SD Times recently published an interesting article about “cloud interoperability”. It has some well-informed opinions. But, like all Cloud-related discussions, it also suffers from mixing a bunch of things. The word “interoperability” is alternatively applied to the Cloud infrastructure services (in which case this “interoperability” is a way to provide application “portability”) and to the Cloud-hosted applications themselves.
Application-level interoperability (“look, my GAE-hosted app successfully sent an HTTP request to an Azure-hosted app, open the champagne”) is not very new or exciting anymore and is often used as an interoperability smokescreen (hello Salesforce.com). Many of these interop concerns are long solved and the others (like authentication and data migration) need to be solved in ways that don’t care whether the application is hosted in your Silicon Valley garage or near the Columbia river.
Cloud infrastructure compatibility (in other words application portability) is the more interesting discussion. I keep reading that it is needed (“no vendor lock-in, not ever again”) for enterprises to move to the Cloud. Being a natural-born cynic, I always ask myself whether those asking for it are naive (sometimes) or have ulterior motives (e.g. trying to catch-up with Amazon by entangling them in the standards net – some of my fellow cynics see the Open Cloud Manifesto as just this).
Because the reality is that, Manifesto or no Manifesto, you are not going to get application portability across IaaS-type Cloud providers. At least for production applications. Sorry. As a consolation prize, you may get some runtime portability such that we’ll be shown nice demos of prototype apps moving from one provider to another (either as applications or as virtual machines). Clap clap until you realize that they left behind their monitoring capabilities, or that their configuration rules don’t validate anything anymore. And that your printer ran out of red ink when printing the latest compliance report. Oops.
Maybe I am biased because they are both my friends and ex-colleagues, but the HP guys make the most sense in the SD Times article. Tim Hall has it right when he suggests “that the industry should focus on specific problems that it is going to solve around deployment and standardized monitoring”. And the other HP Tim, Mr. van Ash, rightly points out that we should “stop promising miracles”, which Forrester’s Jeffrey Hammond echoes, saying that there is a difference between a standard and “plug-and-play in reality”.
Tim Hall uses SQL as an example of a realistic common baseline. J2EE would be another one. They provide a good reality check. Standards are always supposed to prevent vendor lock-in. And there is a need for some of that, of course. But look at the track records. How many applications do you know that are certified and supported on any SQL database, any Unix operating system and any J2EE app server? And yet, standardizing queries on relational data and standardizing an enterprise-class runtime environment for one programming language are pretty constrained scopes in the grand scheme of things. At least compared to all the aspects that you need to standardize to provide real Cloud portability (security, monitoring, provisioning, configuration, language runtime and/or OS, data storage/retrieval, network configuration, integration with local apps, metering/billing, etc). And we’re supposed to put together a nice bundle of standards that will guarantee drag-and-drop portability across all these concerns? In how many lifetimes? By then, Cloud computing will have been replaced by the next big thing (galaxycomputing.com is still available BTW).
Not to mention that this standardization comes hand in hand with constraints on what you can do. That’s why I read Amazon’s Adam Selipsky’s comment that allowing customers to do “whatever they want” is vital as a way to say “get real” to requests for application portability, while allowing him to sound helpful rather than obstructionist.
This doesn’t mean that these standards are not useful. They make application portability possible if not free. They make for much improved productivity through generic tools and reusable developer knowledge. We still need all this.
Here is the best that can realistically happen in the “application portability across IaaS providers” area for at least 10 years:
- a set of partial standards for small parts of the Cloud computing domain (see list above), many of which already exist.
- a set of RightScale-like tools that do a lot of the grunt work of mapping/hiding/transforming between providers, with various degrees of success.
- the need for application providers to certify their applications on Cloud providers one by one anyway and to provide cloning/migration as a feature of the application rather than an infrastructure-level task.
That’s assuming that IaaS providers become a major business, that there remains a difference between service providers and software providers. The other option is that the whole Cloud excitment goes back to SaaS only, that application creators are also hosting providers, that the only resource you get in a “utility” fashion is the application itself. At which point application portability is not a concern anymore and we go back to “only” worrying about data portability and application interoperability, an easier problem and one on which we have come a long way already. If this is what comes to pass then the challenge of Cloud portability may well be one of the main reasons. Along with the lack of revenue/margin potential for many of the actors in an IaaS world, as my CEO is fond of pointing out.
[UPDATED 2009/4/22: F5’s Lori MacVittie provides a very nice illustration of the same point, in her explanation of why OVF is not a cloud portability silver bullet.]
[UPDATED 2009/6/1: Soon after posting this entry I was contacted by people at SD Times about turning it into a “guest view” article in the June issue. It has just been published. It’s also in the paper version.]