Re: [libvirt] RFC: Enable Libvirt to handle OVA installation

On Wed, Dec 05, 2012 at 01:50:05PM -0800, Ata Bohra wrote: > This is a proposal to enhance Libvirt library to handle OVA package installation. OVA: > OVA is one of the widely accepted and consortium defined/maintained format for > Virtual Machine distros. Technically it is a tar file with three main components: > 1. VMX descriptor (XML file defining virtual machine specifics such as: virtual hardware etc. > 2. VMDKs in a compressed format. > 3. Manifest file. Proposal: > 1. Expose a public API method to allow an application to invoke OVA installation with > a file pointer to OVA file. > 2. OVA util file: > This file understands the OVA formats and rips out the given package to extract specific information: > 2.1. int get_vmx(char *vmx): > method can return VMX descriptor associated with a given OVA file. > 2.2. int get_vmdks(struct ova_type *ova): > method that seek the OVA file and populate ova_type struct which may look like; > typedef struct disk_list_tag { > char *file_name; > off_t file_size; > off_t file_offset; > struct disk_list_tag *next; > }; > > typedef struct ova_type { > int num_vmdks; > ova_list *head; > } > 2. Hypervisor specific changes: > It can be done in more than one way: > 2.1: Enhance hypervisor driver function to implement hypervisor specific routines to > perform OVA installations. > 2.2.: Append a new driver to handle OVA installation such as virOvaDriver, main routines can be: > open() : parse OVA using util functions. > close() > list_disk(): may display disk names > install() (Please suggest if there can be more routines to this driver, it can be enhanced later as well). > It is possible to design this driver to handle OVA parsing as well, but I think keeping it in > 'util' may make that code available for all hypervisors given OVA format does not change per > hypervisor. I'm inclined more towards 2.2 design as it is more generic and provides room for furture extensions. Looking forward for comments/suggestions. Thanks!Ata > I really don't want to see OVA support integrated into libvirt APIs. libvirt aims to only provide the mechanism for virt management. OVA, however, is a policy based approach to virt management. As such it should be done by a layer above libvirt, which simply makes use of the libvirt mechanism to accomplish its work.