History
Origin
Longhorn started at Rancher Labs. The data plane came first: the longhorn/longhorn-engine repository was created on 2016-04-08, and the umbrella longhorn/longhorn repository followed on 2017-04-14. Rancher introduced it publicly in April 2017 as a new distributed block storage system built for containers, with co-founder Sheng Liang presenting the idea (source 5, source 4).
The lineage matters for reading the code. The storage controller existed before Kubernetes integration; the control plane (longhorn-manager) was layered on top later as a set of CRDs and controllers. That is why the manager README.md describes itself only as "Manager for Longhorn" and why the data plane lives in sibling repositories rather than in the manager itself.
Timeline
| Year | Milestone |
|---|---|
| 2016 | longhorn-engine repository created (2016-04-08), the original storage controller. |
| 2017 | longhorn/longhorn umbrella repository created (2017-04-14); Rancher announces Longhorn publicly. |
| 2019 | Donated to CNCF and accepted as a Sandbox project (2019-10-11) at version 0.6.2. |
| 2020 | Rancher is acquired by SUSE; SUSE becomes the primary sponsor. |
| 2021 | CNCF TOC promotes Longhorn to Incubating (2021-11-04). |
| 2026 | v1.12.0 released (2026-06-02), the latest release at the time of this deep-dive. |
How it evolved
When Longhorn was donated to the CNCF Sandbox in October 2019, the v0.6.2 release already shipped snapshots, backup and restore, live upgrade, disaster recovery, one-click install, and a GUI (source 6, source 3). The acquisition of Rancher by SUSE in 2020 shifted sponsorship; the commercial product is now "SUSE Storage (powered by Longhorn)" (source 7).
The largest engineering shift visible in current source is the v2 Data Engine. The original v1 engine is built on iSCSI and tgt. Recent releases add a v2 data engine built on SPDK. The branching is pervasive in the code: types.IsDataEngineV2(volume.Spec.DataEngine) gates separate teardown paths (controller/volume_controller.go:365), and a ublk frontend appears in the volume CRD alongside the older blockdev and iscsi frontends (k8s/pkg/apis/longhorn/v1beta2/volume.go:256).
Where it stands now
Longhorn promoted to CNCF Incubating on 2021-11-04. The CNCF cited growth since donation: from 200 contributors across 30 companies to 800+ across 120+ companies, from 14 committers across 3 companies to 70+ across 13+ companies, and from 2,700 to 34,000+ running nodes (source 3). The latest release at the time of writing is v1.12.0 (2026-06-02); the commit read here, 3b8885a, is a later point on master. SUSE remains the primary corporate sponsor.