MiddleMedium2-4 hoursCI/CD

Build a Docker Image in GitHub Actions

Create a CI workflow that builds a Docker image automatically on push and validates the image build process.

GitHub ActionsDockerGit

Goal

Connect CI concepts with container workflows used in real DevOps pipelines.

Skills You Practice

CI/CDGitHub ActionsDockerAutomation

Architecture

GitHub repository

Workflow file under .github/workflows

GitHub Actions runner

Docker build step creating image artifact

Run logs used for validation

Phases

Prepare repository

Use a project that includes a valid Dockerfile.

Add Dockerfile to repo

Confirm the image builds locally

Push the project to GitHub

Create workflow

Define the workflow that checks out the repo and builds the image.

Create workflow YAML

Configure trigger on push

Add checkout step

Add docker build step

Validate pipeline

Trigger the workflow and inspect the run logs.

Push a change

Open GitHub Actions

Review build logs

Document the workflow result

Core Steps

Add a Dockerfile to the project.

Create a GitHub Actions workflow.

Add a Docker build step.

Push changes to trigger the workflow.

Review run logs.

Verification

Workflow runs automatically on push

Docker build step succeeds

Logs clearly show build process

README explains the CI container build flow

Deliverables

GitHub Actions workflow

Dockerfile

README with CI explanation

Interview Value

Shows that you can automate container builds in CI and understand the connection between GitHub Actions and Docker workflows.

Common Mistakes

Workflow path or YAML indentation errors

Invalid Docker build context

Using a broken Dockerfile without local testing first

Not reviewing logs after pipeline failure

Next Upgrade

Push the built image to Docker Hub or ECR

Add image tagging by commit SHA

Run tests before build

Split CI into multiple jobs