Course Introduction

• Practical, hands-on labs to experiment and learn by doing.
• Clear migration patterns and real-world examples to convert Jenkins jobs into GitHub Actions workflows.
• Strategies for handling secrets, artifacts, plugins, and environment variables during migration.

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Why migrate from Jenkins to GitHub Actions

• Native integration with GitHub repositories, pull requests, and the Actions Marketplace.
• Workflows defined in YAML stored in the repository for visibility and versioning.
• Reduced operational overhead — no need to manage Jenkins masters or plugin compatibility.
• Flexible runners: use GitHub-hosted runners or self-hosted runners for custom workloads.

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Course structure (what we’ll cover)

1. Jenkins fundamentals and what to migrate
2. GitHub Actions basics and YAML workflow patterns
3. Mapping Jenkins pipeline constructs to Actions jobs/steps
4. Handling secrets, artifacts, and environment variables
5. Tools and automation to accelerate migration
6. Labs: migrate a simple pipeline, then a complex pipeline with plugins and conditional logic

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Deep dive: Jenkins — what to look for

• Pipeline type: Declarative or Scripted (Groovy).
• Steps that call shell commands, invoke Docker, or use specific plugins.
• How secrets and credentials are stored (Jenkins credentials store).
• Artifact storage locations (Nexus, Artifactory, S3).
• Custom plugins that may not have direct GitHub Action equivalents.

// Jenkins (Declarative Pipeline)
pipeline {
  agent any
  stages {
    stage('Build') {
      steps {
        sh 'make build'
      }
    }
    stage('Test') {
      steps {
        sh 'make test'
      }
    }
  }
}

Results - <1s
> Job completed at Tue May 20 12:59:51 UTC 2025 — Print Message

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GitHub Actions fundamentals

name: CI

# Controls when the workflow will run
on:
  push:
    branches: ["main"]
  pull_request:
    branches: ["main"]

# Allows you to run this workflow manually from the Actions tab
workflow_dispatch:

jobs:
  build:
    # The type of runner that the job will run on
    runs-on: ubuntu-latest

    # Steps represent a sequence of tasks executed as part of the job
    steps:
      # Checks out your repository under $GITHUB_WORKSPACE, so your job can access it
      - name: Checkout repository
        uses: actions/checkout@v4

      # Example: set up Node.js, install dependencies, run tests
      - name: Set up Node.js
        uses: actions/setup-node@v4
        with:
          node-version: "18"

      - name: Install dependencies
        run: npm ci

      - name: Run tests
        run: npm test

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Mapping Jenkins concepts to GitHub Actions

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Example: Jenkins -> GitHub Actions direct conversion

# GitHub Actions equivalent
jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout repository
        uses: actions/checkout@v4

      - name: Build
        run: make build

      - name: Test
        run: make test

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Tools and automation to accelerate migration

• Use the GitHub Marketplace to find Actions that replace Jenkins plugins.
• Employ the gh CLI to create workflows, manage secrets, and interact with repos programmatically.
• For large fleets, write scripts to translate common patterns (e.g., shell steps) into YAML templates you can reuse.

# Homebrew (macOS / Linux)
brew install gh
brew upgrade gh

# MacPorts (macOS)
sudo port selfupdate
sudo port install gh

# Conda
conda install -c conda-forge gh
conda update -c conda-forge gh

• gh auth login — authenticate to GitHub.
• gh secret set — add repository secrets.
• gh repo clone / gh workflow — manage workflows and repos from scripts.

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Migration checklist

• Inventory all Jenkins jobs, pipelines, and plugins.
• Identify secrets and set them in GitHub Actions secrets.
• Map artifact stores and update publishing steps (e.g., to S3, Artifactory).
• Convert build and test steps to Actions jobs/steps.
• Replace or reimplement plugin functionality with Marketplace Actions or API calls.
• Create tests and smoke checks in GitHub Actions before decommissioning Jenkins.

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Links and references

• GitHub Actions documentation
• GitHub Marketplace
• GitHub CLI (gh)
• Jenkins documentation