Virtual desktop infrastructure (VDI) is as old as traditional virtualisation. In 2006, VMware announced the VDI Alliance with HP, IBM, Citrix and Sun Microsystems (now Oracle) among other companies. Since then, the virtualisation and VDI markets have matured to support evolving enterprise requirements. While public cloud has provided a logical transition for the virtualisation customers, VDI has been slow in moving to the cloud.
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Anyone who has implemented VDI with a few hundred desktops will agree it is complex to set up and manage the infrastructure. VDI deployment demands advanced skills in networking and storage. Microsoft’s licensing terms made it difficult for enterprises to deploy a model that aligned with their business needs. Providing VDI high availability and business continuity was an expensive and challenging task for the IT department. And, on top of all this, VDI couldn’t keep up with the pace of virtualisation.
BYOD and public cloud drive DaaS adoption
Amazon EC2 launched in 2008, bringing mainstream computing to the cloud. Since then, many server workloads have moved to the cloud. But it is only now that the industry has started witnessing the migration of desktops to the cloud. There are two important factors that are driving the cloud desktop phenomenon: The bring your own device (BYOD) trend; and the migration of enterprise workloads to the public cloud.
With the rapid increase in the use of devices such as phones, tablets and slates by consumers, the enterprise IT department has come under tremendous pressure to support employees using their own devices. Employees don’t really need a PC to get their work done. Knowledge workers want access to their data and applications on any device at any time.
The use of file-sharing and synchronisation services such as Dropbox, Box, Google Drive and Microsoft One Drive are on the rise. Documents and files can be accessed and edited across multiple devices. For accessing legacy applications that are available only on a Microsoft Windows desktop, they can login through a remote desktop client running on their devices. The trend is forcing enterprise IT departments to provide employees with secure access to data, applications and desktops.
The other important driver lies in the growth of enterprise application migration to the cloud. Legacy server workloads such as enterprise resource planning (ERP), customer relationship management (CRM), HR and payroll applications are moving to public and hybrid cloud. These applications are still based on client/server architecture, which demands a thick client running on a desktop, to access the server.
Since it is not practical to run the server on the public cloud and the client on the local infrastructure, enterprise IT wants to deploy desktops on cloud that lives close to the servers. This helps them deliver a better experience to users without compromising performance or security.
DaaS Deployment Models
Virtual desktops use the following deployment models:
- Presentation virtualisation: Presentation virtualisation is widely known as remote desktop hosted sessions (RDHS) or terminal services (TS). This is the most common deployment model found on public cloud. Each user gets a Windows desktop-like session that runs on a Microsoft Windows Server OS;
- Desktop virtualisation: This is based on the original VDI model in which each client desktop is provisioned as a dedicated virtual machine, running in a centralised infrastructure or locally, on a PC with a hypervisor;
- Application virtualisation: Application virtualisation deals with streaming application interfaces to client devices, instead of installing them locally. The application executes on a centralised server while rendering just the interface on the clients. This enhances the experience by optimising bandwidth. This is typically used in running multiple versions of the same application in isolation;
- Personal desktops: Personal desktops offer better control by offering users personalisation and customisation. Personalisation may include application settings, user-interface changes and file-system modifications;
- Pooled desktops: Pooled desktops deliver stateless desktops that are reset at the end of each session. This is used to assign desktops to temporary employees or users who access desktop in a kiosk mode.
The DaaS market landscape
Desktop as a service (DaaS) is one of the fastest growing cloud services delivery model. After a late start, the DaaS market is experiencing substantial growth, with suppliers such as VMware, Amazon, Microsoft and Citrix investing heavily in DaaS. With data and applications breaking the boundaries of desktops by becoming available on multiple devices, there is a new concept of integrated workspaces. Amazon WorkSpaces, Citrix WorkSpace Services and VMware Horizon are moving towards the concept of workspaces.
Here is a quick summary of the key DaaS providers:
- Amazon WorkSpaces: Announced earlier this year, Amazon WorkSpaces is a managed desktop service from AWS. This marked the official entry of Amazon into the application services targeting enterprises. With many server workloads moving to EC2 and VPC, enterprises can host desktops close to the server. Combined with Amazon Zocalo, Amazon WorkSpaces is emerging as a powerful DaaS platform;
- Citrix Workspace Services: As a leader in desktop and application virtualisation, Citrix has a proven track record with its XenDesktop and XenApp family of products. Although Citrix doesn’t own a public cloud or datacentre infrastructure, it is enabling its partner ecosystem to deliver DaaS to customers. Citrix Workspace Services can run on the datacentre infrastructure, public cloud, private cloud or hybrid cloud;
- Microsoft Azure RemoteApp: According to Microsoft, Azure RemoteApp is a cost-effective system for a fluctuating workforce or fast-changing business requirements. It is based on a presentation virtualisation model for delivering applications to a variety of platforms, including Windows, Mac OSX, iOS and Android devices. Azure RemoteApp doesn’t provide access to the full desktop, it just delivers the application, hiding the rest of the desktop interface;
- VMware Horizon DaaS: When it bought DeskTone, VMware expanded the Horizon and View family of products to the cloud. vCloud Air, VMware’s public cloud, provides the infrastructure for its DaaS platform. Horizon DaaS supports presentation virtualisation, personal desktops and hosted applications. By partnering with Google and NVIDIA, VMware is bringing powerful desktop applications to Chromebooks.
Currently the DaaS market is all about delivering Microsoft Windows desktops and applications to users. As Apple Macs gain acceptance of enterprises, it will be interesting to see if DaaS providers will bring OSX desktops to the cloud.
Janakiram MSV is a Gigaom Research analyst and the principal analyst at Janakiram & Associates. He is a regular contributor to Computer Weekly and can be followed on Twitter at @janakiramm