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July 26, 2011 / Simon Crosby

Beyond the Hype… More Hype (Part 1 of 2)

There’s an infrastructure storm brewing that, when it finally unleashes its fury, will catch off guard every enterprise CIO steadily making progress towards their Private Cloud.  The argument: It’s time to get over our love of Hype(rvisors) and question the value of virtualization in the cloud.    What kind of cloud?  Oh, All kinds.   And lest you want a nutshell summary:  Here is my thesis: The hypervisor as you know it is useful for hosting legacy IT workloads in private clouds.  But beyond today’s Hypervisors, a profoundly important new building block for the cloud will emerge – an even more powerful kind of Hypervisor.

I: The Schism: IT_Ops vs Dev_Ops

I am always surprised by how few IT organizations developing a cloud strategy understand the difference between the typical Enterprise IT infrastructure versus (say) Amazon Web Services.  In the enterprise, every legacy technology ever built remains in service, coddled by an army of dedicated IT professionals whose challenges grow with each new technology acquisition, merger or strategic initiative.  For these poor folk, x86 server virtualization and its evolution into virtual infrastructure has been a godsend.  Legacy workloads, bundled up as VMs, can be efficiently and dynamically spun up on any server, on demand.  IT gets to be greener, more highly available, and more responsive to business needs.  But most importantly, since most workloads are seriously long in the tooth, it allows IT to take advantage of Moore’s Law – replacing old gear with more efficient, faster, smaller devices without changing software.   Legacy workloads can live forever, happily ensconced and managed in VM bubbles, and sophisticated management frameworks provide insight, control and automation of traditionally manual tasks.

But this so-called IT_Ops flavor of cloud lacks important attributes found in public clouds: You have to buy equipment up front, instead of paying as you go, and it is inelastic because your capacity is fixed. By contrast, the “Cloud in your pocket” (the clouds that run the apps on your smartphone or tablet)  runs on big public IaaS clouds such as AWS. There are no IT folk involved here, and the focus is on providing a set of service interfaces to support app developers who will never encounter an IT person.  These Dev_Ops clouds offer rich toolsets for developing, testing, provisioning and automatically scaling a web-services based app and its storage and networking infrastructure, atop a “pay as you go” business model. Examples include Heroku, Engine Yard (which runs Groupon), PiCloudNode.js, VMware’s CloudFoundry or even Red Hat’s OpenShift. By focusing solely on making the developer’s life simpler, and the use of powerful automation frameworks such as Chef, Puppet or tools such as RightScale, the abstraction (service interfaces) of the cloud can quickly move beyond the concept of a VM instance.  VMs may well be used under the covers (they are by the frameworks listed above) as units of workload that can be elastically provisioned using the basic VM-centric primitives of the cloud, but to the user of the cloud they are hidden.  Welcome to the world of next-gen apps, where VMs are best described in PaaSt tense.

The bottom line: The public cloud is PaaS centric. Though you can certainly spin up VMs if you need to, richer app-centric service interfaces let you forget all about them. As better instrumentation of the PaaS layer becomes available, your need to be involved with VMs will steadily decline (good blog here)  Finally, if you are an enterprise user of VMs in an IaaS cloud, you probably use an OS instance provided by the cloud provider (another value-added service) – once again freeing you from any concern about the hypervisor.

II: Big SaaS Couldn’t Give a Hoot about VMs

The Big SaaS properties – consumer and enterprise focused – have historically been built according to highly app-specific needs.  A few notable exceptions come to mind, such as Netflix, whose journey to using the AWS cloud to host their apps is superbly chronicled in Adrian Cockroft’s blog and on the Netflix tech blog.  But many, including Salesforce and Facebook believe they don’t need a hypervisor in their infrastructures.   The argument is simple (and a bit naive): they operate at a scale where the “server virt” consolidation arguments in favor of running multiple VM instances per server simply don’t make sense.  Saving 50% of a server when you have 100,000 of them is kind-of-meaningless.  But there are a couple of reasons why a hypervisor does make sense in large web shops: First, if the infrastructure hosts multiple apps, multi-tenancy of the hardware infrastructure makes sense.   A good example is Yahoo, which has over 250 web properties sharing about 500,000 servers in 26 data centers world wide, and because they grew so rapidly and applied the naive approach, used to run at a shocking 8% average utilization before opting to build a large virtualized private cloud. The other reason to use a hypervisor (MySpace springs to mind) is provisioning cleanliness: each server runs a single VM (which contains an instance of the app) and the operators can insulate their software from different kinds of hardware by using the hypervisor and its virtual hardware as a clean abstraction layer.  Historically this caused overhead since the hypervisor introduces at the very least an I/O overhead, but with the emergence of SRIOV, or with simple PCI pass-through of devices to a VM or VMs, the performance overhead of the hypervisor is tiny.

As more and more next gen apps (both SaaS and PaaS-hosted) are developed, we will quickly move beyond the era of relevance of the hypervisor.  A powerful abstraction, for sure.   Used liberally – everywhere where the lowest levels of infrastructure require multi-tenancy, dynamic provisioning, optimal packing, manageability and high availability – but unimportant to the users of the cloud. A mere capability in the IaaS stack.   Only in the enterprise, where IT is slowly automating its traditional practices and where the traditional single-server-OS based units of work as VMs remain, will the “big brand” hypervisors command a following.  Why? manual procedures for VM Management, that are vendor specific.  The Enterprise Private Cloud market is growing at about 30% per year,  but IaaS and PaaS clouds, already well beyond the hypervisor-as-service-interface, are growing at break-neck pace of about 70% per year, driven by the staggering growth of mobile apps and our insatiable consumer appetite for services.

III: But Wait! That’s all Wrong!

Yes, it is.  There’s something critically important that I’ve left out, that completely changes the relevance of the hypervisor.  It’s so important that I believe the hypervisor will become ubiquitous.  You wouldn’t dare to have a server or a client without one.  More on that in Part II.


  1. Massimo Re Ferre' / Jul 27 2011 5:45 am

    Sometimes I wonder if innovation is happening faster than what customers can digest and cope with. I kind of agree that, in the longer term, the notion of the VM as an “end-user container” may lose relevance because of what you are saying but the question is how long is that “longer term”. People sometimes tend to position IaaS as a thing of the “PaaSt” but yet I meet organizations that have just started “virtualizing” test/dev workloads.

    It took Windows about 30 years to bring us here… I am wondering if we can fix it in 18 months. I also want to point out that Windows brought us a lot of more great things than those it broke (and that we need to fix). Kudos to MS for what they have done. I do admire what they have done for the people.

    The risk is that discussions like this (which has a lot of meat and interesting content) end up being academic discussions for the 99.99% of the customers out there.

    Well at least you seem to agree that the like of facebook and google are not representative of the “average customer”… it’s a start. 🙂


  2. brummieruss / Jul 30 2011 2:41 pm

    Excellent post. The discussion about IT Pro and Dev Pro is one that is going to shake the industry. Even if cloud is a long haul before it is the mainstream ( not the shadow ) for all organizations large and small, the subtle movement is well underway. Hosting companies outside the Tier 1 and TIer 2 cloud providers are now gearing up and the CTO will want to move his IT Pros off the payroll and keep his Dev Pros as they know hold the key to business success. Of course, the PaaS and SaaS guys hold the really big key as they can also rationalise the Dev Pro position but this will be a slower burn. If I was a IT Pro I would be looking hard at my career and realise that having virtualization skills is maybe not the big deal it was say when everyone was a MCSE or CCIE.


  1. Beyond the Hype.. More Hype (Part 2 of 2) « A Collection of Bromides on Infrastructure

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