How to do common things with Jenkins builds

See also Interacting with builds in Jenkins.

Add a new configuration to a build

To add a new configuration to an existing matrix build, the required steps vary a bit depending on how similar your configuration is to existing ones:

1. If the new configuration is just a new combination of existing options, it is sufficient to add the configuration to the respective file under admin/builds/, and test that it works. Changes to pre-submit-matrix.txt will automatically get verified when you upload your changes to Gerrit.
   1. If your combination requires a specific combination of software that is not yet available, you will need to update releng/agents.py in the releng repo, and possibly install that combination of software on a agent.
2. If the new configuration requires new options, but those options do not affect where the configuration can be built (i.e., do not require special software on the build agents), you need to update admin/builds/gromacs.py to specify the options and how they affect the build, and then add the configurations to the matrix in admin/builds/.
3. If the new configuration requires new options that affect job placement, you need to update
   • releng/options.py to specify the new option and a label for it,
   • releng/agents.py to specify which build agents support the option,
   • possibly releng/environment.py to specify special CMake options or other configuration (e.g., changes to PATH) that is required for the build to work with this option (if you need this, you also need to specify in releng/options.py that your new function in releng/environment.py should be called to process your new option),
   • possibly admin/builds/gromacs.py if your new option affects the build beyond the changes above, and
   • finally add the configuration to the matrix and test it.

Add a new build agent

To add a new agent to be used for builds, the steps are outlined below:

1. Install the agent so that Jenkins can connect to it and the agent can connect to Gerrit (this configuration is currently outside the scope of this documentation).
2. Install necessary software on the agent to be used in the builds (compilers and other tools). Please see releng/environment.py for how various programs are located, and install them on the new agent to be found in the same way (if something seems awkward, the approach should be changed on all agents, not by adding more variability).
3. Ensure that the agent is listed in releng/agents.py and has the correct labels and other constraints defined appropriately.
4. Ensure that the agent has relevant labels defined in Jenkins if it needs to run builds that rely on them (see Jenkins configuration).

If the agent does not get automatically used, follow steps above for adding a new configuration to use the agent if it is intended for building one or more matrix configurations.

Add builds for a new release branch

After creating a release branch (in both gromacs and regressiontests repositories; releng is only using a single branch (master)), the following steps are needed to have full Jenkins builds running for it:

• Clone all per-branch jobs in Jenkins from those for master. Currently this includes pre-submit, post-submit, and nightly matrix jobs, triggering pipelines for them, a nightly documentation build, and a release pipeline including two packaging builds. Work is in progress to remove the need for per-branch pre-submit and post-submit triggering pipelines.

  Adjust the Gerrit Trigger and/or SCM configuration and/or job parameter defaults for the cloned jobs to trigger from the correct branch. Also adjust the job descriptions if they contain branch-specific information.

  Adjust the pipeline jobs to reference the correct per-branch jobs (the matrix jobs are referenced from the triggering pipelines, and the packaging jobs from the release pipeline).

  Note that Copy Project link in Jenkins is not visible for pipeline jobs; you can achieve the same effect by selecting New Item at the top level and copying from an existing item.

  TODO: The number of jobs required here could be reduced.

• Adjust the Gerrit Trigger configuration for jobs that are not branch-specific and add the new branches as appropriate. Remove obsolete release branches from the triggering configuration. This step impacts non-matrix pre-submit verification jobs, and an on-demand pipeline job. Note that Releng_PreSubmit is only triggered from releng and does not need to be considered here.

  TODO: Consider either reducing the number of jobs affected, or consider using dynamic triggering configuration to be able to specify the supported branches in a single location.

• Adjust the list of branches for which workflow/releng-presubmit.groovy verifies the matrix configurations by editing the pipeline script.