OVFs

OVF stands for Open Virtualization Format. It is an open standard for packaging and distributing virtual appliances and virtual machines. Developed by the Distributed Management Task Force (DMTF), OVF aims to improve portability and interoperability across virtualization platforms by providing a common description of a VM’s software, hardware requirements, and deployment configuration.

An OVF package can be a directory containing an XML descriptor with the .ovf extension, one or more virtual disk images (for example .vmdk, .vhd, or .img), and an optional manifest file that contains checksums. A single-file OVA is a tar archive that bundles the OVF descriptor, disk images, and the manifest. The package may also include certificates for signing. The OVF descriptor describes one or more VirtualSystem or VirtualSystemCollection objects, each with a VirtualHardwareSection listing resources such as CPU, memory, network interfaces, and attached disks. It uses sections such as OperatingSystemSection, ProductSection, NetworkSection, and DeploymentOptionSection to convey guest OS details, product information, networking, and deployment options.

Structure and features: OVF is an XML-based format that enables detailed hardware and software descriptions, network configurations, and dependencies. It supports multiple hardware profiles, various disk formats, and references to external resources. A manifest file provides integrity verification through checksums.

Usage and interoperability: OVF is designed for import and export across compatible hypervisors and cloud platforms, including VMware, Hyper-V, KVM, VirtualBox, and Xen. By standardizing the packaging and description of virtual appliances, OVF enhances portability, reduces vendor lock-in, and facilitates large-scale deployment and distribution of virtual machines and appliances.