Chapter 3. Migrating from Jenkins to Tekton 3.1. Migrating from Jenkins to Tekton Jenkins and Tekton are extensively used to automate the process of building, testing, and deploying applications and projects. However, Tekton is a cloud-native CI/CD solution that works seamlessly with Kubernetes and OpenShift Container Platform. This document helps you migrate your Jenkins CI/CD workflows to Tekton. 3.1.1. Comparison of Jenkins and Tekton concepts This section summarizes the basic terms used in Jenkins and Tekton, and compares the equivalent terms. 3.1.1.1. Jenkins terminology Jenkins offers declarative and scripted pipelines that are extensible using shared libraries and plugins. Some basic terms in Jenkins are as follows: Pipeline : Automates the entire process of building, testing, and deploying applications, using the Groovy syntax. Node : A machine capable of either orchestrating or executing a scripted pipeline. Stage : A conceptually distinct subset of tasks performed in a pipeline. Plugins or user interfaces often use this block to display status or progress of tasks. Step : A single task that specifies the exact action to be taken, either by using a command or a script. 3.1.1.2. Tekton terminology Tekton uses the YAML syntax for declarative pipelines and consists of tasks. Some basic terms in Tekton are as follows: Pipeline : A set of tasks in a series, in parallel, or both. Task : A sequence of steps as commands, binaries, or scripts. PipelineRun : Execution of a pipeline with one or more tasks. TaskRun : Execution of a task with one or more steps. Note You can initiate a PipelineRun or a TaskRun with a set of inputs such as parameters and workspaces, and the execution results in a set of outputs and artifacts. Workspace : In Tekton, workspaces are conceptual blocks that serve the following purposes: Storage of inputs, outputs, and build artifacts. Common space to share data among tasks. Mount points for credentials held in secrets, configurations held in config maps, and common tools shared by an organization. Note In Jenkins, there is no direct equivalent of Tekton workspaces. You can think of the control node as a workspace, as it stores the cloned code repository, build history, and artifacts. In situations where a job is assigned to a different node, the cloned code and the generated artifacts are stored in that node, but the build history is maintained by the control node. 3.1.1.3. Mapping of concepts The building blocks of Jenkins and Tekton are not equivalent, and a comparison does not provide a technically accurate mapping. The following terms and concepts in Jenkins and Tekton correlate in general: Table 3.1. Jenkins and Tekton - basic comparison Jenkins Tekton Pipeline Pipeline and PipelineRun Stage Task Step A step in a task 3.1.2. Migrating a sample pipeline from Jenkins to Tekton This section provides equivalent examples of pipelines in Jenkins and Tekton and helps you to migrate your build, test, and deploy pipelines from Jenkins to Tekton. 3.1.2.1. Jenkins pipeline Consider a Jenkins pipeline written in Groovy for building, testing, and deploying: pipeline { agent any stages { stage('Build') { steps { sh 'make' } } stage('Test'){ steps { sh 'make check' junit 'reports/**/*.xml' } } stage('Deploy') { steps { sh 'make publish' } } } } 3.1.2.2. Tekton pipeline In Tekton, the equivalent example of the Jenkins pipeline comprises of three tasks, each of which can be written declaratively using the YAML syntax: Example build task apiVersion: tekton.dev/v1beta1 kind: Task metadata: name: myproject-build spec: workspaces: - name: source steps: - image: my-ci-image command: ["make"] workingDir: USD(workspaces.source.path) Example test task: apiVersion: tekton.dev/v1beta1 kind: Task metadata: name: myproject-test spec: workspaces: - name: source steps: - image: my-ci-image command: ["make check"] workingDir: USD(workspaces.source.path) - image: junit-report-image script: | #!/usr/bin/env bash junit-report reports/**/*.xml workingDir: USD(workspaces.source.path) Example deploy task: apiVersion: tekton.dev/v1beta1 kind: Task metadata: name: myprojectd-deploy spec: workspaces: - name: source steps: - image: my-deploy-image command: ["make deploy"] workingDir: USD(workspaces.source.path) You can combine the three tasks sequentially to form a Tekton pipeline: Example: Tekton pipeline for building, testing, and deployment apiVersion: tekton.dev/v1beta1 kind: Pipeline metadata: name: myproject-pipeline spec: workspaces: - name: shared-dir tasks: - name: build taskRef: name: myproject-build workspaces: - name: source workspace: shared-dir - name: test taskRef: name: myproject-test workspaces: - name: source workspace: shared-dir - name: deploy taskRef: name: myproject-deploy workspaces: - name: source workspace: shared-dir 3.1.3. Migrating from Jenkins plugins to Tekton Hub tasks You can extend the capability of Jenkins by using plugins . To achieve similar extensibility in Tekton, use any of the available tasks from Tekton Hub . As an example, consider the git-clone task available in the Tekton Hub, that corresponds to the git plugin for Jenkins. Example: git-clone task from Tekton Hub apiVersion: tekton.dev/v1beta1 kind: Pipeline metadata: name: demo-pipeline spec: params: - name: repo_url - name: revision workspaces: - name: source tasks: - name: fetch-from-git taskRef: name: git-clone params: - name: url value: USD(params.repo_url) - name: revision value: USD(params.revision) workspaces: - name: output workspace: source 3.1.4. Extending Tekton capabilities using custom tasks and scripts In Tekton, if you do not find the right task in Tekton Hub, or need greater control over tasks, you can create custom tasks and scripts to extend Tekton's capabilities. Example: Custom task for running the maven test command apiVersion: tekton.dev/v1beta1 kind: Task metadata: name: maven-test spec: workspaces: - name: source steps: - image: my-maven-image command: ["mvn test"] workingDir: USD(workspaces.source.path) Example: Execute a custom shell script by providing its path ... steps: image: ubuntu script: | #!/usr/bin/env bash /workspace/my-script.sh ... Example: Execute a custom Python script by writing it in the YAML file ... steps: image: python script: | #!/usr/bin/env python3 print("hello from python!") ... 3.1.5. Comparison of Jenkins and Tekton execution models Jenkins and Tekton offer similar functions but are different in architecture and execution. This section outlines a brief comparison of the two execution models. Table 3.2. Comparison of execution models in Jenkins and Tekton Jenkins Tekton Jenkins has a control node. Jenkins executes pipelines and steps centrally, or orchestrates jobs running in other nodes. Tekton is serverless and distributed, and there is no central dependency for execution. The containers are launched by the control node through the pipeline. Tekton adopts a 'container-first' approach, where every step is executed as a container running in a pod (equivalent to nodes in Jenkins). Extensibility is achieved using plugins. Extensibility is achieved using tasks in Tekton Hub, or by creating custom tasks and scripts. 3.1.6. Examples of common use cases Both Jenkins and Tekton offer capabilities for common CI/CD use cases, such as: Compiling, building, and deploying images using maven Extending the core capabilities by using plugins Reusing shareable libraries and custom scripts 3.1.6.1. Running a maven pipeline in Jenkins and Tekton You can use maven in both Jenkins and Tekton workflows for compiling, building, and deploying images. To map your existing Jenkins workflow to Tekton, consider the following examples: Example: Compile and build an image and deploy it to OpenShift using maven in Jenkins #!/usr/bin/groovy node('maven') { stage 'Checkout' checkout scm stage 'Build' sh 'cd helloworld && mvn clean' sh 'cd helloworld && mvn compile' stage 'Run Unit Tests' sh 'cd helloworld && mvn test' stage 'Package' sh 'cd helloworld && mvn package' stage 'Archive artifact' sh 'mkdir -p artifacts/deployments && cp helloworld/target/*.war artifacts/deployments' archive 'helloworld/target/*.war' stage 'Create Image' sh 'oc login https://kubernetes.default -u admin -p admin --insecure-skip-tls-verify=true' sh 'oc new-project helloworldproject' sh 'oc project helloworldproject' sh 'oc process -f helloworld/jboss-eap70-binary-build.json | oc create -f -' sh 'oc start-build eap-helloworld-app --from-dir=artifacts/' stage 'Deploy' sh 'oc new-app helloworld/jboss-eap70-deploy.json' } Example: Compile and build an image and deploy it to OpenShift using maven in Tekton. apiVersion: tekton.dev/v1beta1 kind: Pipeline metadata: name: maven-pipeline spec: workspaces: - name: shared-workspace - name: maven-settings - name: kubeconfig-dir optional: true params: - name: repo-url - name: revision - name: context-path tasks: - name: fetch-repo taskRef: name: git-clone workspaces: - name: output workspace: shared-workspace params: - name: url value: "USD(params.repo-url)" - name: subdirectory value: "" - name: deleteExisting value: "true" - name: revision value: USD(params.revision) - name: mvn-build taskRef: name: maven runAfter: - fetch-repo workspaces: - name: source workspace: shared-workspace - name: maven-settings workspace: maven-settings params: - name: CONTEXT_DIR value: "USD(params.context-path)" - name: GOALS value: ["-DskipTests", "clean", "compile"] - name: mvn-tests taskRef: name: maven runAfter: - mvn-build workspaces: - name: source workspace: shared-workspace - name: maven-settings workspace: maven-settings params: - name: CONTEXT_DIR value: "USD(params.context-path)" - name: GOALS value: ["test"] - name: mvn-package taskRef: name: maven runAfter: - mvn-tests workspaces: - name: source workspace: shared-workspace - name: maven-settings workspace: maven-settings params: - name: CONTEXT_DIR value: "USD(params.context-path)" - name: GOALS value: ["package"] - name: create-image-and-deploy taskRef: name: openshift-client runAfter: - mvn-package workspaces: - name: manifest-dir workspace: shared-workspace - name: kubeconfig-dir workspace: kubeconfig-dir params: - name: SCRIPT value: | cd "USD(params.context-path)" mkdir -p ./artifacts/deployments && cp ./target/*.war ./artifacts/deployments oc new-project helloworldproject oc project helloworldproject oc process -f jboss-eap70-binary-build.json | oc create -f - oc start-build eap-helloworld-app --from-dir=artifacts/ oc new-app jboss-eap70-deploy.json 3.1.6.2. Extending the core capabilities of Jenkins and Tekton by using plugins Jenkins has the advantage of a large ecosystem of numerous plugins developed over the years by its extensive user base. You can search and browse the plugins in the Jenkins Plugin Index . Tekton also has many tasks developed and contributed by the community and enterprise users. A publicly available catalog of reusable Tekton tasks are available in the Tekton Hub . In addition, Tekton incorporates many of the plugins of the Jenkins ecosystem within its core capabilities. For example, authorization is a critical function in both Jenkins and Tekton. While Jenkins ensures authorization using the Role-based Authorization Strategy plugin, Tekton uses OpenShift's built-in Role-based Access Control system. 3.1.6.3. Sharing reusable code in Jenkins and Tekton Jenkins shared libraries provide reusable code for parts of Jenkins pipelines. The libraries are shared between Jenkinsfiles to create highly modular pipelines without code repetition. Although there is no direct equivalent of Jenkins shared libraries in Tekton, you can achieve similar workflows by using tasks from the Tekton Hub , in combination with custom tasks and scripts. 3.1.7. Additional resources Role-based Access Control

Commands:
pipeline { agent any stages { stage('Build') { steps { sh 'make' } } stage('Test'){ steps { sh 'make check' junit 'reports/**/*.xml' } } stage('Deploy') { steps { sh 'make publish' } } } }
apiVersion: tekton.dev/v1beta1 kind: Task metadata: name: myproject-build spec: workspaces: - name: source steps: - image: my-ci-image command: ["make"] workingDir: USD(workspaces.source.path)
apiVersion: tekton.dev/v1beta1 kind: Task metadata: name: myproject-test spec: workspaces: - name: source steps: - image: my-ci-image command: ["make check"] workingDir: USD(workspaces.source.path) - image: junit-report-image script: | #!/usr/bin/env bash junit-report reports/**/*.xml workingDir: USD(workspaces.source.path)
apiVersion: tekton.dev/v1beta1 kind: Task metadata: name: myprojectd-deploy spec: workspaces: - name: source steps: - image: my-deploy-image command: ["make deploy"] workingDir: USD(workspaces.source.path)
apiVersion: tekton.dev/v1beta1 kind: Pipeline metadata: name: myproject-pipeline spec: workspaces: - name: shared-dir tasks: - name: build taskRef: name: myproject-build workspaces: - name: source workspace: shared-dir - name: test taskRef: name: myproject-test workspaces: - name: source workspace: shared-dir - name: deploy taskRef: name: myproject-deploy workspaces: - name: source workspace: shared-dir
apiVersion: tekton.dev/v1beta1 kind: Pipeline metadata: name: demo-pipeline spec: params: - name: repo_url - name: revision workspaces: - name: source tasks: - name: fetch-from-git taskRef: name: git-clone params: - name: url value: USD(params.repo_url) - name: revision value: USD(params.revision) workspaces: - name: output workspace: source
apiVersion: tekton.dev/v1beta1 kind: Task metadata: name: maven-test spec: workspaces: - name: source steps: - image: my-maven-image command: ["mvn test"] workingDir: USD(workspaces.source.path)
steps: image: ubuntu script: | #!/usr/bin/env bash /workspace/my-script.sh
steps: image: python script: | #!/usr/bin/env python3 print("hello from python!")
#!/usr/bin/groovy node('maven') { stage 'Checkout' checkout scm stage 'Build' sh 'cd helloworld && mvn clean' sh 'cd helloworld && mvn compile' stage 'Run Unit Tests' sh 'cd helloworld && mvn test' stage 'Package' sh 'cd helloworld && mvn package' stage 'Archive artifact' sh 'mkdir -p artifacts/deployments && cp helloworld/target/*.war artifacts/deployments' archive 'helloworld/target/*.war' stage 'Create Image' sh 'oc login https://kubernetes.default -u admin -p admin --insecure-skip-tls-verify=true' sh 'oc new-project helloworldproject' sh 'oc project helloworldproject' sh 'oc process -f helloworld/jboss-eap70-binary-build.json | oc create -f -' sh 'oc start-build eap-helloworld-app --from-dir=artifacts/' stage 'Deploy' sh 'oc new-app helloworld/jboss-eap70-deploy.json' }
apiVersion: tekton.dev/v1beta1 kind: Pipeline metadata: name: maven-pipeline spec: workspaces: - name: shared-workspace - name: maven-settings - name: kubeconfig-dir optional: true params: - name: repo-url - name: revision - name: context-path tasks: - name: fetch-repo taskRef: name: git-clone workspaces: - name: output workspace: shared-workspace params: - name: url value: "USD(params.repo-url)" - name: subdirectory value: "" - name: deleteExisting value: "true" - name: revision value: USD(params.revision) - name: mvn-build taskRef: name: maven runAfter: - fetch-repo workspaces: - name: source workspace: shared-workspace - name: maven-settings workspace: maven-settings params: - name: CONTEXT_DIR value: "USD(params.context-path)" - name: GOALS value: ["-DskipTests", "clean", "compile"] - name: mvn-tests taskRef: name: maven runAfter: - mvn-build workspaces: - name: source workspace: shared-workspace - name: maven-settings workspace: maven-settings params: - name: CONTEXT_DIR value: "USD(params.context-path)" - name: GOALS value: ["test"] - name: mvn-package taskRef: name: maven runAfter: - mvn-tests workspaces: - name: source workspace: shared-workspace - name: maven-settings workspace: maven-settings params: - name: CONTEXT_DIR value: "USD(params.context-path)" - name: GOALS value: ["package"] - name: create-image-and-deploy taskRef: name: openshift-client runAfter: - mvn-package workspaces: - name: manifest-dir workspace: shared-workspace - name: kubeconfig-dir workspace: kubeconfig-dir params: - name: SCRIPT value: | cd "USD(params.context-path)" mkdir -p ./artifacts/deployments && cp ./target/*.war ./artifacts/deployments oc new-project helloworldproject oc project helloworldproject oc process -f jboss-eap70-binary-build.json | oc create -f - oc start-build eap-helloworld-app --from-dir=artifacts/ oc new-app jboss-eap70-deploy.json