CI/CD Pipeline

What Is a CI/CD Pipeline?

A CI/CD pipeline is an automated sequence of steps that takes code changes from development to production. It encompasses compiling, testing, packaging, and deploying software – all automated and reproducible. For mid-market companies, this means fewer manual errors, faster releases, and more reliable software.

Without CI/CD, deployment often happens manually – a developer copies files via FTP to the server or runs a series of commands manually. This is error-prone, time-consuming, and poorly documented. A CI/CD pipeline eliminates these risks.

Continuous Integration (CI)

Continuous Integration means developers integrate their code changes into a central repository multiple times a day. Each integration automatically triggers a build and test suite. Errors are detected immediately rather than weeks later during manual merging.

The typical steps of a CI phase are:

• Code Checkout: The current code is fetched from the repository.
• Build: The application is compiled or built (e.g., creating a Docker image).
• Unit Tests: Automated tests verify individual functions.
• Code Quality: Static code analysis (linting, security scans) is performed.
• Artefact Creation: The finished build artefact is stored (e.g., in a container registry).

Continuous Delivery vs. Continuous Deployment

Continuous Delivery and Continuous Deployment are often confused but differ in one important aspect:

• Continuous Delivery: Every code change is automatically brought to production-readiness, but the final production deployment requires manual approval. Ideal for regulated environments or companies building confidence gradually.
• Continuous Deployment: Every successful code change is automatically deployed to production – without manual approval. Requires excellent test coverage and monitoring.

CI/CD Tools Compared

GitHub Actions

GitHub Actions is directly integrated into GitHub and offers YAML-based pipeline definitions. For teams already using GitHub, it is the simplest entry point. The free tier offers 2,000 minutes per month for private repositories.

GitLab CI/CD

GitLab CI/CD is part of the GitLab platform and provides a comprehensive all-in-one DevOps solution. The pipeline is defined in a .gitlab-ci.yml file. GitLab CI is particularly strong for self-hosted installations.

Jenkins

Jenkins is the oldest and most flexible CI/CD tool with over 1,800 plugins. However, setup and maintenance are complex. For new projects, we recommend more modern alternatives, but existing Jenkins installations can be migrated gradually.

AWS CodePipeline

CodePipeline is AWS's native CI/CD service. It integrates seamlessly with other AWS services like CodeBuild, CodeDeploy, and ECR. Suitable for teams working entirely within the AWS ecosystem.

Building a CI/CD Pipeline – Practical Example

A typical scenario for a mid-market company: a software team develops a web application and deploys to AWS EKS. The pipeline might look like this:

• Step 1: Developer pushes code to the main branch in GitHub.
• Step 2: GitHub Actions starts the build – Docker image is created.
• Step 3: Unit tests, integration tests, and security scans run automatically.
• Step 4: On success, the Docker image is pushed to the container registry (ECR).
• Step 5: The new image is automatically deployed to the staging cluster.
• Step 6: After manual approval (Continuous Delivery), it is deployed to production.

Tips for the Mittelstand

Start simple: a pipeline that only builds and tests is better than no pipeline. Automate deployment to staging first, then to production. Invest in good tests – they are the foundation for confidence in automated deployment. And document your pipeline so new team members become productive quickly.