Chapter 3. Customizing GitLab pipelines and rebuilding container images
When customizing pipelines in GitLab, rebuilding container image is a critical step to ensure your changes are included in the updated workflow.
Pipelines in GitLab rely on specific container image, such as the GitLab runner image, to execute the tasks defined in your CI/CD workflow. The GitLab runner image provides the necessary tools, configuration, and scripts required for your pipeline to run. If you modify tasks in the pipeline, you must update and rebuild the container image to include those changes. This ensures that you pipeline tasks are properly executed when the pipeline is triggered.
Rebuilding container image involves the following steps:
-
Running
podmanto extract the existing pipeline files. - Customizing the pipeline tasks as per your requirements.
- Rebuilding the container image.
- Pushing the updated image to a container registry.
Prerequisites
Before making changes, ensure that:
-
You have
podmaninstalled on your system. - You have login credentials for Quay.io to push the updated image.
- You have forked and cloned the Sample templates repository.
- Your forked repository is up to date and synced with the upstream repository.
Procedure
Create a directory for the build resources. The location of the directory depends on your role:
-
Platform engineer: If you are rebuilding the image to update the default pipeline for your organization, you may create the directory within the location where you forked the
tssc-sample-templatesrepository. For example,rebuild-image. -
Developers: If you are rebuilding the image for your own use or a specific project, create a directory in a location outside the organization-wide fork of
tssc-sample-templatesto avoid conflicts.
mkdir rebuild-image-
Platform engineer: If you are rebuilding the image to update the default pipeline for your organization, you may create the directory within the location where you forked the
Run the following command and copy the container
imageURL:more ../tssc-sample-templates/skeleton/ci/source-repo/gitlabci/.gitlab-ci.yml # Example: ... image: registry.access.redhat.com/rhtap-task-runner/rhtap-task-runner-rhel9:1.5 ...Copy the existing pipeline content locally by running the following command:
podman run -v $(pwd):/pwd:z <The_url_you_copied_in_step_2> cp -r /work/rhtap /pwd1 - 1
- This command starts the container using the
<the_url_you_copied_in_step_2>image. It then copies the pipeline files from /work/rhtap inside the container to your working directory ($(pwd)). Additionally, if you are not on a system with SELinux enabled (for example, Fedora, RHEL, pr CentOS), remove the:zoption in the command to ensure compatibility.
-
Navigate to the
rhtapdirectory and customize the pipelines tasks as required. Create a
Dockerfilein therebuild-imagedirectory and add the following content to include your changes in the container. Additionally, the base imageregistry.access.redhat.com/rhtap-task-runner/rhtap-task-runner-rhel9:1.5is built onubi/ubi-minimal, which provides a lightweight Universal Base Image (UBI). If you need to install additional software and dependencies, usemicrodnf. An example command:FROM registry.access.redhat.com/rhtap-task-runner/rhtap-task-runner-rhel9:1.51 #Copy the updated pipeline tasks COPY ./rhtap /work/rhtap2 # Example: Install additional software (for example, git) RUN microdnf -y install make3 Build the new container image with the following command:
podman build -f Dockerfile -t quay.io/<namespace>/<new_image_name>1 - 1
-f Dockerfilespecifies the Dockerfile to use for the build the container image. The-fflag allows you to explicitly point to the Dockerfile if it’s not namedDockerfileor is located in a different directory.-t quay.io/<namespace>/<new_image_name>assigns a tag (name) to the container image for easy identification.
Login to Quay.io and push the updated image:
podman login quay.io # Enter username and password podman push quay.io/<namespace>/<new_image_name>1 - 1
- This uploads the customized container image to Quay.io, making it available for use in GitLab pipelines.
Platform engineer only: Navigate to tssc-sample-templates > skeleton > ci > source-repo > gitlabci >
.gitlab-ci.ymlfile and replace the container image URL with the one you just created. This makes the new container image as the default.image: quay.io/<namespace>/<new_image_name>For developers only: To update the container image just for a single repository in GitLab:
-
Navigate to the source repository >
.gitlab-ci.yamland replace the container image URL with the one you just created.
image: quay.io/<namespace>/<new_image_name>-
Navigate to the source repository >
- Commit and push the changes to apply the updated pipeline configuration.