Jenkins Cheat Sheet

A Jenkins cheat sheet covering essential concepts, commands, and configurations to help you get started and streamline your CI/CD processes.

Jenkins Cheat Sheet

1. Basic Concepts

• Jenkins: An open-source automation server used to build, test, and deploy software.

• Job: A single unit of work in Jenkins, such as building a project.

• Pipeline: A sequence of steps that define the process of building, testing, and deploying code.

• Node: A machine that Jenkins uses to execute jobs. The main server is known as the master node.

• Agent: A machine that is configured to execute jobs for the Jenkins master.

2. Common Jenkins Commands

• Start Jenkins:

    bashCopy codesudo systemctl start jenkins  # For systemd-based systems
    sudo service jenkins start    # For older init.d systems
  

• Stop Jenkins:

    bashCopy codesudo systemctl stop jenkins   # For systemd-based systems
    sudo service jenkins stop     # For older init.d systems
  

• Restart Jenkins:

    bashCopy codesudo systemctl restart jenkins  # For systemd-based systems
    sudo service jenkins restart    # For older init.d systems
  

• Check Jenkins Status:

    bashCopy codesudo systemctl status jenkins   # For systemd-based systems
    sudo service jenkins status     # For older init.d systems
  

  3. Jenkins Configuration

  • Access Jenkins: Open your web browser and navigate to http://<your-server-ip>:8080.

  • Manage Jenkins:

    • Go to Manage Jenkins for global configurations, plugin management, and system settings.

  • Manage Plugins:

    • Install Plugin: Go to Manage Jenkins > Manage Plugins > Available, search for the plugin, and click Install without restart.

    • Update Plugin: Go to Manage Jenkins > Manage Plugins > Updates.

4. Job Configuration

• Create a New Job:

  • Go to the Jenkins dashboard, click New Item, enter a name, select a job type (e.g., Freestyle project, Pipeline), and click OK.

• Configure SCM (Source Code Management):

  • Git:

    • URL: https://github.com/username/repository.git

    • Credentials: Add GitHub credentials.

  • GitHub: Use the GitHub plugin for easier integration.

• Build Triggers:

  • Poll SCM: Set up a cron-like schedule to poll the SCM for changes.

  • GitHub Hook Trigger: Set up a webhook on GitHub to trigger builds on code changes.

• Build Steps:

  • Execute Shell: Run shell commands.

  • Invoke Ant/Gradle/Maven: Build using specific tools.

  • Execute Windows Batch Command: Run commands in a Windows environment.

• Post-Build Actions:

  • Archive Artifacts: Specify files to archive after a build (e.g., *.jar).

  • Send Email: Configure email notifications for build results.

5. Pipeline Configuration

• Declarative Pipeline:

    groovyCopy codepipeline {
        agent any
        stages {
            stage('Build') {
                steps {
                    echo 'Building...'
                }
            }
            stage('Test') {
                steps {
                    echo 'Testing...'
                }
            }
            stage('Deploy') {
                steps {
                    echo 'Deploying...'
                }
            }
        }
        post {
            success {
                echo 'Pipeline succeeded!'
            }
            failure {
                echo 'Pipeline failed.'
            }
        }
    }
  

• Scripted Pipeline:

    groovyCopy codenode {
        stage('Build') {
            echo 'Building...'
        }
        stage('Test') {
            echo 'Testing...'
        }
        stage('Deploy') {
            echo 'Deploying...'
        }
        catchError {
            echo 'Handling errors...'
        }
    }
  

6. Jenkins User Management

• Add User:

  • Go to Manage Jenkins > Manage Users and click Create User.

• Assign Roles:

  • Use Role-based Authorization Strategy plugin to manage roles and permissions.

7. Jenkins Security

• Change Admin Password:

  • Go to Manage Jenkins > Configure Global Security and update credentials.

• Enable HTTPS:

  • Configure Jenkins to use HTTPS by setting up a reverse proxy with Apache/Nginx or using Jenkins' built-in SSL support.

8. Backup and Restore

• Backup Jenkins:

  • Manual Backup: Copy the Jenkins home directory (/var/lib/jenkins).

  • Automated Backup: Use plugins like ThinBackup for automated backups.

• Restore Jenkins:

  • Manual Restore: Copy the backup files to the Jenkins home directory and restart Jenkins.

9. Common Issues and Fixes

• Jenkins Not Starting:

  • Check logs: /var/log/jenkins/jenkins.log.

  • Ensure there’s enough disk space and permissions are correct.

• Job Fails to Build:

  • Check console output for error messages.

  • Verify SCM configurations and credentials.

10. Useful Jenkins Plugins

• GitHub Integration Plugin: Connects Jenkins with GitHub.

• Pipeline Plugin: Enables complex workflows using pipelines.

• Blue Ocean: Provides a modern UI for Jenkins pipelines.

• Slack Notification Plugin: Sends build notifications to Slack.