Service-oriented architecture (SOA) and virtualization seem made for each other, but management, both the software kind and the human kind needs to improve before the coupling can reach its full potential.
Virtualization offers the ability to not only ensure service availability and scalability, which is often touted as its main selling point for SOA, but also provides the ability to quickly update and change services without disrupting applications, says John Michelsen, chief architect at testing vendor iTKO Inc. While he said he is actively recommending virtualization to his customers doing SOA, he offers the one caveat that lack of effective virtualization management software and skills make it hard to track and find services running on numbers of virtual machines in an enterprise environment.
"If you were an enterprise IT guy and you decide that your production hardware is going to go virtual," Michelsen said, "I believe there's way more upside than downside. But the one downside is it will get messy. You'll have tons of virtual machines sitting on large storage arrays and you could end up in a bit of a management nightmare.
The problem is similar to the rogue Web services that can plague an enterprise SOA implementation if governance with a registry/repository is not in place. Michelson said that at the moment there is nothing like UDDI or a registry/repository that can catalog virtual machines.
"The larger and more complex the SOA gets," he said, "the more you're going to get value from the fact you've virtualized. But there is a management aspect to it and it's something I don't think is solved. The existing virtualize platforms out there aren't very good at it. We need almost a cataloging system and I haven't seen anything like that. We do it with a wiki page. We maintain wiki's on all the virtual machines we've created, where they are on the network drive, but I haven't seen a good cataloging system for virtual machines."
Andrew Hillier, the co-founder and CTO of CiRBA Inc., a data center intelligence vendor, also sees a bright future for SOA coupled with virtualization and said he believes help is on the way.
"The whole virtualization segment is going through maturation to become that truly reliable technology," he said. "But I think it's getting there very, very quickly."
Yett it will not be entirely a software fix, Hillier said. IT professionals working on virtualization will need to bridge a gap between those who view it from a hardware perspective and those who are looking at it for SOA.
Having recently attended a conference on SOA and virtualization, Hillier said he observed two camps forming around the technologies.
"There were a group of people who were looking at SOA and they were looking at Ajax technologies," he said. "Then there were a group of people focused on virtualization and they were looking at their current environment."
Hillier suggested that the cutting edge SOA group and the traditional IT management group need to converge to both virtualization and SOA to reach their full potential.
Andi Mann, an analyst covering virtualization for Enterprise Management Associates, said he sees a lack of communication between the people who manage hardware virtualization and the people who are looking at SOA virtualization.
"Ultimately," Mann said, "that is going to be an unsustainable model."
Noting that virtual machines have been around for 40 years in the mainframe world where the management issues were long ago worked out, Mann said the problems exist mainly with management of the x86 servers popular in the Web services and SOA world.
"In the x86 market specifically the management tools are not comprehensive," Mann said. The management problem described by Michelsen, which Mann calls "virtual server sprawl," is being focused on by niche vendors, as well as both major IT management vendors and provisioning vendors. The focus is on tools to handle virtual environments, but all the pieces of the puzzle are not in place yet.
"The problem of management is two-fold," Mann said. "First, management of virtual systems themselves is not comprehensive so far. There are big gaps in the capabilities for managing these virtual systems. The second problem is that even now management of virtual systems tends to be separated from management of physical systems. That causes all sorts of problems such as the virtualization team not talking to the server management team and ending up with conflicting resource requirements."
Like Michelsen and Hillier, Mann said he believes these issues, which might hamper the advance of SOA and virtualization, can be worked out. "Ideally," he said, "we need to get to a situation where we are managing virtual and physical systems seamlessly.