Shift guide for release coordinators

Last update: 05 Aug 2022 [History] [Edit]

Introduction

This page contains information about the workflows and procedures a release coordinator is concerned with. It is assumed that you are familiar with the general workflow for ATLAS Offline software development as summarised in the Workflow Quick Reference. Having an overview of the tasks of the software review shifters as well as knowing basics of git is also helpful.

Checking the status of the release

Before accepting new MRs, you should check the status of the latest nightly. The first priority of a release coordinator should be to make sure that the release is in good shape, and obviously existing problems should usually be fixed before adding more MRs (though as release coordinator you should always feel free to use your judgement).

How to check the nightly build status?

The status of the nightly builds can be checked in two places:

The latter contains information on ART build jobs and other detailed information for the different build steps. Information on the nightly (and CI) build infrastructure are available on this twiki page.

For each nightly build check:

  1. All unit tests succeed. If there are failures, try to identify the responsible MR and post a comment on it. If you cannot identify any MR, open a Jira ticket in the relevant Jira tracker.
  2. No new failures in the ART build tests.
  3. Check the ART grid tests to see which tests are running / failing. It can happen that a MR has broken some tests because they aren’t part of the CI tests (the CI is necessarily a subset of all of the possible tests).

Any problem seen in the unit tests will very likely also affect the CI jobs. To help the review shifters please mark any relevant Jira tickets with the “CI” label. This will make the issue appear on the CI Status Board.

What to do if nightly is not yet available on cvmfs?

First check on Jenkins if the nightly finished or it is still ongoing. If it is still ongoing and it is already afternoon check that it is not stuck on something. Just by checking the console log file should give you a good idea if the nightly is progressing (select the nightly you are interested in and then click on the “Console” icon).

If the nightly finished and the status of the build is a Blue ball - the nightly should be available on CVMFS.

If the nightly finished and the Status is Red ball - the build failed for some reason. Now you need to identify the exact reason. Every nightly is executing the following steps so while investigating check the steps one by one and see where there is a problem:

  • git clone
  • building externals
  • building the main project
  • creating the RPMs
  • preparing the RPMs and copying them to EOS – once done the RPMs should be visible under http://atlas-software-dist-eos.web.cern.ch/atlas-software-dist-eos/RPMs/nightlies/
  • installation on CVMFS (in the Console log at the end there will be a line like 
    The logfile is copied under: /cvmfs/atlas-nightlies.cern.ch/repo/sw/master/2018-07-15T2059/master__Athena__x86_64-slc6-gcc62-dbg__2018-07-15T2059__1531720274.ayum.log

    All the information can be found inside the “Console” log file for the given nightly.

WarningNote that issues with git and copying the RPMs to EOS are IT infrastructure related issues. If there were git problems you can restart the nightly. If there were RPM to EOS copy problems check with Atlas.Release to redo the copy.

Handling new merge requests

Finding open merge requests for your release

In git, different releases are represented by different branches of the atlas/athena git repository. One subtle point is that what code we build from the branch is controlled by the project specific scripts that live in the Projects directory of the branch (e.g., here for the master branch). You are, however, the release coordinator for all projects built from a branch.

Upon creation, merge requests will be tagged automatically by the CI system with a label indicating their target branch. In addition, the CI system also adds a label indicating the stage and result of the software review process. Changes approved by the software review shifters are labeled as review-approved. Therefore, you should be able to select all ready-to-be-accepted merge requests from the GitLab merge request overview page. Simply filter the list of merge requests by selecting review-approved and your release branch name from the dropdown menu for labels.

Full rebuilds need to be triggered after updates where an incremental rebuild may not catch all changes properly, such as a LCG version update. Such updates should be performed in late evenings, with advance notification emailed to ATLAS robot to provide CI system administrators enough time to schedule cleaning local disks of build machines (to ensure builds are from scratch).

The CI job state is depicted by a small icon on the right (e.g. green checkmark for passed, red cross for failed, blue circle for running). This status sometimes does not get updated correctly (e.g. a CI job is indicated as still running while it has already finished). Therefore, please do not rely on this icon. If in doubt, check the discussion tab of this MR for the latest CI summary comment from the ATLAS robot.

Accepting merge requests

Before accepting any merge request, please have a quick look at the description and the discussion on GitLab merge request page. They may contain some more detailed information about the nature of this merge request and possibly also the relation with other merge requests (e.g. dependencies between MRs). You should also make sure that all discussions were resolved.

Once you are sure that you want to merge these changes into your release, you can accept the merge request by pushing the green “Merge” button.

WarningPlease do not use the command line merging procedure as described on GitLab.

Due to the fact that updates of the CI pipeline status has been found unreliable in the past, release coordinators are discouraged from using the “Merge When Pipeline Succeeds” feature.

How to roll back bad merges?

If you want to undo the changes introduced by an (already accepted) merge request, you have to go the GitLab webpage for this merge request. There is an orange button labeled Revert. Clicking on this button opens a new dialog where you should choose the target branch to be the same as the target branch of the initial merge request. Please leave the checkbox “Open a new merge request” checked. Confirm the settings by clicking on the green Revert button. This will open a new merge request undoing the changes introduced by the faulty merge request and the usual CI jobs and the review process start automatically.

Tag and deploy a release after a successful build

Once you are satisfied as the release coordinator that a nightly release is good enough to be deployed to the production CVMFS server then you need to do the following steps:

Copy RPMS and Install to CVMFS

Tip See here for instructions on how to setup tunnelling using browser plugins.

  • Log in with username “jobrest”. If you do not know the password, ask Alex Undrus.

  • Click “Build with parameters” on the left hand sidebar. Fill in the details on the screen where:

    • numbered_release: 22.0.55
    • cmtconfig can be: x86_64-centos7-gcc11-opt
    • project can be: Athena, AthSimulation, AnalysisBase etc
    • Executor_Label: leave it unchanged
    • nightly_name can be: master, 22.0-mc20, 21.0 and so on
    • rel_nightly is the timestamp for your nightly, e.g. 2022-02-02-T2101
    • Then click “Build”
    • Check the console to make sure nothing has gone wrong.
    • When everything is deployed, please announce the installed release by email as indicated below.

Repeat the above steps for any other platforms you may need (e.g. the opt and dbg builds typically have slightly different timestamps).

Tag the release in git

Create a new tag for the release in the main repository. Enter the Tag name, which should always be release/A.B.X[.Y], i.e., the actual numbered release version; the Create from should be the nightly build tag that is being used, which has the format nightly/BRANCH_NAME/DATE_STAMP.

Tip In case you have built multiple platforms for the same release use the nightly stamp of the primary platform (e.g. gcc8-opt). In practice this should not matter as the nightly tags for different platforms should all point to the same git commit if started around the same time.

Then enter an informative message about the reason for deploying this particular release that will be useful to others. An example might be the following:

You should also generate the changelog using this script. The script is documented, but in brief, you run it in the athena directory and give it three parameters: the tag of the release you are building, the tag of the nightly used to build it, and your gitlab API token (see here, for instructions on how to create one). For example:

lsetup git
lsetup gitlab
git clone ssh://git@gitlab.cern.ch:7999/atlas/athena.git
cd athena
./Build/AtlasBuildScripts/prepare_release_notes.py release/22.0.82 nightly/22.0/2022-08-02T2101 -t YOUR_TOKEN_HERE
Release notes generated in 'release_notes.md'

If you do not have a gitlab API token, then you can run it without but the release notes will be less detailed (specifically the domain labels will be missing).

WarningAlways use the latest version of the script from the master branch even when building releases from other branches.

Alert You can also create the tag locally in any clone of the repository and push it to atlas/athena. It’s not recommended unless you really know what you are doing.

Update the release candidate number

Finally, now that a nightly has been promoted to a numbered release the release candidate number needs to be updated to be the next number in the release series for this branch + project. The easiest way to do this is via the “Web IDE” editor in GitLab itself. Navigate to the correct branch and project version.txt file and select “Open in Web IDE”:

In the following navigate to all version.txt files that need updating and increment the release number. Once done create a single commit on the release branch with all updates:

Alert All Projects (except AnalysisBase, AthGeneration and AthAnalysis) should be kept in sync. So if, for example, you update the version of Projects/Athena/ to 22.0.21 you should also update AthDataQuality, AthSimulation, DetCommon and VP1Light

Tip Only people with push rights to the branch can do this directly. You should have these rights as a release coordinator, otherwise you need to make a merge request.

Alternatively, you can do it entirely on the command in your local athena checkout:

git fetch upstream
git checkout upstream/BRANCH    # e.g. master, 22.0, ...
grep "" Projects/*/version.txt  # show all project versions
old=23.0.4 new=23.0.5 && git grep -l $old Projects/*/version.txt | xargs sed -i s/$old/$new/
git diff                        # verify the changes
git commit -a -m "Bump project versions to $new"
git push upstream

Announce the release by email

After the release has been built, please announce the release by sending out an email:

mailto: atlas-sw-spmb@cern.ch, hn-atlas-recoIntegration@cern.ch, atlas-dp-proc@cern.ch, atlas-trigger-operation@cern.ch, hn-atlas-releaseKitAnnounce@cern.ch
subject: Release Athena,22.0.42 

Dear all,

This is to let you know that the release Athena,22.0.42 has been built from the nightly
Athena,master,2021-08-23T2101 and is in the process of being distributed to CVMFS.

The JIRA ticket can be found here:
https://its.cern.ch/jira/browse/ATLINFR-4208

The release notes are available at:
https://gitlab.cern.ch/atlas/athena/-/releases/release%252F22.0.42

Regards, myName

Manual merge of release branches

As of writing, changes to the 22.0 release branch are manually merged (~daily) into master by the master release coordinator. To avoid having to manually resolve known conflicts (e.g. version.txt files) each time, we use a custom merge driver.

The “driver” called “ours” needs to be setup once in the user’s ~/.gitconfig file:

git config --global merge.ours.driver true

The true is the shell-builtin that does nothing, i.e. no actions will be taken for files that use the “ours” merge driver. The configuration of the merge driver is done via gitattributes. Since we do not want to impose these drivers on all users, they are kept in a separate file SweepRule/attributes in the repository and enabled on a per-command basis:

# in your atlas/athena clone:
git fetch upstream
git checkout -b "sweep_22.0_master_`date +%Y-%m-%d`" upstream/master
git -c core.attributesFile=SweepRule/attributes merge upstream/22.0
# resolve remaining conflicts
git commit
git push origin

When creating the merge request do not squash the commits.

Warning If you were to put the core.attributeFiles setting into your .gitconfig file, the merge driver would be used for all your git commands and could have undesired side effects.

As a release coordinator you can apply updates to the attributes file directly in the master branch. If updates require wider discussion considering making a proper merge request and tag the relevant people.

Useful commands for resolving conflicts:

  • git merge --abort to abort the merge
  • git reset --hard upstream/master to start over with current branch
  • git [-n] revert HASH to revert a specific commit [without creating commit]
  • git checkout --ours FILE to keep version from master (or --theirs for 22.0) followed by git add FILE to mark conflict as resolved

On-demand release build

For emergencies the following procedure can be used to launch an on-demand release build. This would mainly be used in case a patch is required to an older version of the nightly branch. The procedure is very similar to building/deploying a regular nightly build, except that the release is being built from a fixed git tag.

  1. Prepare the git branch with the required patches
    • Create a new git branch with the name of the branching point, e.g. if a patch is required for release 22.0.60: 
      git fetch upstream --tags
git checkout -b 22.0.60-patches release/22.0.60

      In case there is already a patch release for this branch point, simply re-use the existing branch.

    • Apply the required patches to the branch and commit. In most cases you probably want to “cherry-pick” an existing merge request.
    • Update the release number in version.txt (e.g. 22.0.60.1). In case you have been re-using a branch in step 1, check the list of already existing tags via git tag -l 'release/22.0.60.*'.
    • Push the branch to the athena repository (not your fork): 
      git push upstream 22.0.60-patches
    • Tag the release in git (e.g. release/22.0.60.1). Make sure to explain in the “Release notes” which changes went into this tag.
    • After the tag has been created you can compare it to the original release.
  2. Use the Ondemand Jenkins job (tunnelling is necessary from outside CERN at present).
    • Log in with username “jobrest”. If you do not know the password, ask Alex Undrus.
    • Click “Build with parameters” on the left hand sidebar. Fill in the details on the screen where:
      • Executor_Label: leave it unchanged
      • project can be: Athena, AthSimulation, AnalysisBase, etc.
      • platform: x86_64-centos7-gcc11-opt
      • git_tag: release/22.0.60.1
      • compiler: gcc11 (needs to match the platform)
      • cmake version: 3.21.3 (>= regular nightly)
      • cuda version: 11.4
      • Then click “Build” (depending on the project this can take up to 9 hours)
  3. Once finished check the ondemand build results on NICOS and note the datestamp of the build.
  4. Deploy the release to cvmfs with the usual procedure, but use:
    • nightly_name: ondemand
    • rel_nightly: the datestamp from the NICOS page of this build (e.g. 2022-03-25T1152). You can also find this datestamp in the console output of the Jenkins job from step 2.

Setting up a stable branch

To set up a production branch, first make the base release (as above) so there is a clear branching point, and so the release numbering makes sense. Next, make a branch from this release, naming it descriptively e.g. 22.0-mc20. Another acceptable option would be to name it after the base release e.g. 22.0.41.X.

You should then setup permissions for this this branch allowing only the branch managers to push and merge (look for Protected branches under Repository Settings) and have a look at other protected branches for examples).

Next, it is very important to update the release candidate version (recall that in order to make make a release from a nightly, the nightly needs to know the release it will become) e.g. if you branched from 22.0.41, you should immediately change the version.txt in all relevant projects (i.e. all, except AnalysisBase and AthAnalysis) to 22.0.41.1.

Finally, do not forget to update the README.md with details about the new branch (ideally in all branches, but certainly in the branch and master).

Tagging a point (patch) release

In productions branches we will need to make patch or point releases, e.g. 22.0.41.1

The procedure should be exactly the same as above, namely:

  • Copy the RPMs of the nightly to EOS
  • Create a Jira ticket for CVMFS installation
  • Tag the release in git
  • Update the release candidate number to the next point release i.e. 22.0.41.1 becomes 22.0.41.2

Clean build directory on CI nodes

The CI compiles code-changes in the MRs incrementally. Occasionally, the build nodes end up in a bad state and need full rebuilds to recover. Updates to the externals frequently create this problem. This can be achieved by scheduling the clean-build-dir jobs on atlas-sit-ci.cern.ch after logging in via SSO. The ongoing CI jobs will be allowed to complete before the cleanup. All newcoming CI jobs will be waiting in the queue until the clean-build-dir jobs are completed on all slave nodes.

Locate the job clean-build-dir and select Build with Parameters. The default parameters should be fine:

Please announce the clean-up of the CI nodes outside of the regular weekly cleanup on the MR shifters mattermost channel at the link.