Virtual Desktop Infrastructure

VDI Software: What It Is and How It Works

[Cloud Volumes ONTAP, Elementary, 7 minute read, VDI, Virtual Desktop Infrastructure]

Virtual desktop infrastructure (VDI) technology enables remote management of virtual desktops. VDI deployments can provide you with the entire backend components, including operating systems, hypervisors, desktop image management, storage, layering and networking. You can also use thin client workstations, which come with zero or minimal VDI backend management.

In this post, we’ll explain how VDI software works, and examine offerings by key thin client VDI vendors. We will also show how NetApp Cloud Volumes ONTAP can help make VDI software deployments cost-effective, highly available, and easy to orchestrate.

In this article, you will learn:

What Is Virtual Desktop Infrastructure (VDI)?

VDI is a technology that enables you to deploy desktops to client devices from virtual machines. Using VDI you can centrally manage and store all desktop data while enabling remote access on most devices, including tablets, thin clients, workstations, browsers, and mobile devices. VDI is also sometimes referred to as end-user computing (EUC).

How Does VDI Software Work?

VDI deployments bundle all of the components needed to use desktops and applications along with networking and storage resources. Below you can learn how these components operate to enable virtual desktop functionality.


Operating system

You can base VDI deployments on a self-contained OS or on a host OS. Most commonly, VDI uses self-contained systems, with each virtual machine (VM) or instance containing its own OS copy.

With self-contained systems, the OS is centrally managed and duplicated as many times as needed to serve desktops. Each desktop it serves can be used on a 1:1 basis, tied to a single user, or a 1:many, available to multiple users. When VMs are deployed, any necessary applications or add-on functionality is included before the desktop is delivered.

With workstation-based deployments, the OS is stored on the workstation and the desktop is delivered only with applications and add-ons. These desktops then rely on the local OS to operate. Previously this method only allowed for 1:1 use but the release of Windows Virtual Desktop (WVD) enables multi-users as well.


Hypervisor

Hypervisors are software or hardware used to host and manage your VMs. Some VDI deployments, such as Microsoft RDS and Citrix Virtual Apps can be implemented with any hypervisor. Others, such as VMWare Horizon, require a proprietary hypervisor.


Desktop image management

Desktop images are blueprints for what desktops should contain and how they should be set up. Image management involves ensuring that images are up to date, properly licensed, and correctly distributed. Another aspect of image management is sharing images across teams or partnerships.


Storage

Storage resources are needed to host machine images and provide working storage for desktops. You can allot storage with either thin or thick provisioning. Thin provisioning uses the minimum amount of storage and expands as needed. Thick provisioning sets aside the amount of storage potentially needed.

Related content: read our customers case studies with VDI storage.


Layering

Layers enable IT teams to easily manage sets of applications or utilities. With layers, administrators can deliver desktops from a standardized base image that include functionalities matching different users. Layers enable these customized desktops without requiring the creation of additional images.


Networking

VDI technology requires networking to deliver desktops to end users. To keep data and communications secure, you should encrypt these networks using Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols.

Persistent vs Non-Persistent VDI

One decision you need to make in terms of user experience and resources in VDI is whether to deploy persistent or non-persistent desktops.

Persistent VDI

Persistent desktops more closely mimic all the functionality of local desktops because these provide customizable workspaces for a single user. With a persistent desktop, users can store data, change configurations, and personalize operations. To enable this functionality, desktops must have dedicated storage. Additionally, if you do not persist VMs, you need to create backups for restoration before the VM is shut down.

Pros of persistent desktops include:

  • Easier to personalize or adapt to user preferences
  • Transition from traditional desktops is more transparent for users

Cons of persistent desktops include:

  • Requires more storage resources and more complex access permissions
  • Management is more difficult since you have more images to account for

Non-Persistent VDI

Non-persistent desktops are generic desktops that are not tied to a specific user. Instead, a randomly available or newly created desktop instance is delivered on demand. These desktops do not save personalization or data, requiring users to export any data they need to save.

Pros of non-persistent desktops include: 

  • Images are easier to update and manage since only one or two master images is needed
  • Desktops are more secure since users cannot permanently alter configurations or install potentially malicious software
  • Less dedicated storage is required

Cons of non-persistent desktops include:

  • Not as user friendly since users can’t personalize desktops
  • Users may need more permissions to adapt sessions to their specific needs
  • May require application or environment virtualization to meet the needs of all users

Thin Client Support Across VDI Vendors

Thin clients are workstations with no or minimal local storage and no local OS; essentially monitors and peripherals connected to a network. When implementing VDI, thin clients are often considered because the management and maintenance these devices require is minimal.

If you are using thin clients with your VDI implementation it is important to understand what support different virtualization vendors provide. Understanding this support can help you ensure that your vendor matches your existing hardware or can inform your future hardware purchases.


Azure Windows Virtual Desktops (WVD)

WVD is the evolution of VDI support from Microsoft’s existing Remote Desktop Services. This service is hosted on Azure and uses the Remote Desktop Protocol (RDP) to deliver desktops using Windows 10 to thin clients.

If using a different OS version, you can also use third-party services, such as IGEL. This service enables thin client use with any Windows OS and can universally convert desktops for VDI.


Amazon WorkSpaces

Amazon WorkSpaces is a subscription service hosted in AWS. This AWS VDI service is available for a variety of platforms, including Windows, Linux, macOS, Android, and iOS. You can use WorkSpaces with both thin and zero clients. However, thin clients do not support most peripherals, including USB storage devices, webcams, and printers.


Citrix clients

Citrix supports three categories of thin clients, all based on high-definition experience (HDX) technologies. Support for these are provided directly through Citrix or through Citrix partnerships, such as with IGEL.

  • HDX Ready—designed for entry level users and applications or software with minimal resource demands.
  • HDX Premium—designed for standard users with typical desktop applications and workloads. For example, you can use these clients for high-definition video conferencing which is not supported by Ready.
  • HDX 3D Pro—designed for organizations and users with graphically intense applications. For example, these clients can support workloads with 3D graphics or those using computer-aided design applications.

VMware Horizon

VMware Horizon is a VDI platform that you can use on-premises or in the cloud. Depending on the version you use, you can access basic VDI capabilities (with Horizon Standard) or support for advanced capabilities, including thin clients.

To use thin clients, you need either Horizon Advanced or Horizon Enterprise. Advanced provides access to unified workspaces, Remote Desktop Session Host, software as a service (SaaS) integration, and VMWare ThinApp support. Enterprise expands access to support for virtual storage area networks, Linux support, and utilities for health and performance monitoring.

VDI Software Management with Cloud Volumes ONTAP

NetApp Cloud Volumes ONTAP, the leading enterprise-grade storage management solution, delivers secure, proven storage management services on AWS, Azure and Google Cloud. Cloud Volumes ONTAP supports up to a capacity of 368TB, and supports various use cases such as file services, databases, DevOps or any other enterprise workload, with a strong set of features including high availability, data protection, storage efficiencies, Kubernetes integration, and more.

To find out more about VDI deployment in the cloud and how Cloud Volumes ONTAP can help you run your VDI environment on cloud resources, download our guidebook on Virtual Desktop Infrastructure in the Cloud. You can also learn about case studies of major companies who turned to Cloud Volumes ONTAP to make their VDI deployments cost-effective, highly available, and easy to orchestrate with the flagship NetApp cloud solution.

NetApp’s Virtual Desktop Service (VDS) is a global control plane for virtual desktop management that functions as an extension of the cloud. VDS supports Remote Desktop Services (RDS) on Azure, AWS, GCP as well as on-premise environments. It also provides native support for Microsoft's Windows Virtual Desktop (WVD) solution in Microsoft Azure. To learn more visit the NetApp VDS solution page.

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