Stephen O’Grady of RedMonk has written an extended discourse on virtual appliances and the importance of the operating system to ISVs. Now I’m not an analyst, and I can’t predict the future. I do know that our initial partners in the Virtual Appliance Marketplace (mostly hardware appliance vendors) say there is demand among their customer base, and it’s easier for the vendor to control the quality of the product. It seems like a real advance in software distribution models. I think the uncertainty I’ve seen among some industry observers comes down to this: the customer makes an explicit agreement with a hardware appliance vendor to provide security updates to the OS and application, since the colored pizza box is closed. Do we trust application vendors to deliver the same level of security updates?
My conclusion, based on the above? If support matters, operating systems matter. If the subject is production systems, then, operating systems matter.
What’s equally clear, however, is that VMWare’s contention, made
here at VMWorld, that the role of the operating system is changing is
accurate. This is reflected not only in the technical innovation seen
around virtualization from both a hardware and software perspective,
but by the complexity of the support questions facing ISVs.
Unfortunately this convenience does not come without a cost. As
described in several of the sessions at VMWorld, the very notion of a
virtual appliance blurs heavily the line between application and
operating system. VMWare was, to a person, very up front about the more
limited role that operating systems play in the virtual appliance
world. Their contention is simple: general purpose operating systems
are designed to handle a number of tasks, but only some of these are
applicable in the context of a virtualized environment. Why bother
including the hardware support in your operating system layer, they
ask, if the application is being deployed to a virtualized environment?
They propose instead that application vendors create and deliver as
part of their appliance operating system layers that include only what
From an engineering perspective, this has an undeniable appeal: it’s
simplicity taken to a whole new level. What I’m wondering about is how
this will work in practice.
We’ve already cited another part of this post a few days ago, but here’s Jonathan Eunice of Illuminata on virtual appliances:
No doubt appliances have been oversold at times—never more so than
during the first Internet boom when some envisioned that hardware
appliances would replace general purpose servers for running everything
from databases to email. (Subscribers, see our The End of Cobalt and
the Appliance Era That Never Was.) And, even with infinitely “softer”
and more transportable virtual appliances, the fundamental appliance
concept implicitly assumes that appliance images don’t have to
routinely be modified, patched, or tweaked, in which case the “just
fire it up in a virtual machine” promise starts to ring a bit hollow.
Still, some types of applications (such as firewalls and web servers)
can indeed be quite standard—at least within a given enterprise—and
others have such truly ugly dependency sets that anything providing at
least some simplification is welcome. (We very much like Trac as a
project tracking system, but oh the installation process!) Thus, we
don’t view virtual appliances as the right answer for every software
deployment migraine, but they can soothe headaches for all that.