SQR-016: Stack release playbook

  • Frossie Economou

Latest Revision: 2018-07-11

Note

This technote is not yet published.

SQuaRE instructions for making official releases

1   The LSST Stack Release Process

The LSST stack is a large mixed Python/C++ codebase split among many repos with multiple dependencies between them built by a niche build system. The release process is therefore a bit complex and can be protracted. In an attempt not to have to co-ordinate the state of the release with 80+ developers, or worse, have them down tools while a release is being minted, this process has been optimized to impact development as little as possible. Unless a developer needs to be called upon to fix a failing integration or platform test, she can carry on as normal.

In gross, the conceptual steps are:

  1. A successful weekly release is identified that forms the basis for the official release.
  2. The first release candidate (rc1) is tagged using that weekly as a seed. This means that it does not matter if the codebase’s master has moved on in the meanwhile.
  3. Repositories are tagged or branched with additional rc tags if hotfixes or late features are accepted
  4. Documentation is updated on a branch (release notes, installation instructions, metrics report)
  5. The final build is published and the documentation merged to master.

2   Kicking-off the process

The first step is to establish whether it is a good time to make a release, eg. if many developers are about to push significant features, it may be better to wait for them to finish. Announce the intent to make a release in the #dm channel and inform all DM T/CAMs and the DM System Engineer.

If it is generally a good time, identify the nearest weekly release, this will be the seed for the release candidate.

Next, start a community.lsst.org post to use for status updates.

3   Preparing for a candidate release

3.1   Get codekit installed

The release manager can folow the instructions at:

https://github.com/lsst-sqre/sqre-codekit

If you are working interactively you want to set the environment variable DM_SQUARE_DEBUG to 1 as it gives more insight on what is going on with the Github REST API calls.

3.2   Github teams

There are three “special” teams in the LSST Github org

These are:

  • Data Management
  • DM Externals
  • DM Auxilliaries

These are used in the release process in the following way:

Data Management repos that are a dependency of lsst_distrib are tagged with the bare release version, eg. 14.0 DM Externals that are a dependency of lsst_distrib are tagged with v14.0 (so that eups does not show it and confuse people who want the upstream semantic versioning to show up) DM Auxilliaries are repos that we want to snapshot as part of a relase (eg sdss_demo) but are not an eups dependancy of lsst_distrib.

3.3   Release the demo

Go to https://github.com/lsst/lsst_dm_stack_demo/releases and ‘Draft a new release’ with your tag. See its release history for examples.

3.4   Branching the docs

At this point you should branch lsst/pipelines_lsst_io

git clone https://github.com/lsst/pipelines_lsst_io.git
git checkout -b 14.0

Update the demo.rst page to point to the demo release you just made and use this version for testing your candidates as described in the pipelines documentation for testing your installation.

4   Candidate release

Identify the weekly you wish to build the release on, say w_2017_33.

Look into the text of the annotated tag (using git log or the Github UI) to see what the bXXXX number was.

4.1   Tag the candidate

Tagging first and third parties allows the release to be reproduceable in the future and is necessary for the final build process.

Note the difference in tag name convention between first and third parties.

# git tag the first parties

github-tag-version --org lsst --team 'Data Management' --candidate v14_0_rc2 14.0 bXXXX
github-tag-version --org lsst --team 'Database' --candidate v14_0_rc2 14.0 bXXXX

# for externals NOTE THE v PREFIX to avoid stomping on the eups semantic versioning
github-tag-version --org lsst --team 'DM Externals' --candidate v14_0_rc2 v14.0 bXXXX

This is the final tag against the third parties since they are slow-moving and have been proven to work with the weekly candidate seed. In the rare event where a problem is identified the tag can be moved along.

4.2   Publish the candidate

5   Final source release

5.1   Branching lsst

In this process we make use of the fact that git doesn’t care whether a ref is a tag or a branch to constrain the number of branches to repositories that need retroactive maintainance or need to be available in more than one cadence. One such example is the lsst repo since it containes newinstall.sh which sets the version of eups, and that may be different for an official release than the current bleed.

The first repo that should be branched is lsst/lsst:

git clone https://github.com/lsst/lsst.git
git checkout -b 14.0

Now in lsst/scripts/newinstall.sh change the canonical reference for this newinstall to be one associated with the current branch:

NEWINSTALL="https://raw.githubusercontent.com/lsst/lsst/14.0/scripts/newinstall.sh"

and commit and push.

This means that if you need to update newinstall.sh for bleed users, official-release users will not be prompted to update to the latest version, but will phone home against their official-release branch for hotfixes.

Also double-check for other things that might need to be updated, like the documentation links (though these should really be fixed on master prior to branching or cherry-picked back).

5.2   Doc update: newinstall.rst

Update the newinstall.rst page on your release branch of pipelines_lsst_io with the new download location of the newinstall.sh script.

5.3   Final tag

Now it’s time to lay down the final git tag. For repositories that have already been branched with the 14.0 ref, that will fail, which is fine.

This is mostly a repeat of the process for laying down the candidate tag but this time we use numeric tags so that eups will see them:

# tag repos involved in the final candidate and final build
github-tag-version --org lsst --team 'Data Management' --candidate v14_0_rc2 14.0 b3176
github-tag-version --org lsst --team 'Database' --candidate v14_0_rc2 14.0 b3176

Since you already tagged the third parties with their special final tag already, no need to do anything here.

5.4   Release build

  • Submit the run-rebuild job with your parameters (eg. 14.0 v14.0)
  • At this point you should not be seeing master-g type references as eups versions. Everything should have a tag-derviced version such as 14.0 if they are a DM repo and their semantic tag (eg. pyfits 3.0) if they are external. If you see one, you need to chase down why. The only situation that should happen is if a third party but a branch is used for LSST development that lacks any other type of semantic versioning (in the 14.0 release this included starlink_ast and jointcal_cholmod.
  • Note your final bNNNN number for the publish (either from the build log or by looking at the next of the annotated 14.0 tag on any repo eg. afw).
  • Submit the run-publish job making sure you have selected package and not git as the option.

5.5   Other OS checking

While we only officially support the software on certain platforms (RHEL/CentOS 7 is the reference, and we CI MacOS and RHEL 6), we check in a number of other popular platforms (eg Ubuntu, newer versions of CentOS etc) by spinning up machines on Digital Ocean (typically) and following the user install instructions. This also allows us to check the user from-scratch installation instructions including the pre-requisites.

6   Binaries

Run the tarball-matrix job with the options SMOKE, RUN_SCONS_CHECK, PUBLISH.

7   Documentation

Documentation to be collected for the release notes in pipelines_lsst_io is:

  • Release notes from the T/CAMs for Pipelines, SUI, and DAX
  • Characterisation report from the DM or SQuaRE scientist
  • Known issues and pre-requisites from the T/CAM for SQuaRE
  • Before merging to master, ask the Documentation Engineer to review

8   c.l.o stubb

Here is where we currently are in the release process. Current step in bold.

Summary
-----------

Release is complete

Precursor Steps
---------------------------------

1. Identify any pre-release blockers ("must-have features") :tools:
2. Wait for them to clear


Release Engineering Steps
-------------------------------

1. Eups publish rc1 candidate (based on b2748) (also w_2017_33)
1. Git Tag v14.0-rc1
1. Branch v14 of newinstall.sh
1. Github release lsst_demo v14
1. **Wait for first round of bugs to clear**
1.Repeat last 2 steps, -rcN candidates  <-- final candidate is rc1 [yay!]
1. Confirm DM Externals are at stable tags
1. Tag DM Auxilliary (non-lsst_distrib) repos
1. Full OS testing (see https://ls.st/faq )
1. Git Tag 14.0, rebuild, eups publish

Binary release steps
------------------------

1. Produce factory binaries
1. Test factory binaries
1. Gather contributed binaries

Documentation Steps
-------------------------

1. Update Prereqs/Install
1. Update Known Issues
1. Gather Release notes
1. Gather Metrics report
1. **Email announcement**

9   Format of “tags”

9.1   git tags

  • DM produced code this is part of an “official” release must have a git tag that starts with a number
  • “official” release git tags on external/third-party software that DM has repackaged must be prefixed with a v but are otherwise identical to that on DM produced code. Eg., 42.0.0 -> v42.0.0
  • Non-“official” releases, release candidates, weekly builds, etc. must start with a letter
  • shall only use [a-z], [0-9], and .
    • lowercase latin alphabet characters shall be used; uppercase characters are forbidden
    • These common characters must not be used: -, _, /

Examples of valid (good) git tags

# unofficial builds
d.2038.01.19
w.2038.03

# release candidate
v42.0.0.rc99

# official release of DM produced code
42.0.0

# official release of external/third-party product
v42.0.0

Examples of invalid (bad) git tags

d_2038_01_19
w_2038_03
v42-0-0-rc99
42_0_0
v42_0_0
foo/bar

9.2   eups tags

  • must not start with a numeric value
  • shall only use [a-z], [0-9], and _
    • lowercase latin alphabet characters shall be used; uppercase characters are forbidden
    • EUPS reportedly has or has had problems with . and -
  • official releases and release candidates must be prefixed with v

Examples of valid (good) eups tags

# unofficial builds
d_2038_01_19
w_2038_03

# release candidate
v42_0_0_rc99

# official release of DM produced code AND external/third-party product
v42_0_0

Examples of invalid (bad) eup tags

123
d.2038.01.19
w.2038.03
v42_0_0-rc99
42.0.0
v42.0.0
foo/bar

9.3   git <-> eups tag conversion

The “tags” along each row in the following table should be considered equivalent conversions.

internal git external git eups tag
d.2038.01.19 d.2038.01.19 d_2038_01_19
w.2038.03 w.2038.03 w_2038_03
v42.0.0.rc99 v42.0.0.rc99 v42_0_0_rc99
42.0.0 v42.0.0 v42_0_0