Daniel P. Berrange wrote:
> 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.
Agreed. The open-ovf project was an attempt at such a layer, but AFAIK
it is a dead project. As I recall, the code was rather complex for the
task, and is likely lagging the current OVF specs, but it might be
useful for reference
https://gitorious.org/open-ovf
Regards,
Jim
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