Farhad Rahimi Klie

Posted on Nov 18

A Complete Guide to CI/CD Pipelines — From Zero to Deployment

#kubernetes #automation #octopusdeploy #cicd

Modern software development moves fast. Teams push code daily (sometimes hourly), users expect rapid updates, and businesses want features delivered without breaking anything.
This is where CI/CD pipelines come in.

CI/CD—short for Continuous Integration and Continuous Delivery/Deployment—is the backbone of modern DevOps engineering. If you want to build reliable software at scale, you need CI/CD.

In this article, we’ll walk through:

What CI/CD actually means
Why CI/CD matters
How a CI/CD pipeline works internally
The key stages of a real-world pipeline
Example with GitHub Actions
Best practices

Let’s dive in! 🎯

🧩 What Is CI/CD?

🔵 Continuous Integration (CI)

Continuous Integration is the practice of frequently merging developer changes into the main codebase while automatically verifying they work.

CI involves:

Automatic builds
Running tests
Static code analysis
Checking code quality

The goal?
Catch bugs early — before they reach production.

🟢 Continuous Delivery (CD)

Continuous Delivery ensures that every code change is automatically tested and packaged so it’s always ready for deployment.

Code is automatically built
Automated tests run
Artifacts (Docker images, binaries, etc.) are generated
Release versions are prepared

Deployment is manual, but safe and one click away.

🔴 Continuous Deployment (also CD)

Continuous Deployment takes it one step further:

Every change that passes the pipeline is deployed to production automatically.

This means no manual approval — the system deploys code by itself.

🏗️ Why CI/CD Matters

Without CI/CD, teams face:

❌ Late bug discovery
❌ Manual deployments
❌ Merge conflicts
❌ Slow feature delivery
❌ High risk of broken production releases

With CI/CD, you get:

✅ Faster development
✅ Higher code confidence
✅ Repeatable deployments
✅ Lower human error
✅ Happier developers + users

This is why CI/CD is a must in any modern engineering team.

🛠️ What Does a CI/CD Pipeline Look Like?

Here is a simple visual representation:

      Developer Pushes Code
                 |
                 v
        [ Source Control ]
                 |
                 v
       +-------------------+
       |   Build Stage     |
       +-------------------+
                 |
                 v
       +-------------------+
       |   Test Stage      |
       +-------------------+
                 |
                 v
       +-------------------+
       | Artifact Packaging|
       +-------------------+
                 |
                 v
       +-------------------+
       |  Deploy/Release   |
       +-------------------+
                 |
                 v
            Production 🚀

🔧 Stages of a CI/CD Pipeline (Explained)

1. Source Stage

Triggered when code is pushed to a repository (GitHub, GitLab, Bitbucket).
Detects branches, pull requests, or tags.

2. Build Stage

Converts source code into an executable package.

Examples:

npm install + npm run build
mvn package
go build
Docker image creation

If it doesn't build, the pipeline stops.

3. Test Stage

Runs automated tests:

Unit tests
Integration tests
API tests
Security tests (SAST)

If any test fails → no merge, no deployment.

4. Code Quality & Security

Optional but highly recommended:

Linting
Code coverage analysis
Dependency vulnerability scans

Tools: SonarQube, ESLint, Bandit, Trivy

5. Artifact Packaging

The pipeline produces deployable artifacts:

Docker images
JAR/WAR files
Python wheels
Versioned zip files

These artifacts are stored in a registry (Nexus, GitHub Packages, Docker Hub).

6. Deployment Stage

Depending on the strategy:

🔵 Continuous Delivery → requires approval
🔴 Continuous Deployment → fully automated

Deploys to:

Kubernetes
AWS EC2 / Lambda
DigitalOcean
Docker Swarm
On-prem servers

🧪 Real Example: CI/CD With GitHub Actions

Below is a complete working Node.js CI/CD workflow example.

Create a file:
.github/workflows/ci.yml

name: CI Pipeline

on:
  push:
    branches: [ "main" ]
  pull_request:
    branches: [ "main" ]

jobs:
  build-and-test:
    runs-on: ubuntu-latest

    steps:
      - name: Checkout Repository
        uses: actions/checkout@v3

      - name: Setup Node.js
        uses: actions/setup-node@v3
        with:
          node-version: '20'

      - name: Install Dependencies
        run: npm install

      - name: Run Tests
        run: npm test

      - name: Build Project
        run: npm run build

  deploy:
    needs: build-and-test
    runs-on: ubuntu-latest
    if: github.ref == 'refs/heads/main'

    steps:
      - name: Deploy to Server
        run: |
          echo "Deploying..."
          # add SSH deployment commands here

This pipeline:

Runs on every push or PR
Installs dependencies
Runs tests
Builds the project
Deploys automatically (only from main branch)

🧨 Deployment Strategies (How You Ship Safely)

🔵 Blue-Green Deployment

Two environments (Blue and Green).
Deploy to one → switch traffic.

🟢 Canary Deployment

Release to 1% of users → 5% → 20% → 100%.

🟣 Rolling Deployment

Gradually replace old servers with new ones.

🔴 Hotfix Deployment

Deploy only specific patches quickly.

⭐ CI/CD Best Practices

✔ Automate everything

From build to tests to deployment.

✔ Keep pipelines fast

Slow pipelines kill productivity.

✔ Use versioned artifacts

Never rebuild the same code twice.

✔ Shift security left

Run SAST, dependency scans early.

✔ Deploy in small batches

More frequent releases = fewer bugs.

✔ Monitor and rollback

Always support quick rollback paths.

🚀 Final Thoughts

CI/CD is not just a tool.
It’s a culture of automation, quality, and fast delivery.

Whether you're a solo developer or a big engineering team, adopting CI/CD will:

Speed up your workflow
Reduce production bugs
Increase developer happiness
Make deployments boring (in the best way!)

If you're building modern software, a CI/CD pipeline is non-negotiable.

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