Open Virtual Machine Spec (OVMS) v0.1

Mission

OVMS defines a portable specification for packaging, distributing, and running full-virtual-machine artifacts (disk layers, kernel/initrd, and optional RAM snapshots) with a small runtime contract. This enables any runtime to be a drop-in for orchestrators, supporting fast boot, layering, and OCI compatibility for distribution.

Quickstart

1. Create Manifest: Use the JSON schema in schemas/manifest.v1.json to define your VM artifact.
2. Build Artifact: Package kernel, initrd, disk layers, and RAM snapshot as OCI blobs (use tools like skopeo for OCI push).
3. Push to Registry: Push to OCI registry (e.g., Docker Hub, private).
4. Pull and Run: Use CLI ovm pull <ref> to fetch, then ovm run <ref> to start.
5. Snapshot: ovm snapshot <instance> -t <tag> to create RAM snapshot.
6. Integrate with your platform: Wire OVMS manifests into your orchestrator or runtime adapter to dispatch workloads to your chosen VMM.

Overview

OVMS reuses OCI for distribution (artifacts use OCI image manifests with custom media types and OCI 1.1 fields such as artifactType and subject). Artifacts are layered for efficiency: base disk + diffs + optional RAM snapshot for <10ms boots. Runtimes expose a minimal HTTP API for control. The specification is orchestrator- and runtime-neutral by design.

See rfc/ovms-v0.1.md for full spec and media types (e.g., application/vnd.ovms.manifest.v1+json).

Components

• Manifest: JSON describing artifact (see examples/ubuntu-manifest.json).
• Runtime Contract: HTTP endpoints for start/stop/snapshot/status (see rfc/ovms-v0.1.md).
• CLI: ovm tool for pull/run/snapshot (see cli/ovm).
• Adapters: Guidance for implementing runtime adapters (see spec/runtimes/).
• Hacks: OCI compatibility notes (see hacks/oci-compat.md).

Ecosystem (non‑normative)

• Community tools that aid OVMS adoption are listed under docs/ecosystem. These are optional and independent. See docs/ecosystem/README.md.

Security

• Sign manifests with Cosign (see docs/signing/README.md). Use OCI Referrers and subject to relate signatures to manifests.
• Runtimes use namespaces, seccomp for isolation.
• RAM snapshots opt-in with mlock for latency guarantees.

Limitations v0.1

• Linux x86_64 only.
• BIOS boot (UEFI v0.2).
• No GPU; basic devices (IVSHMEM).