The CNCF Technical Oversight Committee (TOC) has voted to accept Longhorn as a CNCF incubating project.

Longhorn is a distributed block storage system for Kubernetes, designed to run on top of different types of physical storage devices, infrastructures, and architectures. It is built on Kubernetes for workloads running on Kubernetes. Longhorn’s control plane is based on the controller design pattern and leverages dynamic pod management to provision its data plane communication stack.

Longhorn is used in production by organizations like Cerner, a health information technology company using Longhorn for persistent storage and highly available data replication; Tribunal Regional Eleitoral do Pará, the regional electoral court of the state of Pará, Brazil, which uses Longhorn as the storage backend for Prometheus and other tools; and Tyk, an open-source API and service management platform which uses Longhorn to back hundreds of dynamically provisioned cluster nodes. 

“Longhorn has grown from strength to strength since its inception, having helped thousands of Kubernetes users solve their storage challenges,” said Sheng Liang, president of Engineering and Innovation at SUSE and CNCF TOC Member. “Longhorn’s latest promotion to incubation is a testament to the community’s support, and I’m excited to see what the future holds as it continues its growth within CNCF. I am also proud of the Longhorn developers who have worked tirelessly to address the needs of the community by refining, building, and delivering new innovative features and improvements with each release.”

Longhorn joined CNCF as a sandbox project in October 2019. Since then, Longhorn has seen exceptional growth, increasing from 200 contributors from 30 companies to more than 800 contributors from over 120 companies. The number of committers increased from 14 from 3 companies to more than 70 committers across 13+ companies. The number of nodes running Longhorn worldwide increased by 10x from 2,700 to over 34,000.

Longhorn already integrates with several other projects in the CNCF community. Its components are implemented by gRPC to communicate with each other. Longhorn also integrates with Prometheus to provide metric endpoints and pre-built metrics dashboards and leverages Helm to deliver software to users.

“I’ve been working on the Longhorn project for the last six years, and it’s been humbling to see the Kubernetes and cloud native ecosystem widely adopt the project,” said Sheng Yang, Engineering Lead for Longhorn. “Beyond increasing the usability and stability of Longhorn, I am looking forward to the result of the performance improvement work we’re doing. I’m excited to be a part of CNCF family and to grow alongside other great CNCF projects.”

“Distributed block storage for Kubernetes is particularly important for cloud native environments where things may be dynamic and transient in nature,” said Chris Aniszczyk, CTO of CNCF. “Projects like Longhorn are helping to create a place where cloud native applications have more resilient options when it comes to highly available persistent storage for Kubernetes. We look forward to continuing to cultivate the Longhorn project in CNCF.”

Main Components:

  1. Enterprise-grade distributed storage with no single point of failure
  2. Incremental snapshot of block storage
  3. Backup to secondary storage (NFSv4 or S3-compatible object storage) built on efficient change block detection
  4. Recurring snapshot and backup
  5. Automated non-disruptive upgrade. You can upgrade the entire Longhorn software stack without disrupting running volumes!
  6. Intuitive GUI dashboard

Notable Milestones:

  • 800+ contributors from 120+ companies
  • 70+ committers from 13 organizations
  • GitHub: increased from 600+ stars to 3,000+ stars
  • Slack channel: increased from 200+ members to 1,500+ members
  • 34,000+ nodes running Longhorn 

The Longhorn roadmap includes enhanced API, cloud provider enhancements, application, highly available RWX storage, storage network, and more, which can be seen in Longhorn Priorities. We recently announced Longhorn v1.2, which included volume & backup encryption, automatic replica rebalancing, policy-based backup rules, volume clone support, and more.

“There are two major things that I am looking forward to for Longhorn,” said David Ko, Senior Engineering Manager for Longhorn. “First, I’m excited to see the project include enriching data services and improving the data path performance. Second, and most important, I’m excited to see the project grow and be embraced by the wider community. CNCF is a great open source incubator, and the support from the community helps us as maintainers to build better technology and promote innovation, and it encourages us to innovate and enrich the cloud native world.”

As a CNCF-hosted project, joining incubating technologies Argo, Buildpacks, Cilium, CloudEvents, CNI, Contour, Cortex, CRI-O, Crossplane, Dragonfly, emissary-ingress, Falco, Flagger, Flux, gRPC, KEDA, KubeEdge, NATS, Notary, OpenTelemetry, Operator Framework, SPIFFE, SPIRE, and Thanos, Longhorn is part of a neutral foundation aligned with its technical interests, as well as the larger Linux Foundation, which provides governance, marketing support, and community outreach. For more information on maturity requirements for each level, please visit the CNCF Graduation Criteria.