Citrix Systems Open Virtualization Format (OVF): Package and Distribute Virtual Appliances Effectively

Consider using XVA format to:

•Share VMs with versions of XenServer earlier than 6.0

•Import and export VMs from a script with a CLI

11.1.1. Open Virtualization Format (OVF and OVA)

OVF is an open standard, specified by the Distributed Management Task Force, for packaging and distributing a virtual appliance consisting of one or more VM(s). For further details about OVF and OVA formats, see the following:

•Knowledge Base Article CTX121652: Overview of the Open Virtualization Format

•Open Virtualization Format Specification

Note:

In order to import or export OVF or OVA packages, you must be logged in as root or have the Pool Administrator Role Based Access Control (RBAC) role associated with your user account.

An OVF Package is the set of files that comprises the virtual appliance. It always includes a descriptor file and any other files that represent the following attributes of the package:

Attribute	Description
Descriptor (.ovf)	The descriptor always specifies the virtual hardware
	requirements of the package. It may also specify other
	information, including:
	•	Descriptions of virtual disks, the package itself, and
		guest operating systems
	• A license agreement
	•	Instructions to start and stop VMs in the appliance
	•	Instructions to install the package
Signature (.cert)	The signature is the digital signature used by a public
	key certificate in the X.509 format to authenticate the
	author of the package.
Manifest (.mf)	The manifest allows you to verify the integrity of the
	package contents. It contains the SHA-1 digests of
	every file in the package.
Virtual disks	OVF does not specify a disk image format. An OVF
	package includes files comprising virtual disks in
	the format defined by the virtualization product
	that exported the virtual disks. XenServer produces
	OVF packages with disk images in Dynamic VHD
	format; VMware products and Virtual Box produce
	OVF packages with virtual disks in Stream-Optimized
	VMDK format.

OVF packages also support other non-metadata related capabilities, such as compression, archiving, EULA attachment, and annotations.

Note:

When importing an OVF package that has been compressed or contains compressed files, you may need to free up additional disk space on the XenServer host in order to import it properly.

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