Solaris: the awesomest virtualization ever?

There's an advocacy piece, in Forbes of all places, that offers a pretty unbalanced perspective on Solaris. (I hesitate to even link to it, because it feels like sensationalism just to generate huge numbers of outraged readers.) The author, Dan Woods, doesn't mention any negative points to Solaris at all, which should raise the suspicions of any reader with critical thinking skills, but I wanted to debunk some of the virtualization statements in particular:

Dan claims that Linux virtualization is the result of un-coordinated development from a number of companies, and Solaris virtualization is better because it's engineered "top to bottom" at a single company. Seamless integration can certainly offer advantages (see Apple), but I take issue with both his observations about the ecosystem and the conclusions he draws from them.

Aside from containers, Solaris uses hypervisors from Xen (marketed as xVM), and VirtualBox (from the innotek acquisition). Neither of those solutions were designed for Solaris; they were adopted years later to fill gaps in Sun's offerings. However, they are currently developed by Sun, so you still have the "single company" argument. About that...

Where I come from, being completely dependent on a single company is a bad thing, and I'm not even talking about the freedom of open source. It's called "vendor lock-in," and it's bad because there's no competition and customers are at the mercy of that single company's roadmap. Companies invest lots of money developing and supporting 3rd party ecosystems because it's a critically important to their customers. Anyways, looking at it from another angle, isn't it disturbing that virtualization ISVs don't consider Solaris important enough to target? Sun had to buy them outright or develop solutions in-house.

Dan claims Solaris containers cause a 2% performance degradation, vs. "about 20% for a hypervisor." While it's true that Forbes isn't a good forum for presenting performance analyses, without even a hint about where they came from, offering these numbers is ridiculous. It's often true that you can pick a specific benchmark and environment to support any argument, but Dan didn't even pretend.

Finally, I thought Dan's most interesting claim was the one for which he didn't offer any supporting arguments at all: that Solaris is now safe. Even if he's right, and Solaris is indeed the most awesome OS ever seen, that still doesn't guarantee it a slot on the Oracle roadmap.

Oracle buys another hypervisor?!

Oracle made headlines for two acqusitions in the past month, Sun and Virtual Iron. By my count, that makes them the proud owners of no fewer than four x86 hypervisors: Oracle VM, Sun's xVM Server, Sun's xVM Desktop (a.k.a. VirtualBox), and Virtual Iron. (I've never really understood why Sun had two.) All but VirtualBox are based on Xen.

Even with this surprising success in the game of "collect the Xen implementations," that still leaves at least Red Hat, Novell, and of course Citrix itself offering competing Xen solutions. I'll admit the Unix wars predate me, but that seems like an impressive degree of fragmentation. Still, Red Hat has announced plans to abandon Xen for KVM, and even Novell included KVM as a tech preview in SLES11. There's no question that the number of Xen-based products is about to significantly shrink.

I've even seen one person speculate that the cost of maintaining Xen is so high, that with Red Hat pulling out, Oracle must have been worried about strengthening their Xen development capabilities.

What's worse though is that each of those Oracle hypervisors has its own management stack. Systems management is one of those areas that sounds really easy, but in practice never is. Management software contains so many layers that it's hard to find anybody who actually understands the end-to-end details of a particular code path. You need translation layers for components that are too old, too new, or fit at a different layer, or written for a different management stack. In this case, you might find one management stack built on xm, another built on libvirt, another built on CIM (and "enterprise frameworks" are a whole other world of complexity). Do they use OVF for image files? Should they? Every design question has tradeoffs and requires serious consideration.

Speaking from experience at a large company, I expect there will be at least 6 months of churn while architects furiously scribe presentations, rearrange block diagrams, create hypothetical development sizings, establish migration plans for legacy customers, escalate issues to management (which will be sorting itself out too), find and get input from related organizations ("how does this affect our relationship with VMware?"), and in general figure out what they're doing. After all the dust has settled, they'll still need to write the code.

Will the eventual result of this consolidation be a stronger Xen ecosystem a few years from now? To be honest, I couldn't care less... but it could be worth the cost of a bag of popcorn.