This is the first part in a three part series on selecting and deploying a Private Container Registry. In this post, we’ll be looking at why organizations require private registries, and some of the leading options available today.
As enterprises increasingly adopt containerization technologies like Docker and Kubernetes, a reliable and secure container registry becomes paramount. A container registry is a repository for storing and distributing container images, serving as a central hub for managing, versioning, and sharing containerized applications. While public container registries like Docker Hub offer convenience, there are compelling reasons to consider deploying a private container registry. In this article, we’ll explore the importance of a private container registry and the top use cases for its adoption.
We will also look at some of the choices available to deploy a private registry.
What is a Container Registry?
A container registry is a repository for storing and managing container images. Container images are used to package and deploy applications that are built using Docker. Most of the container registries go beyond storing just the container images by supporting OCI artifacts.
OCI stands for Open Container Initiative, which is a non-profit organization that develops open standards for container formats and runtimes. OCI artifacts can be of any type, including container images, software packages, and documentation. For example, the Acorn container management framework packages each Acorn file into a format that includes Docker images, configuration, and deployment specifications into a single OCI artifact.
OCI registries are designed to be highly interoperable, which means that the artifacts can be pushed and pulled from any OCI registry. This approach makes it easy to share images and artifacts with others and to use images from different sources.
A unique name and a digest identify OCI artifacts. The name is a human-readable string, while the digest is a cryptographic hash of the artifact’s contents. This ensures that artifacts can be uniquely identified and that they cannot be tampered with.
Public container registries, such as Docker Hub, are an excellent option for storing and sharing container images and OCI artifacts with the public. However, a private container registry is a better choice for many organizations.
Building a Case for the Private Registry
Here are the top reasons why enterprises invest in a private registry:
Security: A private container registry can be configured to provide a higher level of security than a public registry. For example, a private registry can be configured to require authentication and authorization for access.
Compliance: In some industry verticals, such as financial services and healthcare, strict compliance requirements must be met. A private container registry can help organizations to meet these requirements by providing a more secure environment for storing and managing container images.
Control: A private container registry gives an organization more control over the container images that are stored and used. For example, an organization can use a private registry to store images that are not available in public registries. This approach ensures that only the DevOps teams deploy only trusted versions of the OCI artifacts.
Performance: A private container registry can be located on-premises, improving performance for applications deployed using containers.
Offline Access: One of the key advantages of a private registry is that the images are available locally without the need to pull the images from a repository hosted in the cloud or at a remote location. This configuration enables air-gapped deployment of workloads without reliance on the Internet.
Top Use Cases for a Private Container Registry
- Enterprise Software Delivery: Private container registries are essential for organizations developing and delivering software applications internally. By using a private registry, companies can maintain control over their software supply chain, ensuring consistent and secure delivery of containerized applications across development, testing, and production environments. Additionally, private registries can manage custom base images, proprietary libraries, and third-party dependencies, streamlining the development and deployment processes.
- Continuous Integration and Delivery (CI/CD): Private container registries are vital in CI/CD pipelines. By storing and versioning container images in a private registry, organizations can reliably build, test, and deploy containerized applications at scale. The registry acts as a single source of truth, allowing developers and automated processes to access the latest version of container images for seamless integration, testing, and deployment into production environments.
- IoT and Edge Computing: The proliferation of Internet of Things (IoT) devices and edge computing architectures introduces unique challenges in managing software updates and deployments. A private container registry enables organizations to store and distribute container images optimized for specific hardware architectures, facilitating efficient software deployment and version control at the edge. With a private registry, organizations can manage the containerization of applications and deploy updates to IoT devices or edge nodes in a controlled and reliable manner.
Choices to Deploy a Private OCI Registry
There are several different ways to deploy a private container registry. Let’s look at some of the most popular choices.
Docker Registry server is an open source OCI registry that can be used to store and share container images. However, it is not as scalable and reliable as the Docker Hub, which is hosted and managed by Docker, Inc.
Quay is a private container registry that is primarily maintained by Red Hat. It offers several features designed to make it easy to manage private container images, including authentication, authorization, and security scanning. Project Quay is the free and OSS flavor of the registry, while Red Hat Quay is a commercial product.
JFrog Artifactory is a commercial artifact repository that can be used to store and manage a variety of artifacts, including container images. Artifactory offers several features designed to make it easy to manage private container images, including authentication, authorization, and security scanning.
The GitLab Container Registry is a secure and private registry for container images. It’s built on open source software and completely integrated within GitLab. Use GitLab CI/CD to create and publish images. Use the GitLab API to manage the registry across groups and projects.
Harbor is an open source private container registry that was developed by VMware, which donated it to the Cloud Native Computing Foundation (CNCF). Harbor, a CNCF Graduated project, offers several features designed to make it easy to manage private container images, including authentication, authorization, and security scanning.
The best option for an organization will depend on its specific needs and requirements. For example, an organization that needs to store many images with minimum latency may want to use a private registry hosted on-premises. An organization that needs to meet strict compliance requirements may want to use a private registry that offers features such as image encryption and access control.
In the next part of this series on the private registry, I will walk you through the steps involved in configuring and securely deploying the open source Harbor registry in an on-premises environment. Stay tuned. To learn more about how to build containerized applications quickly and effectively, check out the Acorn getting started guide.
Janakiram is a practicing architect, analyst, and advisor focusing on emerging infrastructure technologies. He provides strategic advisory to hyperscalers, technology platform companies, startups, ISVs, and enterprises. As a practitioner working with a diverse Enterprise customer base across cloud native, machine learning, IoT, and edge domains, Janakiram gains insight into the enterprise challenges, pitfalls, and opportunities involved in emerging technology adoption. Janakiram is an Amazon, Microsoft, and Google certified cloud architect, as well as a CNCF Ambassador and Microsoft Regional Director. He is an active contributor at Gigaom Research, Forbes, The New Stack, and InfoWorld. You can follow him on twitter.
Header photo by 🇸🇮 Janko Ferlič on Unsplash