Last week, I wrote about how Desktop as a Service is essentially the same technology as VDI -- just hosted and managed by someone else. If you decide DaaS
When looking at desktop virtualization methods, it's not about Desktop as a Service (DaaS) vs. VDI vs. RDSH. First you have to choose whether data center-hosted technologies such as virtual desktop infrastructure (VDI) and Remote Desktop Session Host (RDSH) are appropriate for your use, and then decide whether to host them yourself or use a DaaS provider.
Of course, it's not that easy. Although using a cloud service provider means you don't have to handle some of the management and security, there are still things you have to account for with hosted virtual desktops. Let's take a look at some of the considerations you need to keep in mind when evaluating Desktop as a Service.
Integrating hosted virtual desktops into your environment
First, you'll need to consider integration: How do you hook your desktop solution into your data center? This assumes that you have some sort of infrastructure in place ahead of time. If you're a small company with only a small domain and perhaps an email server, you could move your email to Gmail and your domain to a cloud service provider (CSP) that offers Desktop as a Service.
That's an uncommon scenario, though, so how do you go about integrating DaaS into your environment? If it were just desktops you cared about, you could use whatever secure gateway the DaaS provider's platform offers. But odds are you have applications and files that exist locally and need to be accessed from both the cloud and local machines -- not to mention Active Directory. That means you need a virtual private network (VPN), but that's only the start.
More on hosted virtual desktops
Guide to cloud-hosted desktops and apps
Deciding to put virtual desktops in the cloud
How cloud-based desktops can cut costs
Regarding Active Directory, should you use your existing domain or the CSP's domain? Do you want to set up a trust between their domain and yours to provide access to local resources? Do you trust that scenario? If you use your own domain, should you authenticate over the WAN or place a domain controller on-site at the hosted virtual desktop provider? The answer is different for each use case because it's based on personal preferences, best practices and your own company policy.
Once you work past that, consider how you work with applications and data. If you use a large enterprise resource planning (ERP) and the data lives in your data center, for instance, you need to rely on the VPN for communication between the app and the data. You can change that, but it adds cost and complexity.
The users' files and profiles come with similar challenges. If the file shares exist in the local data center, that means you're transferring files across the VPN (the same one that you're trying to deliver desktops over).
None of these issues with hosted virtual desktops are insurmountable, but admins often don't consider them up front. Perhaps the answer is even outsourcing your entire infrastructure (Infrastructure as a Service), but that's a bit beyond the scope of this article!
With DaaS, not only do you need an Internet connection that's sized appropriately to handle all the remote protocol traffic, but it also has to accommodate the aforementioned data transfers. That translates to a beefy Internet pipe with a reliable, optimized connection. Perhaps you're already there, but if you're a small business or you have branch offices with smaller or unreliable connections, you need to factor this into your hosted virtual desktop costs.
The same goes for the CSP's connection. They will probably have multiple different Internet connections to service their customers, and you might consider adding some redundancy of your own. The hosted virtual desktop provider can help you determine how much bandwidth, redundancy and optimization you need.
Licensing for DaaS
When it comes to DaaS, the price you get from the provider is almost always exclusive of the licensing costs. DaaS is essentially a bring-your-own-license technology.
You're responsible for buying Software Assurance and/or Virtual Desktop Access licenses for Windows virtual desktops. The only place this isn't true is with a hosted RDSH environment. Windows Server has a Service Provider License Agreement that says CSPs can be used to deploy desktops to different companies on the same hardware. VDI is basically governed by the same licensing rules that any company has, which complicates matters when trying to use DaaS-based VDI for a small number of users.
The bottom line is to make sure you figure Windows licensing into your hosted virtual desktop cost model.
Keep an eye out next week for part two of my considerations for Desktop as a Service. We'll cover end-user access, control issues and confidence in your DaaS provider.
This was first published in November 2012