Comprehensive Guide to Getting Started with Jenkins

Introduction

• Overview of the guide to Jenkins
• Includes theory and practical labs
• Jenkins is a valuable DevOps skill with high earning potential ($150,000 - $250,000/year)
• Capable of automating various tasks, including running scripts and playbooks
• Video contents:
  • Setting up Jenkins server
  • Managing Jenkins agents
  • Creating a declarative Jenkins pipeline with Groovy

What is Jenkins?

• Jenkins is an automation platform for building, testing, and deploying software using pipelines.
• Can automate any task, not just code pipelines.
• Provides a web GUI for creating jobs and customizing functionalities.
• Features include source control management, build triggers, and build management.

Jenkins Infrastructure

• Master Server: Controls pipelines and schedules builds to agents.
• Agents: Run builds in their workspace.
• Workflow Example:
  1. Developer commits code to a git repository.
  2. Jenkins master triggers the pipeline and distributes the build to an agent.
  3. Agent runs build commands (Linux commands).

Types of Jenkins Agents

1. Permanent Node Agents: Standalone Linux/Windows servers configured to run Jenkins jobs (Java and SSH required).
2. Cloud Agents: More commonly used in environments; examples include Docker, Kubernetes, and AWS.
   • Can dynamically spin up agents based on templates.
   • Lab demonstration of setting up Docker as a cloud agent.

Build Jobs in Jenkins

1. Freestyle Build Projects

• Simplest way to start with Jenkins.
• Shell scripts triggered by events (e.g. code commits).
• Managed through UI and plugins.

2. Pipelines

• Defined using Jenkins files written in Groovy syntax.
• Divided into stages (e.g., clone, build, test, package, deploy).

Jenkins Installation

• Installation options:
  • Directly onto the OS or in a container (Docker recommended).
• Installation steps:
  1. Build the Docker image.
  2. Create a network for Jenkins.
  3. Launch the container.
• Example commands provided for various OS.

Getting Started with Jenkins UI

• Key UI Features:
  • Breadcrumbs for navigation
  • New Item for creating projects/pipelines
  • Build History for job history
  • Manage Jenkins for configurations and plugins

Key Management Areas in Jenkins

• Configure System: Global settings
• Manage Plugins: Critical for updating and maintaining plugins.
• Manage Nodes and Clouds: Setting up agents (permanent/cloud).
• Security Settings: Configuring global security, managing users, and credentials.

Creating Your First Project

• Steps to create a Freestyle Project:
  1. Name your project (avoid spaces).
  2. Configure Source Control Management (Git repository).
  3. Setup Build Triggers (webhooks or polling SCM).
  4. Define Build Steps (execute shell commands).
• Example of a "Hello World" build.

Using Environment Variables

• Utilize Jenkins environment variables (e.g. build ID, build URL) in builds.

Troubleshooting and File System

• Access Jenkins file system via Docker exec for troubleshooting.
• Important folders: workspace, plugins, logs, configuration files.

Advanced Topics

Setting Up Agents & Pipelines

• Setting up permanent and cloud agents through Manage Jenkins.
• Overview of configuring Docker agents for pipelines.

Creating a Pipeline

• Steps to create a pipeline using Jenkins file:
  1. Define pipeline script or use Jenkins file from SCM.
  2. Create stages (build, test, deliver).
  3. Implement build commands and test commands.

Blue Ocean Plugin

• Introduction to Blue Ocean for enhanced Jenkins interface.
• Supports multi-stage pipelines and better visualizations.

Conclusion

• Summary of key skills learned:
  • Installing Jenkins master and agents
  • Managing freestyle projects
  • Building pipelines using Groovy
• Encouragement to ask questions and subscribe for more content.