CI/CD Explained: From Code Commit to Deployment

Modern software teams often release changes much faster than they did in the past. Instead of manually building, testing and deploying every application update, teams can automate many of these steps using CI/CD.

CI/CD is an important part of modern DevOps. It connects source code management, automated builds, testing and application deployment into a repeatable workflow.

Simple definition:
CI/CD is a collection of practices and automation that helps software teams integrate, test and deliver application changes more consistently.

In this guide, we will follow a typical CI/CD pipeline from a developer's code commit all the way to deployment.

What Does CI Mean?

CI stands for Continuous Integration.

Continuous Integration is the practice of frequently integrating code changes into a shared codebase and using automated processes to build and test those changes.

The goal is to discover problems earlier rather than waiting until many changes have accumulated.

Typical CI idea:

Developer changes code
↓
Commit changes
↓
Automated build
↓
Automated tests
↓
Feedback

What Does CD Mean?

The second part of CI/CD is CD.

CD can refer to Continuous Delivery or Continuous Deployment. Although the terms are closely related, there is an important distinction.

Continuous Delivery

Continuous Delivery means that application changes are automatically prepared and kept in a releasable state. A production release may still require an explicit approval or decision.

Continuous Deployment

Continuous Deployment goes one step further by automatically deploying changes that successfully pass the required pipeline checks.

Concept	Basic Idea
Continuous Integration	Frequently integrate, build and test code changes.
Continuous Delivery	Keep validated changes ready for release.
Continuous Deployment	Automatically deploy validated changes.

What Is a CI/CD Pipeline?

A CI/CD pipeline is an automated sequence of steps that takes application changes through processes such as building, testing and deployment.

A simple pipeline might look like this:

Basic CI/CD Pipeline

Code
Commit

→

Build
Package

→

Test
Validate

→

Release
Approve

→

Deploy
Run

Step 1: Developer Commits Code

A developer makes a change to the application and commits it to a Git repository.

For example:

git add .
git commit -m "Update login page"
git push

The remote repository can be configured to trigger the CI/CD pipeline when the change is pushed.

Step 2: The Pipeline Starts

A CI/CD system detects the repository change and starts the configured workflow.

Different organizations use different tools and platforms. The exact syntax and user interface therefore varies, but the underlying concepts are similar.

A pipeline may first check out the source code and prepare the environment required for the build.

Step 3: Build the Application

The pipeline can then build the application or create a deployable artifact.

For a containerized application, the pipeline might build a Docker image:

docker build -t my-app:1.0 .

The resulting image can become an artifact used by later stages of the deployment process.

Step 4: Run Automated Tests

Automated tests help determine whether the new code behaves as expected.

Depending on the application, a pipeline may run:

• Unit tests
• Integration tests
• API tests
• Security checks
• Code quality checks
• Container image checks

If an important test fails, the pipeline can stop before the application reaches the deployment stage.

Why automate testing?
Automated tests provide fast and repeatable feedback whenever code changes are introduced.

Step 5: Package the Application

After successful validation, the pipeline may create or publish an artifact.

Depending on the application, an artifact could be:

• A compiled application package
• A container image
• A deployment package
• A library package
• Another versioned build artifact

Versioning artifacts is important because deployment systems need to know exactly which application version they are deploying.

Container Images and Registries

Container-based applications commonly publish their images to a container registry.

Git Repository
↓
CI Pipeline
↓
Docker Build
↓
Container Image
↓
Container Registry
↓
Deployment Environment

A registry provides a location where deployment systems can retrieve the required image.

Step 6: Deploy the Application

Once the application has passed the required checks, it can be deployed to an environment such as development, staging or production.

In a Kubernetes environment, a deployment process might update the container image referenced by a Kubernetes workload.

For example, a Kubernetes deployment can be inspected using:

kubectl get deployments

The exact deployment command depends on how the organization's CI/CD system is designed.

Development, Staging and Production

Many teams use multiple environments before a change reaches production.

Development
Initial validation

→

Staging
Pre-production testing

→

Production
Real users

Not every organization uses exactly these environments, but separating deployment stages can reduce the risk of introducing untested changes directly into production.

Where Does Approval Fit?

Some organizations require an approval before production deployment.

For example:

Code
↓
Build
↓
Tests
↓
Staging
↓
Manual Approval
↓
Production

This type of workflow is commonly associated with Continuous Delivery rather than fully automatic Continuous Deployment.

What Happens When a Pipeline Fails?

A good CI/CD pipeline should provide feedback when a stage fails.

For example:

Commit
↓
Build ✓
↓
Unit Tests ✗
↓
Pipeline stops

The developer can inspect the logs, correct the problem and push another change.

This creates a feedback loop where problems can be discovered close to the point where they were introduced.

What Makes a Good CI/CD Pipeline?

A useful pipeline should be predictable, repeatable and easy to understand.

• Build from a known source revision.
• Use automated tests.
• Produce versioned artifacts.
• Keep credentials and secrets out of source code.
• Provide useful logs.
• Fail clearly when an important validation step fails.
• Use controlled deployment processes.
• Make deployments repeatable.

Why Secrets Should Not Be Stored in Git

CI/CD systems often need credentials for registries, cloud platforms or deployment environments.

These credentials should not normally be placed directly into application source code or committed into a Git repository.

CI/CD platforms commonly provide secure mechanisms for storing sensitive values and making them available to pipeline steps when required.

Never treat a Git repository as a password storage location. Credentials, tokens and private keys require appropriate secret-management controls.

How CI/CD Fits Into DevOps

CI/CD is one part of a broader DevOps approach.

Simplified DevOps Flow

Plan
↓
Code
↓
Build
↓
Test
↓
Release
↓
Deploy
↓
Operate
↓
Monitor
↓
Feedback

Automation helps connect these activities and can make software delivery more consistent.

CI/CD with Kubernetes

Kubernetes is often used as the deployment platform for containerized applications, while a separate CI/CD system handles building, testing and delivery.

A simplified workflow can be:

Developer
↓
Git Repository
↓
CI Pipeline
↓
Build Container Image
↓
Test
↓
Container Registry
↓
Kubernetes Deployment

This is one reason Git, Docker, CI/CD and Kubernetes are frequently discussed together when learning DevOps.

Practical CI/CD Example

Imagine a developer changes an application's login page.

1. The developer commits the change.
2. The commit is pushed to the remote repository.
3. The CI system starts the pipeline.
4. The application is built.
5. Automated tests run.
6. A container image is created.
7. The image is stored in a registry.
8. The deployment system updates the application.
9. Post-deployment checks confirm the application is operating as expected.

The exact implementation depends on the tools and architecture used by the organization.

CI/CD Interview Questions for Beginners

1. What does CI stand for?

CI stands for Continuous Integration.

2. What does CD stand for?

CD can mean Continuous Delivery or Continuous Deployment, depending on the context.

3. What is a CI/CD pipeline?

A CI/CD pipeline is an automated sequence of processes used to build, test, validate and potentially deploy software changes.

4. What happens if a test fails?

A pipeline can be configured to stop the affected workflow and report the failure so the problem can be investigated.

5. What is Continuous Delivery?

Continuous Delivery keeps validated changes ready for release, while a production deployment may still require an approval or decision.

6. What is Continuous Deployment?

Continuous Deployment automatically deploys changes that successfully pass the required pipeline checks.

7. Why is Git important for CI/CD?

Git provides the version-controlled source changes that commonly trigger and identify CI/CD workflows.

Frequently Asked Questions

Is CI/CD only for large companies?

No. CI/CD practices can be used by teams of different sizes. The complexity of the pipeline can be adjusted to the needs of the project.

Is CI/CD the same as DevOps?

No. CI/CD is an important part of many DevOps practices, but DevOps encompasses broader collaboration, automation, delivery and operational practices.

Can CI/CD deploy to Kubernetes?

Yes. A CI/CD workflow can build and validate application artifacts and then use an appropriate deployment mechanism to update Kubernetes workloads.

Does every pipeline automatically deploy to production?

No. Some pipelines stop after validation, while others use manual approvals or automatic production deployment depending on the organization's delivery model.

Practical CI/CD Exercise

You can understand the pipeline concept without immediately building a complex production system.

Create a small Git project and think through this workflow:

1. Create a Git repository.
2. Make a small application change.
3. Commit the change.
4. Imagine a build step.
5. Define at least one automated test.
6. Define what artifact would be produced.
7. Decide where that artifact would be stored.
8. Define how it would be deployed.
9. Define what checks would confirm a successful deployment.

This exercise helps you understand the architecture of a CI/CD pipeline before learning a specific CI/CD platform.

Key Takeaways

• CI stands for Continuous Integration.
• CD can mean Continuous Delivery or Continuous Deployment.
• A CI/CD pipeline automates parts of the software delivery process.
• Git commits commonly provide the starting point for pipeline execution.
• Builds and automated tests provide early feedback about code changes.
• Applications can be packaged as versioned artifacts.
• Containerized applications can produce Docker images as deployment artifacts.
• Container registries can store images used by deployment systems.
• Production deployment may be automatic or require approval.
• CI/CD is an important part of many modern DevOps workflows.

Related Topics

• Git for Beginners
• Docker Containers Explained
• Kubernetes Pods, Deployments and Services
• Kubernetes Services Explained
• Linux Commands for Beginners
• Container Registries
• DevOps Fundamentals
• Infrastructure Automation

Freshers Nation Editorial Note: This tutorial is intended as an educational introduction to CI/CD for students, freshers and IT professionals building software development, DevOps and cloud fundamentals. CI/CD implementations vary between organizations and tools.