Anyone contemplating a move to the cloud has, by now, paused for a moment to wonder how to escape from their chosen provider of numinous computing.
They've done so because shunting a virtual machine (VM) and its workloads into the cloud may seem like a fine idea today, but there are any number of reasons one may wish to place it elsewhere in future. A few come easily to mind: your cloud provider could go titsup or become unacceptably unreliable; you may want to bring the workload back home on a matter to meet a particular need; another cloud could offer better prices, or; you might like the idea of moving the VM for disaster recovery or follow-the-moon electricity-price-saving-fun.
Whatever the reason, the ability to create a virtual machine that can be read and used by any other cloud or hypervisor seems a very reasonable idea.
After years of being taught to be wary of proprietary anything, users are now confronted with closed VM formats, giving them good reason to want something portable. For ISVs a bundle once, run anywhere, regime surely appeals too.
For all the reasons and more outlined above, the distributed management task force (DMTF) took it upon itself to create just such a VM format and call it Open Virtualisation Format. The organisation even went so far as to release, back in January, version 2.0 (PDF) of the spec.
VMware's Lawrence Lamers chairs the working group that cooked up OVF and the virty giant offers a tool to handle the files. So does Microsoft Neither has placed OVF front and centre in their virtual control freaks.
The format is nonetheless popular with some virtualisation aficionados, such as Alastair Cooke, creator of popular VMware testing tool Autolab, who thinks “a standardised way to transport one or more VMs between different virtualisation platform instances is a great thing.”
Cooke uses OVF “to distribute the AutoLab for use on vSphere” and says it is “the wrapper to put around a VM or group of VMs when they are moved between private and public clouds, a foundation of cloud mobility which should be an important consideration for public cloud customers.”
He therefore likes OVF 2.0 because it “brings a lot more of the VM metadata along, which will be helpful for moving VMs around and having them work correctly after the move.”
“I’d love to see this move to the point here the VM was not tied to a particular virtualisation platform but that’s a long way away,” he told The Reg by email.
Gartner analyst Michael Warrilow also likes OVF, and says “Version 2 is definitely an improvement,” thanks to enhanced cryptography and ability to place VMs in different locations.
But he also says nobody uses the standard.
“Gartner sees virtually no interest from enterprises,” he told The Reg. “The only place it has had some value is it makes evaluating software easier.” While the analyst outfit recommends its clients specify compatibility with the standard when issuing requests for proposals, the fact the likes of Amazon Web Services don't include the standard in their cloud services makes it a nice idea in theory, but possible to ignore in practice.
Warrilow says this “varying level of support from vendors” is the reason for the standard's woes, but doesn't see that changing even though he feels a common virtual machine format is useful.
Cooke has a theory about why the industry may be cool on the concept: VMware chairs the OVF committee.
“I wonder whether VMware’s role as the developer of the OVF standard is preventing competitors making a lot of use of OVF, even though the standard is owned by the DMTF,” he wrote.
Warrilow's theory on OVF apathy lays the blame at the feet of the standards process, which he says generally moves at such glacial pace that its emissions are often irrelevant by the time they arrive. That may be the case for OVF, but Warrilow also mentioned the joke du jour about public clouds, which draws its inspiration from Hotel California: you can check out any time you want, but you can never leave. ®