Open Virtualization FormatEdit
Open Virtualization Format (OVF) is an open standard for packaging and describing virtual machines and virtual appliances, designed to improve portability and interoperability across different virtualization platforms and cloud environments. Developed under the auspices of the DMTF (Distributed Management Task Force), OVF provides a machine-readable description of a virtual system along with the necessary disk images and metadata to deploy that system on diverse hypervisors. In practice, OVF commonly appears as a set of files with a descriptor file (.ovf), one or more disk image files (for example, VMDK or VHD), and, optionally, a manifest (.mf) and certificate (.cert) for integrity and authenticity. A single-file distribution wrapper known as an OVA (Open Virtual Appliance) package is also widely used to simplify distribution.
OVF arose from a collaborative effort to standardize the way virtual machines and appliances are packaged so that a workload created on one platform could be moved to another with minimal reconfiguration. The standard is intended to cover both the portable description of hardware resources (CPU, memory, storage, and network interfaces) and the software environment (operating system, installed applications, and licensing metadata). By codifying these aspects, OVF aims to reduce vendor lock-in and streamline deployment in heterogeneous environments, including internal data centers and public clouds.
History and governance
OVF was developed through the work of industry participants coordinated by the DMTF. It reflects a consensus around how virtualization artifacts should be described and exchanged among tools and platforms. Since its initial release, OVF has seen revisions and extensions to address evolving virtualization technologies, including more complex virtual hardware configurations, enhanced network definitions, and better support for cloud-centric workflows. These updates have been accompanied by broad vendor support and ongoing discussions about how best to balance expressiveness with simplicity so that the format remains broadly usable across hypervisors and cloud services.
Technical overview
An OVF package is organized around a few core components:
- The OVF descriptor (.ovf) – an XML document that describes the virtual system, its hardware requirements (VirtualHardwareSection), operating system details (OperatingSystemSection), network topology (NetworkSection), and software components (ProductSection, VirtualSystem, and related structures).
- References and files – a list of any ancillary files referenced by the descriptor, typically disk images such as VMDK or VHD files, and other resources.
- Optional manifest (.mf) – a text file containing cryptographic hashes for the files in the package, enabling integrity checks. The accompanying certificate (.cert) can provide a signature for authenticity.
- Packaging formats – OVF packages are often distributed as a set of files in a directory, or as a single-file OVA archive that bundles the descriptor, disks, and metadata together.
Key features described by OVF include: - Virtual hardware configuration (CPU, memory, storage, and I/O settings) defined in a platform-agnostic way. - Network definitions that map to logical networks rather than vendor-specific adapters. - Operating system and application metadata that can guide deployment and configuration. - The ability to reference multiple disk images and organize them within a single package.
Because OVF is an open standard, its descriptor is designed to be interpreted by a wide range of hypervisors, including major players in the virtualization ecosystem. Implementations exist or are planned across systems from mainstream platforms such as VMware and Hyper-V to open-source stacks built on KVM and OpenStack.
Adoption, compatibility, and workflows
OVF is widely supported as a means to import and export virtual machines and appliances, but practical interoperability depends on the degree to which a given hypervisor or cloud platform implements the standard’s features. Commonly supported capabilities include:
- Importing OVF packages into hypervisors such as VMware products, Hyper-V, KVM, and VirtualBox.
- Exporting VMs or appliances to OVF/OVA formats for distribution or archival.
- Use of the OVF descriptor to automate deployment steps and to provide a portable blueprint for the virtual environment.
In cloud environments, OVF is used as a bridge between on-premises virtualization and public clouds. Tools such as the VMware OVF Tool help convert between OVF/OVA formats and platform-specific representations. For Linux-centric workflows, components of the OpenStack ecosystem and related tooling provide native support for importing OVF-described workloads or converting them into compatible images for storage and deployment.
Despite broad support, some features of OVF are implemented unevenly across platforms. For example, certain hardware virtualization options or network configurations described in an OVF package may map cleanly on one hypervisor but require adaptation on another. This reality fuels ongoing discussions about standardization versus platform-specific optimizations, and it explains why many practitioners maintain a portfolio of tooling to handle different environments and migration scenarios.
Variants, extensions, and modern relevance
A central variant of OVF is the Open Virtual Appliance, or OVA, which packages the OVF descriptor together with disk images in a single tar archive for convenient distribution. The separation between the descriptor and the disk images in OVF (as opposed to bundling in OVA) offers flexibility for updating or reusing components without reconstructing the entire bundle.
Other standard artifacts associated with OVF include the mf manifest and optional cert certificates, which support integrity checks and authenticity verification. Some deployments also leverage ProductSection metadata to carry vendor- or appliance-specific licensing and configuration details.
As virtualization technology evolves and containerization grows in prominence, OVF remains relevant for workloads that require full VMs rather than container images. While containers are increasingly popular for lightweight, portable deployment, many enterprises still rely on OVF/OVA workflows for traditional virtual machines, multi-VM appliances, and complex operating-system stacks. In this context, OVF continues to serve as a stable, interoperable packaging and description format that complements other packaging approaches in the ecosystem.
See also: