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App Virtualization: Why We Need Better Options

Golden disk images are simple, but they won't cut it as implementations get more complex. Here's the problem and what vendors are doing about it.

Application Bundling

The key strategic decision when determining how to deploy and administer virtualized applications is the mode of packaging and distribution. The default--ever since VMware, the market-share leader in virtualization software, adopted the format--is disk images. Now known as virtual appliances, images are bundles comprising an operating system, applications, and configuration details that completely describe a VM's runtime environment.

While this approach, which is borrowed from deployment practices pioneered by enterprise PC client distribution, is simplistic, the benefit is that it's repeatable: Each new virtual application is identical to the golden master. IT likes repeatability, with good reason.

Unfortunately, problems arise once the pristine image is subjected to the vagaries of operating system patches, application updates, and configuration changes. Applications, once released into the runtime wild, tend to quickly diverge from the golden image.

There are a couple of ways to address this problem. One is a reprise of the Unix diff patch management approach, in which the current state of an application or system is compared against a prior snapshot. Much like image-based disk backup software, this technique can identify changes at the disk-block layer to create a delta image that can transform applications from one golden image to another.

This approach can be problematic, however. "If you can make an application totally stateless, then it works," says Shawn Edmondson, VP of product strategy at private cloud software provider rPath. But that's not possible for most applications. For deployed applications accumulating state information such as configuration settings or user information, IT ends up creating separate diff images for each VM instance. "Most people use golden images for new deployments but do updates the old-fashioned way," he says. Read: patch files and binary package distributions applied on each VM--which clearly isn't scalable.

Another, more flexible strategy entails using templates, which may include, for example, scripts to pull Perl packages from CPAN or build a standard J2EE stack. This tactic allows the same application model to be used on different cloud environments, both private and public. Such a template-driven approach facilitates updating stacks without rebuilding the entire bundled disk image. Nand Mulchandani, CEO and co-founder of cloud management system vendor ScaleXtreme, describes this approach as "dynamic VM assembly."

This strategy extends traditional software-building approaches, like makefiles and package managers, which focus on source code and application libraries, into the realm of VMs and virtual appliances. Developers build a detailed model of all the application and OS binary files, reminiscent of source code makefiles or Linux binary packages. It's no coincidence that rPath is a leading advocate of this approach since the startup was co-founded by an originator of the Red Hat Package Manager.

However, Mulchandani cautions against commingling application and operating system configurations if you plan on deploying to public clouds, since even IaaS providers using the same Linux distribution--say Red Hat or Centos--often use different kernel or library versions in their VMs. That's a critical detail that IT can't control. He also points out that application models can get quite detailed and that building them is painstaking, time-consuming work that can be impractical for large companies with scores of applications and thousands of machines.

So what's the answer? For now, that has a lot to do with whether you're using a public or a private cloud. Yes, SaaS products like ScaleXtreme's are trying to bridge that gap, but they are very new and are designed to do everything from their own service--so they don't integrate well, if at all, with existing internal management software.

What percentage of your company's production servers do you expect to have virtualized by the end of next year?

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martinpdx2
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martinpdx2,
User Rank: Apprentice
11/9/2011 | 5:58:51 PM
re: App Virtualization: Why We Need Better Options
Great article around the complications enterprises face as IT environments become even more complicated G㢠the change agents here being virtualization and the Cloud. Changing the desktop model to a virtualized and separated set of resources (O/S, apps, and user data & settings) provides the benefit of independently managing each layer and applying it as needed across many technologies. Organizations want Windows 7, virtual desktops, and session-based solutions, but they often lack the knowledge to transform their application portfolio into solutions that meet the needs of a constantly changing IT landscape.

This is where application virtualization becomes a building block for desktop transformation. Applications are the essential resource that each user needs to be productive. The problem for organizations is how to take hundreds or even thousands of applications in various formats and create packages that can be delivered to traditional desktops or desktop virtualization technologies like VDI and session-based that support thin clients, tablets, smartphones, non-managed and non-Windows devices. CIOs are realizing that the previously manual process of testing applications, upgrades, patches and fixes, for compatibility, and then packaging them for the myriad environments in which they will operate G㢠is an IT black hole.

So the question becomes G㢠how can enterprises Gă future-proofGăÍ their IT environments with strategy and best practices that embrace disruptive technologies? This is where Application Readiness has taken center stage, as automated tools are now essential to ensure that the application estate is future-proofed, and that key applications are up-to-date and in the hands of business users, when and where they need them.

Flexera Software recommends the following 6 step strategy for Application Readiness to ensure enterprises applications can be easily deployed and maintained in all environments G㢠including virtualized and Cloud-based environments:
(1) - Identify - getting an accurate view of the applications currently deployed to ascertain effort required for deployment, and identifying any not being used

(2) Rationalize G㢠determine which applications are actually needed from the application inventory

(3) Assess compatibility G㢠applications still require compatibility testing prior to virtualization

(4) Plan G㢠many organizations lack adequate information when planning and budgeting for projects, having an accurate view of the applications targeted for migration and their readiness for application dependent projects provides data for budget and resource allocation

(5) Fix and package G㢠applications which presented issues during the assess compatibility stage must be fixed or replaced

(6) Deploy G㢠with an automated approach, the resultant packages are automatically added into the electronic software distribution (ESD) solution without copying of files and manual hands off.

As Kurt Marko points out in his article, application environments are more complex than ever. And it is no longer practical to implement Application Readiness best practices manually. Implementing Application Readiness solutions to automate the most time-intensive and complicated aspects of the process is essential.
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