsections to use ## instead of ### to match the pull request summary.

Then, press the Generate release notes button to include the GitHub-generated summary of pull requests.

4. Update Phalanx#

In the Phalanx repository under applications/nublado, update the values.yaml and values-environment.yaml files for any changes in Nublado’s configuration.

Then, as part of the same PR, update the version in applications/nublado/Chart.yaml to the latest release tag. Also update the setting jupyterhub.hub.image.tag to the same value. Finally, find any reference to the nublado-inithome container in the per-environment values-environment.yaml files and update its version number to the same value.

Test the new version on a development cluster using the instructions in the Phalanx documentation before merging.

Backport releases#

The regular release procedure works from the main line of development on the main Git branch. To create a release that patches an earlier major or minor version, you need to release from a release branch.

Creating a release branch#

Release branches are named after the major and minor components of the version string: X.Y. If the release branch doesn’t already exist, check out the latest patch for that major-minor version:

git checkout X.Y.Z
git checkout -b X.Y
git push -u

Developing on a release branch#

Once a release branch exists, it becomes the “main” branch for patches of that major-minor version. Pull requests should be based on, and merged into, the release branch.

If the development on the release branch is a backport of commits on the main branch, use git cherry-pick to copy those commits into a new pull request against the release branch.

Releasing from a release branch#

Releases from a release branch are equivalent to regular releases, except that the release branch takes the role of the main branch.