// Module included in the following assemblies:
// * builds/build-strategies.adoc

:_mod-docs-content-type: CONCEPT
[id="builds-strategy-pipeline-mapping-buildconfig-jenkins_{context}"]
= Mapping between BuildConfig environment variables and Jenkins job parameters

When a Jenkins job is created or updated based on changes to a Pipeline strategy build configuration, any environment variables in the build configuration are mapped to Jenkins job parameters definitions, where the default values for the Jenkins job parameters definitions are the current values of the associated environment variables.

After the Jenkins job's initial creation, you can still add additional parameters to the job from the Jenkins console. The parameter names differ from the names of the environment variables in the build configuration. The parameters are honored when builds are started for those Jenkins jobs.

How you start builds for the Jenkins job dictates how the parameters are set.

* If you start with `oc start-build`, the values of the environment variables in the build configuration are the parameters set for the corresponding job instance. Any changes you make to the parameters' default values from the Jenkins console are ignored. The build configuration values take precedence.

* If you start with `oc start-build -e`, the values for the environment variables specified in the `-e` option take precedence.
** If you specify an environment variable not listed in the build configuration, they will be added as a Jenkins job parameter definitions.
** Any changes you make from the Jenkins console to the parameters corresponding to the environment variables are ignored. The build configuration and what you specify with `oc start-build -e` takes precedence.

* If you start the Jenkins job with the Jenkins console, then you can control the setting of the parameters with the Jenkins console as part of starting a build for the job.

[NOTE]
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It is recommended that you specify in the build configuration all possible environment variables to be associated with job parameters. Doing so reduces disk I/O and improves performance during Jenkins processing.
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