Tauqeer Ahmad
A Complete Guide to GitHub Container Registry: From Basics to Intermediate Concepts

A Complete Guide to GitHub Container Registry: From Basics to Intermediate Concepts

Tauqeer Ahmad's photo
Tauqeer Ahmad
·

5 min read

Understanding Containers and Containerization

Before diving into the GitHub Container Registry (GHCR), it's crucial to grasp the fundamentals of containers and containerization, which are at the heart of modern software development and deployment practices.

What Are Containers?

At a high level, containers are a lightweight, portable, and efficient way to package and run applications. A container bundles an application and all its dependencies—like libraries, binaries, and configuration files—into a single package. This ensures that the application behaves the same, regardless of where it's deployed, whether on a developer’s laptop, a testing environment, or in production.

Think of a container like a "shipping container" for your software. Just as a shipping container can transport any type of goods across different types of transportation (ships, trucks, trains), software containers can move across different computing environments without worrying about the underlying infrastructure.

Why Containers? 🤔

Containers provide several benefits:

  1. Consistency: Because a container includes everything an application needs, it runs consistently in different environments, avoiding the "works on my machine" problem.

  2. Isolation: Each container runs in isolation from others, ensuring that issues like software dependencies and version conflicts are avoided.

  3. Efficiency: Containers are more lightweight than traditional virtual machines (VMs). While VMs virtualize the entire operating system (OS), containers share the host OS, allowing them to consume fewer resources.

  4. Scalability: Containers are easier to scale horizontally, making them ideal for modern cloud-native applications, which often need to handle varying levels of load.

  5. Supports OCI-compliant images: GHCR supports OCI-compliant images, OCI is standards for container formats and runtimes, making it versatile across platforms and orchestration systems.

What is Containerization?

Containerization is the process of packaging an application and its dependencies into containers. It simplifies development, testing, and deployment across environments.

What is GitHub Container Registry?

The GitHub Container Registry (GHCR) OR GitHub Packages is a service provided by GitHub to store and manage Docker container images. It's part of GitHub's suite of tools aimed at enabling developers to manage their entire DevOps lifecycle directly from their GitHub account. GHCR allows developers to push, pull, and manage Docker images, making it easier to distribute containerized applications alongside your GitHub repositories.

Key Features of GHCR

  1. Seamless GitHub Integration: GHCR is tightly integrated with GitHub repositories, allowing you to manage container images alongside your code and automate workflows using GitHub Actions.

  2. Public and Private Repositories: GHCR supports both public and private repositories for your container images, enabling flexible access control.

  3. Granular Permissions: Leverages GitHub’s permission model, allowing you to set precise access levels for users, teams, or the public.

  4. Docker CLI Compatibility: Fully compatible with Docker, so you can use familiar commands like docker push and docker pull.

  5. Free for Public Repositories: Public images are free to host, while private repositories follow GitHub’s pricing plans.

  6. Security Integration: Built-in security features like Dependabot alerts and image vulnerability scanning help ensure your containers are secure.

Let’s containerize an application and push it on GHCR.

  1. Considering you already have an application to containerize OR containerized already.

  2. The process starts from post-building the docker image, as we need to push it to GHCR.

  3. Now create a Personal Access Token (PAT) from the settings here with the scope of read, write and delete packages.

  4. Let’s login to GitHub Container using PAT (Personal Access Token) security by the following command.

     export CR_PAT=<YOUR_TOKEN>

    Replace <YOUR TOKEN> with the token generated by GitHub to copy and paste.

     echo $CR_PAT | docker login ghcr.io -u USERNAME --password-stdin

    Simply export your PAT Token and use the above-given command to Docker Login to GitHub Container Registry.

    Hope it’s a success till here.

  5. Considering I've got a project for Etherlink website based on Next.js and here I’ve already containerized it BUT looking forward to push it to GHCR.

    Here, image name is etherlink-website:latest, here latest stands for the tag.

  6. Let’s tag the image etherlink-website:latest with GHCR’s image name pattern*.* Use this pattern ghcr.io/NAMESPACE/IMAGE_NAME:latest

     docker tag etherlink-website:latest ghcr.io/tauqeerahmad5201/etherlink-website:latest

    Now, the image is renamed to ghcr.io/tauqeerahmad5201/etherlink-website:latest

  7. Here comes the time to push it on the container registry.

docker push ghcr.io/tauqeerahmad5201/etherlink-website

Done! We’ve successfully pushed our docker image over the GitHub Container Registry. Now anyone can pull the image and use it wisely.

Checkout the image from here:

Diving deep into images and their compatibility:

Multi-platform Image Support

Multi-platform images allow your containers to run on different CPU architectures (e.g., ARM64, AMD64).

Why it's important: As applications scale across diverse environments, having architecture-independent images ensures your containers work on both cloud and edge devices.

How to build it? Well we can use buildx to build a multiplatform image. Given below is the syntax but needs to install buildx to use it.

docker buildx build --platform linux/amd64,linux/arm64 -t ghcr.io//: --push .

Versioning and Tagging Strategies

  • Versioning best practices:

    • Use tags like latest for stable production-ready versions.

    • Use semantic versioning (v1.0.0, v1.0.1) to differentiate between versions.

  • Why Tagging is Important: It helps identify different builds and ensures you're using the right image for each environment (development, staging, production).

Automated Image Publishing with GitHub Actions

  • What is GitHub Actions?: A CI/CD automation tool that helps automate builds, tests, and deployments.

  • Why use it with GHCR?: Automating image building and pushing helps speed up your release cycle.

Conclusion

  • GHCR is a powerful tool for managing containerized applications with tight integration into GitHub's ecosystem. 🙌🏻

  • From basic image management to advanced multi-platform support and CI/CD automation, GHCR can streamline your DevOps pipelines. 🤝

  • Whether you're an individual developer or part of a large team, GHCR provides security, ease of use, and seamless integration with GitHub. 😌

  • Explore further by diving into GitHub’s documentation or experimenting with more advanced setups in your projects. 🤗

GitHubDevopsDevops articlescontainersDocker