Project Journey Report
Harbor is a self-hosted cloud native registry that stores, scans, and signs content such as container images as well as OCI artifacts, including Helm charts. It extends the open source CNCF Distribution project and adds useful functionality, such as user management, security, activity auditing, and role-based access control (RBAC). Harbor supports image replication between registries, enabling hybrid-cloud and multi-cloud interoperability.
One feature Harbor users benefit from is the registry’s proximity to the build-and-run environment, which improves image-transfer efficiency. Also, its scanning capabilities help ensure that images are free from vulnerabilities early in the development and deployment processes. Since Harbor is self-hosted, users can run the registry in their private, on-premises environment rather than in a public cloud. This may be desirable for organizations with stringent privacy or security standards.
Harbor was created at VMware China in 2014 and initially open sourced in 2016. It is the first open source registry compliant with the specifications of OCI (Open Container Initiative) — a Linux Foundation project focused on creating open industry standards around container formats and runtimes.
In this project journey report, we guide you through the remarkable growth journey Harbor has experienced under CNCF. We can’t attribute every data point to specific inputs, but we can document and explore the correlations in search of successful decisions and actions. This report is part of a series of project journey reports published by the CNCF.
NOTE: These statistics were collected with the DevStats tool, which CNCF built in collaboration with CNCF project communities. When we refer to “Contributor,” we mean somebody who made a review, commented, committed, or created a PR or issue.
One of the most important events for Harbor was joining CNCF. It is a trusted organization; it is supported and trusted by many businesses and developers. So anyone considering hosting for their Docker or OCI images immediately sees that Harbor is an open source registry hosted by CNCF; that’s often why they consider using Harbor. I think that’s one benefit we got from joining CNCF.
Staff Engineer at VMware, Harbor Maintainer
Harbor has been adopted by organizations across the globe including CERN, where Harbor plays a critical role in the cloud native infrastructure, enabling smooth collaboration from more than 170 different sites.
Harbor is a crucial piece in our growing cloud native infrastructure. It offers an open and community driven solution providing the required high availability and performance, with a strong security focus and features such as automated vulnerability scans, artifact signing, among others. With over 170 sites collaborating on CERN’s computing grid all over the world, automated replication to and from external registries is also a key feature along with pull-through caches that significantly minimize the deployment time for our popular workloads and circumvent rate limits set by public registries.
Computing Engineer, CERN
Harbor plays a key role for hundreds of companies of all sizes leveraging container-based Infrastructure on OVHcloud. We made Harbor accessible to anyone, through our Managed Private Registry service, with full OCI support and advanced security. Because we believe in reversible standards and open source, we are proud to have multiple active contributors and maintainers of the project, playing a key role in continuous improvement of Harbor and its Kubernetes operator.
Harbor has increased velocity and adoption thanks to healthy coordination and shared vision among its major vendor and end-user contributing communities. Since joining CNCF, Harbor has tallied contributions from more than 688 organizations.
The top contributing company by far is VMware, with a cumulative 72% of contributions to date. DoiT International and Consumer Physics occupy the second and third place, respectively, the former with 7% of contributions and the latter with 2%.
VMware accounted for 76% of contributions before the project joined CNCF in 2018. While its percentage of contributions has declined somewhat over time, its gross number of contributions has increased. Today, contributors include world-leading tech enterprises, like Samsung, Hewlett Packard Enterprise, and NetEase, as well as startups and fast-growing mid-size companies, including Aqua Security, Caiyun Technology (Caicloud), and Rafay Systems. These factors indicate a healthy dynamic, where project originators have contributed prolifically while encouraging other organizations to increase their contributions, sharing stewardship and growing the community.
Since joining CNCF in July 2018, the number of contributing companies has risen from 142 to 762, a 437% increase. This growth corresponds to a rise in individual contributors from 924 when it joined to 6,090 today, representing a 560% increase.
The diversity of company contributors, and the healthy balance of vendor<->end user input, continues to fuel growth and give users confidence in choosing Harbor as their registry for container images and artifacts.
Before joining CNCF, we mostly promoted Harbor inside China. But globally, we still needed visibility and channels to promote the project. CNCF came out as an important channel for us to promote the project to the global community and users.
Haining (Henry) Zhang
Chief Architect and Director of Cloud Native Lab at VMware China,
Harbor Founder and Maintainer
Cumulative growth of Harbor contributions by company Q1 2016 – Q3 2023
Percentage breakdown of Harbor contributions by company Q1 2016 – Q3 2023
Cumulative growth of contributing companies Q1 2016 – Q3 2023
Cumulative growth in contributors Q1 2016 – Q3 2023
Top Contributing Countries
Percentage contributions to Harbor by country Q1 2016 – Q3 2023
The importance of velocity is that it allows the CNCF, the Linux Foundation, and other stakeholders to track trends and technologies resonating with developers and end users. By observing the velocity of various projects, we can understand which projects are growing, which are maturing, and which are cultivating large communities. This information can then be used to guide decisions and strategies.
Monthly velocity of Harbor Q1 2016 – Q3 2023
Based on velocity metrics since joining CNCF, Harbor appears set to continue growing at a robust pace.
One way we track developer velocity (defined by us) is with a simple formula: commits + PRs + issues + authors. We also look at cumulative numbers of contributors throughout Harbor’s history. Both illustrate that Harbor’s formula of multiple vendors and end users creates healthy grassroots support.
Growth of Harbor pull requests, code commits, issues, & authors Q1 2016 – Q3 2023
After Harbor graduated from CNCF, many, many developers from the community were interested in contributing to the project. So the Harbor team set up many different work groups for specific topics, and if anyone from the developer community is interested in any of these groups, they can join that group and work together with the project maintainers.
Senior Engineering Manager at VMware,
Harbor Core Contributor
The more a project’s community participates in education, events, and sponsorship, the healthier the project tends to be.
CNCF’s flagship KubeCon + CloudNativeCon events in North America, Asia, and Europe have spotlighted Harbor since 2018. Overall, Harbor has been the subject of 52 talks, sessions, meetings, and workshops at these events, attended by tens of thousands annually. CNCF also hosted a special co-located event, CNCF Harbor China Community Reception & Award Ceremony, at KubeCon + CloudNativeCon China in 2018.
Harbor holds biweekly community meetings to discuss project updates, listen to feedback from the Harbor community, and collect end-user requirements and use cases for the development of new features.
Harbor also offers two distribution lists, one for users and one for developers. The user email group regularly receives news, features, and releases, as well as opportunities to provide suggestions and feedback; the developer group receives updates related to development and contribution.
In 2020, Harbor maintainers and contributors released a book titled “The Authoritative Guide on Harbor” Now available in both English and Chinese editions, the book is geared towards cloud native architects, DevOps engineers, developers, end users, and anyone who wants to learn more about the project and how it works.
Harbor has two dedicated Slack channels within the CNCF Slack workspace, one for end users and one for developers. Combined membership totals 4,087.
Being able to share what you’re working on, on stage, at KubeCon + CloudNativeCon brings so much power and motion into what you’re doing and how people interact with you and with the project. I think that there’s no other way to do that so effectively.
Senior Open Source Community Manager at VMware,
Upon Harbor joining CNCF in 2018, we’ve worked diligently to spread awareness of the project and expand its community through two core principles:
- Solving real problems and being genuine with our audiences.
- Listening to all inputs from vendors and end users to maintain balance and generate excitement.
Cloud native projects can’t exist without robust documentation for educating new users and helping existing users solve problems. A healthy velocity of documentation changes is a great signal for the health of a project’s community.
To date, more than 160 contributors from many backgrounds and motivations have added to and polished Harbor’s documentation.
NOTE: Documentation for Harbor is authored in .md files. CNCF uses the DevStats tool to automatically collect and count statistics of all relevant .md files in the Harbor repositories in GitHub.
Growth in participation in Harbor project documentation Q1 2016 – Q3 2023
Cumulative growth of Harbor project documentation commits Q1 2016 – Q3 2023
CNCF is committed to fostering and sustaining an ecosystem of open source, vendor-neutral projects by democratizing state-of-the-art software development and deployment patterns to make technology accessible for everyone.
We hope this report is a useful window into how CNCF fosters and sustains the growth of Harbor, its team, and the diverse community of individuals and organizations using and shaping the project.