Mission Creep: Open Source Virtualization Usage Models Proliferate

July 31, 2007

by Emerging Technologies Team

Over the past few years, a lot of IT hype has been expended on virtualization technology. It was ready for prime time, or it wasn’t; everybody was using it already, or they weren’t; it was expensive, or it wasn’t; and so on. Now that Red Hat Enterprise Linux 5 has been available for a few months, we are starting to see how customers are actually going to use virtualization. This allows us to get to the truth behind the hype.

A brief summary

  • Customers are quickly realizing that Red Hat Enterprise Linux virtualization, which is provided as part of the base product for no additional cost, works really well. It’s stable, mature and easy-to-mange.
  • Para-virtualization, available for Red Hat Enterprise Linux 4 & 5 guests, delivers performance that is close to bare-metal. So why not use it everywhere?
  • Full-virtualization performance is dependent on the application – so it needs to be deployed with some care. But, enhancements due at the end of the year will close the gap with para-virtualization significantly. This will make Red Hat Enterprise Linux a terrific virtualization platform for any Windows system, with better storage virtualization and driver support than is available with proprietary virtualization products, at much lower cost.
  • Consolidation frees up systems that can be redeployed as fresh Red Hat Enterprise Linux servers to handle rapidly growing IT requirements.
  • The exciting uses of virtualization lie beyond consolidation – they are in areas of high availability, operational flexibility, resource management and enhanced development environment.
  • Red Hat Enterprise Linux Advanced Platform, with its comprehensive storage virtualization capabilities, can save you from having to purchase lots of other expensive software.
  • Live migration, which is also included in the base product, is the key to flexibility.

Customers are deploying today. For example, take a look at Comcast, a recent Red Hat Innovation Award winner.

Partners are starting to create appliance-based solutions based on Red Hat Enterprise Linux virtual guest servers. For example, take a look at this.

Details

For those of you with a little more time to spare, let’s take a closer look at what we are starting to see.

First off, it’s clear that people are really impressed with the performance and simplicity of para-virtualization. It seems that this is going to drive adoption of virtualization more pervasively and earlier than we anticipated. Basically, there is no reason to not run para-virtualized while the additional flexibility it offers makes it a no-brainer. For any Red Hat Enterprise Linux 4 or 5 application, para-virtualization will soon be the default deployment.

Next, the performance of full virtualization, which is needed for Red Hat Enterprise Linux 3 and third-party operating systems, varies with the application and i/o environment, so needs to be checked for every deployment. Meanwhile, with the aggressive development underway on full virtualization enhancements that are due to be delivered in version 5.1, performance will increase significantly.

Essentially, it’s clear that virtualization is becoming a fundamental requirement for any IT deployment. Discussions about whether the technology is best in the operating system, or in a separate software layer, or in the processor silicon, are still raging, but under any circumstances it is becoming a commodity. Red Hat’s entire business has prospered on its ability to commoditize software technologies, so we strongly believe that by building virtualization capabilities into the operating system, the open source model will deliver best-of-breed solutions to customers faster than any other.

We are also seeing acceptance of the virtualization infrastructure capabilities that we created, such as control libraries (libvirt) and management tools (virt-manager). Libvirt provides a much-needed level of isolation between management applications and the underlying virtualization technology. Isolation that will enable us to quickly adopt other virtualization technologies, for example projects such as KVM or Intel/AMD processor enhancements, without impacting higher level applications.

What is also clear is that once customers start using virtualization, they immediately find uses for it that were not originally considered. One reason for this is that virtualization is provided in Red Hat Enterprise Linux 5 for no additional cost – so it can be put to a wide range of uses, on any server, immediately. On the other hand, competing proprietary products can be expensive so they may not be cost-effective for many of the potential usage models.

The usage model that is best understood is consolidation – moving the load from several physical servers onto a single server. This has been very popular in the proprietary virtualization market, mostly because a high consolidation ratio is necessary to justify the purchase of the virtualization product. Also, many customers have large numbers of lightly loaded Windows servers, so consolidation makes a lot of sense. As the performance of Red Hat Enterprise Linux full virtualization increases, we expect to make great inroads into this market.

Meanwhile, consolidation ratios for Linux systems are proving to be lower than Windows because Linux servers tend to be more heavily loaded. Interestingly, the freed-up servers are being redeployed as new Red Hat Enterprise Linux systems, running new workloads. Customers have mentioned that their IT departments have no difficulty putting the systems to good use.

One classic downside of consolidation is that it is possible to end up with “too many eggs in one basket,” if the consolidated server fails it takes down all the virtual machines. So every deployment has a trade-off to make: efficiency against risk. Minimizing the risk takes several dimensions, starting with using good-quality hardware that is properly cooled. On the software side, Red Hat has extensive experience in delivering solutions that provide high levels of reliability, availability, etc. in a secured fashion. And products such as Red Hat Network and Red Hat Command Center simplify large-scale management. In fact, as virtualization technology commoditizes, it is in the management arena that competing solutions will differentiate themselves.

Improved resource management is rapidly emerging as a major benefit of virtualization. It is possible to add and remove CPUs and memory from a running virtual machine so that the performance of the system can be tuned to the load. It is also possible to “live migrate” virtual servers across physical systems while they are active (this feature is limited to para-virtualized guests today but will hopefully be available for fully virtualized guests with 5.1). Live migration, of course, can help improve application availability by enabling virtual servers to be relocated easily during maintenance and reconfigurations. Customers are starting to use these features today with their Red Hat Enterprise Linux virtual guests.

A rapidly growing number of customers and partners are realizing that virtualization allows them to create complete virtual appliances, with the operating system and application provided as a fully integrated solution, with the specific configuration, tuning and security environment baked in. Using Red Hat Enterprise Linux as the virtualization foundation, it becomes possible to deploy an appliance based on any operating system. Early adopters are doing this today to deploy older and stable application stacks on new hardware, avoiding the need to perform an operating system upgrade.

Application developers have been quick to realize that virtualization allows them to rapidly create multiple build and test environments on a single server – or their own desktop. This greatly improves their productivity and is useful in both Linux and Windows development shops.

So, as you can see, the range of uses of virtualization is growing rapidly. Adoption of a solid virtualization environment, such as Red Hat Enterprise Linux, will become pervasive, regardless of the end-user operating system. The success of proprietary virtualization products over the past few years clearly shows how much customers value them. With Red Hat Enterprise Linux 5 providing a highly competitive open source solution adoption of this technology, it will continue to grow dramatically.

To learn more about Red Hat and virtualization, see here.

To see what else the Red Hat Emerging Technologies Team is working on, check here.

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