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Continuous Integration with Jenkins

Use Jenkins to automate your continuous integration process

In IBM Garage Method, one of the Develop practices is continuous integration. The Developer Environment uses a Jenkins pipeline to automate continuous integration.

What is continuous integration

Continuous integration is a software development technique where software is built regularly by a team in an automated fashion. This quote helps explain it:

Continuous Integration is a software development practice where members of a team integrate their work frequently, usually each person integrates at least daily - leading to multiple integrations per day. Each integration is verified by an automated build (including test) to detect integration errors as quickly as possible. Many teams find that this approach leads to significantly reduced integration problems and allows a team to develop cohesive software more rapidly

– Martin Fowler

What is Jenkins

Jenkins is a self-contained, open source automation server that can be used to automate all sorts of tasks related to building, testing, and delivering or deploying software. It is a perfect tool for helping manage continuous integration tasks for a wide range of software components.

Jenkins Pipeline (or simply “Pipeline”) is a suite of plugins that supports implementing and integrating continuous delivery pipelines into Jenkins.

A continuous delivery pipeline is an automated expression of your process for getting software from version control right through to your users and customers.

Jenkins Pipeline provides an extensible set of tools for modeling simple-to-complex delivery pipelines “as code.” The definition of a Jenkins Pipeline is typically written into a text file (called a Jenkinsfile) that in turn is checked into a project’s source control repository.

Pipelines

Pipelines offer a set of stages or steps that can be chained together to allow a level of software automation. This automation can be tailored to the specific project requirements.

You can read more information about Jenkins Pipelines here

Stages

Pipelines are defined in a Jenkinsfile that sits in the root of your application code. It defines a number of stages. Each of the Code Patterns includes a Jenkinsfile that offers a number of stages. The stages have been configured to complete the build, test, package, and deploy of the application code. Each stage can use the defined defined secrets and config maps that were previously configured during the installation of Development cluster setup.

Developer Tools Pipeline

To enable application compatibility between Kubernetes and OpenShift, the Jenkinsfile is consistent between pipeline registration with both platforms. Also, the Docker images are built from UBI images so that their containers can run on both platforms.

These are the stages in the pipeline and a description of what each stage does. The bold stage names indicate the stages that are required; the italics stage names indicate optional stages that can be deleted or will be ignored if the tool supporting the stage is not installed. These stages represent a typical production pipeline flow for a cloud-native application.

  • Setup: Clones the code into the pipeline
  • Build: Runs the build commands for the code
  • Test: Validates the unit tests for the code
  • Publish pacts: Publishes any pact contracts that have been defined
  • Sonar scan: Runs a sonar code scan of the source code and publishes the results to SonarQube
  • Verify environment: Validates the OpenShift or IKS environment configuration is valid
  • Build image: Builds the code into a Docker images and stores it in the IBM Cloud Image registry
  • Deploy to DEV env: Deploys the Docker image tagged version to dev namespace using Helm Chart
  • Health Check: Validates the Health Endpoint of the deployed application
  • Package Helm Chart: Stores the tagged version of the Helm chart in Artifactory
  • Trigger CD Pipeline: This is a GitOps stage that will update the build number in designated git repo and trigger ArgoCD for deployment to test

Registering Pipelines

The Code Patterns are a good place to start to see how Jenkinsfile and Dockerfile should be configured for use in a Jenkins CI pipeline. To register your git repo, use the IGC CLI. This command automates a number of manual steps you would have to do with Jenkins, including: managing secrets, webhooks, and pipeline registration in the Jenkins tools.

igc pipeline

By default, the pipeline will register into the dev namespace and will copy all the configMaps and secrets from the tools namespace to the dev namespace. This means the pipeline can execute, knowing it has access to the key information that enables it to integrate with both the cloud platform and the various development tools. See Cluster Configuration for more detailed information.

Registering Pipeline in new namespace

You can use any namespace you want to register a pipeline. If you add -n or namespace to your igc pipeline command, it will create a new namespace if it doesn’t already exist. It will copy the necessary secrets and configMaps into that namespace and configure the build agents pods to run in that namespace.

igc pipeline -n team-one

This is good if you have various squads, teams, pairs or students working in the same Development Tools environment.

Continuous deployment

In addition to continuous integration, the Developer Environment also supports continuous delivery using Artifactory and ArgoCD: