(This is Part 1 of a ‘Real-Life VDI’ mini-series – see also Part 2 “High-End Graphics”, Part 3 “Cost”, Part 4 “Recent Announcements” and Part 5 “Future of VDI”)
In this mini-series I’ll share my real-life experience based on some of my recent VDI client engagements. So it’s a reflection of what customers actually implement (and struggle with) all mixed with my comments, evaluation and opinion. In particular I’ll talk about the following aspects:
– Software Stack – or – “Is there a common software stack for VDI in the industry today?”
(Is it Citrix, VMware, Microsoft or another vendor’s stack?)
– Advanced Graphics – or – “I need advanced graphics, what shall I do, is it always out of scope?”
(Looking for an “at a glance” view of advanced graphics capability by vendor …? Then read on …)
– Cost – or – “I can’t get to a viable price point for my VDI environment, what am I doing wrong?”
– Future/Vision – or – “Is VDI for me? How will recent announcements impact the future of VDI?”
While I’ve been involved with desktop virtualization for several years, this article was triggered by the emergence of “patterns” in my VDI projects over the last year (based on field experience, not some nebulous industry projections).
These patterns are currently common across customer from various vertical backgrounds – although a large segment of my recent engagements has been with European system integrators and customers in the financial sector, typically of larger size with targeted environments of 2k seats up to 100k seats. That also means that some of these implementations were deployed as private desktop clouds and Desktop as a Service (DaaS) environments
Most of those already had an existing POC, pilot or smaller production environment in place and consider moving to “their phase 2″. Phase 2 typically involves a larger production user base (> 500 seats), often aiming to include more demanding user categories (power users and higher graphics requirements) and distributed environments (i.e. branch offices).
This article will be mainly restricted to VDI (HVD “hosted virtual desktops” based architectures). However, I hope we all agree we’d be pretty poor architects/consultants if HVD was our only answer to every desktop infrastructure scenario, but please allow me to leave it at that …)
… I hope we all agree that we’d be pretty poor architects/consultants if HVD was our only answer to every desktop infrastructure scenario …
I started to write this article just before making my way over to VMworld Vegas and some of the announcements and discussion (including a particular enlightening one with Massimo Re Ferre from it20.info ) changed some of the dynamics in this space so I’ve added “Rethinking my opinion of VMware’s End User Computing capability and vision“.
But let me first share my thoughts as originally intended – that will also make the significance of the recent announcements clearer.
Let’s start with the software pattern … is there really something like a “typical” stack for VDI components …?
Pattern 1: The Status Quo of VDI Software stack: VMware or Citrix?
OK, I admit, this can be seen as a dubious title. Is there really a status quo (and can there realistically be one), why restricting it to VDI and what about the other players in the game …?
And that’s exactly the point, it’s currently not a clear-cut single vendor stack we see typically being implemented.
So the question I typically get is “Am I the only one with this odd software stack, there are just too many combinations of products from different vendors – what are others (in my industry) using…?”
“Am I the only one with this odd software stack …?”
The majority of customers asking me this question actually then go on to describe a very similar (multi-vendor) stack …
The majority of customers asking me this question actually then went on to describe a very similar (multi-vendor) stack – including the last 3 large customers in a row over the last couple of months … and that stack was:
L1 (Hypervisor and hypervisor management): VMware vSphere
L2 (Broker/Session Management): Citrix XenDesktop
L3 (“Application Virtualization”): Microsoft App-V
L4 (Profile Management): roaming profiles/folder redirection and/or pilot to implement AppSense
As you can imagine, I am simplifying the layers in the interest of time and again, I am not making any claims that this is an objective representation of all customer segments, sizes and regions by any means. (I will cover other solution like Virtual Bridges’ Verde – which I’ve recently worked with – in a future post).
Affinity typically decreases with the higher layers so for instance App-Virtualization and Profile Management are less likely to be nailed down. Also, before I attract the wrath of VMware View fans, I am not making a general stack recommendation here, The purpose of this article is to convey what customers decided to implement after careful consideration.
(also please check out “rethinking my view of VMware’s end-user capability“)
Hypervisor of choice for VDI: ESXA pretty obvious choice you might say… arguably the most mature, feature-rich hypervisor in the market.
In reality this is often an evolution of what the client did for server virtualization (rather than based on specific evaluation of suitability for VDI) … existing skill set, license agreements, confidence and relationships often make this the natural choice… .
Many clients confirmed that they are actively evaluating hypervisor alternatives for VDI attempting to reduce cost
Most however confirmed that they are actively evaluating alternative hypervisors attempting to reduce cost (with e.g. XenServer but actually increasingly Hyper-V), with one large customer actually stating that the directive given by their management is Hyper-V “whether they liked it or not” due to existing licensing agreements with MS.
The SP1 addition of Dynamic Memory helped and RemoteFX has the potential to address some of the graphics requirements, however missing NAS support (except CIFS) for Hyper-V and the upcoming release of SCVMM 2012/Windows 8 (which many see as first credible competitor to vSphere) seems to be holding actual adoption of Hyper-V as platform for VDI back …
Comment: MS just announced that full NAS support will be part of Hyper-V3 (Windows Server 8).
XenServer is considered when a single (Citrix) vendor stack is preferred (support, integration, skill set) and features like IntelliCache and GPU pass-through are hypervisor specific considerations customers take seriously (like RemoteFX for Hyper-V).
Broker of Choice: XenDesktop
There is a multitude of “connection broker” technologies in the market (Quest vWorkspace, Leostream, Virtual Bridges Verde etc.) with varying capabilities and scope (session management, deployment etc.). There were endless discussions and many points raised but when asking the clients “what’s the main reason for picking XenDesktop” the common points were:
– multi-hypervisor support – “If we decide to switch hypervisors to XenDesktop or hyper-v we can keep XenDesktop in place.”
– HDX protocol advantages – mainly bandwidth efficiency and high-end graphics (3D) capabilities over PCoIP and RDP (comment: see “Section for high-end graphics” and “changed view” for updates on VMware capabilities)
– Citrix Portfolio – this is a little more difficult to quantify but it became clear from the discussions that many customers appreciate the breadth and heritage of Citrix’s end-user capability.
The “Flexcast” concept Citrix promotes and the technologies it provides to enable this “one does NOT fit all” approach resonates well with clients.
The fact that they can not only get VDI and streamed applications but also hosted shared desktopss (aka presentation server/terminal server/XenApp) from the same vendor alongside various network appliances for delivery optimization seems to play an important role alongside the fact that Citrix receiver promises connectivity from “any” device.
The overall value proposition of these capabilities made XenDesktop the product of choice.
OK, so what about Application Virtualization and User Profile Management …?
Application Virtualization: Microsoft App-V
Let’s not get into a definition of app virtualization (as there are different models) but here I am referring to the ability to sequence an application, deliver it to the end-point (e.g. stream it to a virtual desktop) and have it run in an encapsulated runtime environment “bubble” with the usual advantages of portability and isolation.
Many vendors provide solutions in that space (VMware with ThinApp, Citrix – XenApp, Symantec SWS and others).
From my experience app virtualization in “phase 1” is often not fully explored. One of the biggest drivers for app virtualization is the goal to deliver stateless desktops but reality prevents in many cases the use of 100% stateless instances in larger environments, whether for technical reasons (e.g. typically not all apps can be virtualised) or organisational (user insisting on locally installed apps). However, some administrators I worked with even started to virtualize and stream apps to physical endpoints before looking to virtualize the desktop itself..
Technologically ThinApp has the advantage that it runs in “user-mode” which in simple terms means that the app is less likely to affect other processes in case of failures, it is also using an agent-less approach – generally favoured to avoid yet another update and certification point. But at the same time it is this agentless model which makes it less integrated into the central management environment.
Administrators were pretty consistently telling me that the level of integration and central management of application virtualization makes them pick one solution over another
Administrators were pretty consistently telling me that it is this integration and central management which makes them pick one solution over another (on a very practical level) and currently favour App-V over ThinApp even though some improvements have been made with basic integration in recent View releases.
While XenApp is clearly used in many accounts for Server Based Computing (aka terminal services) I have seen only relatively limited use for app streaming in multi-vendor “best of bread” environments.
Because of the emerging nature of app virtualization however the affinity to a product/vendor in accounts is here less strong than e.g. with the hypervisor or broker – often still more a vision than final choice in “phase 1”, while in “phase 2” it is typically recognized as a required enabler for (cost) efficient VDI environments using stateless images.
Ruben Spruijt from PQR has created a whitepaper Application Virtualization Smackdown covering this topic in great detail – definitely worth a read if you are exploring this area.
Profile Management: Windows Roaming Profiles, AppSense
Arguably the least defined and therefore potentially most complex aspect of desktop virtualization (not just for HVD) is the profile management.
Least defined because products have evolved from initially addressing the “user profile” issues to include an ever increasing scope of “user environment management” (UEM).
User Environment Management is undoubtedly the component virtualization architects who have grown from server virtualization into desktop virtualization typically struggle with most.
It’s also undoubtedly the component virtualization architects who have grown from server virtualization into desktop virtualization (like me) typically struggle with most. When I first worked with AppSense years ago I was dazzled by the capability but also repelled by the complexity of user management in general – something desktop admins have no issues with.
In simplified terms UEM goal is to achieve a consistent user experience across images and devices, reduce login times and address consistency issues with classic Windows user profiles. However, products like AppSense or RES provide capabilities far beyond that by including aspects of resource, security, license management and reporting capabilities.
Out of the last 4 larger engagements, 3 initially used Windows roaming user profiles and were at varying stages of piloting AppSense (one also considered RES). One client stated that they were not going to investigate/use another approach anytime soon (stayed with roaming profiles and folder redirection).
In my view there is no easy answer or recommendation without deeper analysis and a generalisation is dangerous, so let me be clear – while there is no doubt that you will need to address the issue of user environment “mobility”, it is a very individual technology decision which will require you to invest in piloting the approaches and determine what scope you want it to address.
OK, that was the software stack … so what about the Achilles’ heel of HVD … High-End Graphics …? What is really achievable with today’s technology? See Part 2 “High-End Graphics” …
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