What Is Virtual Desktop Infrastructure (VDI)?^{1 2}

What Is Virtual Desktop Infrastructure (VDI)?

VDI refers to abstracting and hosting numerous virtualized desktop sessions on a centralized, back-end server. These virtual desktops are then made accessible to users through thin client endpoints. (Thin client devices are typically cost-efficient PCs with minimal hardware, designed for one task or a few functions.) VDI has been around for over a decade and is a common method of providing a high number of repeatable endpoint experiences to a large workforce. Global disruptions such as COVID-19 mean that businesses need to be ready to support a massive remote workforce at short notice, and many IT decision-makers are looking with renewed interest at VDI as a potential solution to abstract the entire desktop or a subset of its applications.

How Does VDI Work?

In a VDI configuration, a central server hosts the entirety of the virtual desktop, including OS and apps. The server uses remote procedure call (RPC), a series of functions that facilitate communication to and from end clients. System administrators use an RPC orchestrator on the server to configure the virtualized desktop environments, select which apps are available, and establish settings and permissions for the operating system (OS). End users will then individually connect to the server and access a virtualized desktop environment through their client PC. Usually, the endpoints in a VDI configuration will be thin clients, which are PCs with an ultralightweight configuration: just enough processor speed and RAM to perform a few functions, built for a closed corporate LAN network.

However, as the VDI model is evolving, new configurations are exploring the potential for supporting VDI over the cloud to PCs and rich end clients outside the corporate firewall. A key example of this is Windows Virtual Desktop, which Microsoft supports through the Azure cloud service. Windows Virtual Desktop provides a full Windows 10 experience with Microsoft 365 apps, enabling more variety in productivity or interactivity compared to traditional VDI with stationary thin clients. Accordingly, the end user device for a Windows Virtual Desktop setup may offer a full PC or laptop experience with more-robust specifications, including a faster processor, Wi-Fi, and integrated graphics. Microsoft also hosts the infrastructure for Windows Virtual Desktop, so businesses don’t need to invest in or manage server infrastructure to support the solution. Businesses can be up and running faster, and they spend less on maintenance and overhead.

Persistent and Nonpersistent VDI

There are categories of VDI deployments known as “persistent deployments” and “nonpersistent deployments.” Persistent VDI refers to VDI configurations that preserve end user settings and files each time the user logs out or shuts down their PC. Nonpersistent VDI locks down the virtual desktop such that any changes introduced by the end user are discarded at the end of each session. Saved files are wiped clean, configuration settings are reverted to default, and any unintentional change like downloaded malware is erased. Nonpersistent VDI can be used in an environment where endpoint PCs and terminals are publicly shared and there is no need to preserve user profiles from one login instance to the next.

VDI vs. Desktop Virtualization

Desktop virtualization is a method that allows workers to remotely access and run applications on a desktop workspace from a separate device. A common scenario is when a worker logs into their office PC from their home PC using remote access software. Desktop virtualization may also refer to running multiple virtual machines (VMs) on a single device in order to keep workloads separate and isolated. A common example of desktop virtualization is when a worker runs two separate VMs on their PC: one VM for professional and business use and one VM for personal use.

VDI is different from desktop virtualization in that desktop virtualization is decentralized. It generally refers to accessing or managing VMs between one or more devices. VDI is a centrally managed, locked-down environment where all virtual desktops are hosted on a back-end server.

VDI Use Cases

VDI can be useful to any industry that is looking to implement a highly repeatable end user experience at scale. Here are a few key examples:

• Banking and financial institutions: VDI allows banks to tightly control what information their endpoint systems can access. This level of control makes it easier to handle sensitive financial transactions under a heavily scrutinized and regulated environment.
• Hospitals and healthcare environments: Hospitals also handle confidential information and must abide by complex regulations such as HIPAA in the United States. Additionally, nurses and doctors are highly mobile in a healthcare environment, moving from thin client to thin client throughout the workday. A VDI implementation allows users to cycle in and out of different profiles on the same device while keeping information siloed and helping meet privacy requirements. VDI can also offer context-specific access methods, like two-factor authentication or badge swiping, to help secure and track user access from terminal to terminal.
• Call centers: Call centers benefit greatly from lightweight, cost-effective endpoints for their workers. In these business environments, PCs typically only need to run a single app for call routing and response. VDI servers help simplify management requirements with a centralized point of control. The result is that call-center businesses can scale up their workforce and strike a balance between capacity and efficiency.
• Remote access: Remote workforces are increasingly becoming the norm. However, remote workers need more flexibility and performance in their endpoint PCs to support modern work practices: email, web browsing, word processing, and videoconferences. In these cases, businesses need a rich client experience and full desktop capabilities, such as those found in Windows Virtual Desktop.

Benefits of VDI

VDI is useful in any scenario where an organization needs to lock down company data or limit end user functions to a singular purpose or mode of productivity. The following is a list of benefits in a traditional VDI use case, but as previously stated, the model is evolving to accommodate richer remote online experiences.

• Centralized management: Because VDI servers are centrally controlled, it’s easier for a system administrator to maintain, update, or deploy new apps through the RPC orchestrator. As a result, administrators do not need to update end user devices individually.
• More-secure data: In a VDI setup, nothing is stored locally on the endpoint device. All data and apps remain on the server, so it is easy for a company to lock down its data and help protect it from unauthorized access.
• Congruent user experiences: The VDI experience is the same for every end user who logs into a virtualized desktop: the same apps, the same OS settings, the same permissions.
• Cost-effective endpoints: Because endpoints in a VDI implementation are designed to fulfill just one or a few functions, the endpoint devices themselves can be very stripped-down, lightweight, low-cost configurations. (This scenario does not typically apply when using rich clients and a hosted virtual desktop solution like Windows Virtual Desktop.)
• Highly customizable: VDI implementations leave it up to the business to decide which apps should be installed on the endpoint devices. Perhaps workers need access to a SaaS-based HR software, so companies might then include browser functionality to open endpoints up to the rest of the world.
• Extend legacy investments: VDI is also a viable option anytime a business needs to use software beyond its official end of life. For example, if a business has a legacy app that only runs in Windows 7, the business can set up a VDI environment that’s tightly controlled and not exposed to external network access.

VDI Technology Requirements

Traditional VDI implementations are composed of one or more central servers and a number of lightweight endpoint devices. However, as workloads and multitasking are increasing in volume and scope, endpoints need to become more robust and offer richer end user experiences.

The challenge with deploying rich clients in a VDI environment is that the more capabilities you add to an endpoint device, the harder it is to manage centrally and the more expensive it gets. This is especially true when you take endpoint devices outside the corporate firewall. As more and more businesses are turning to VDI and solutions like Windows Virtual Desktop to equip and enable their remote workforces, there is a greater need for remote manageability platforms to make it easier to access and secure these devices.