Desktop Virtualisation

Desktop Virtualization (DV)

Desktop Virtualization (DV) is a technique that creates an illusion of a desktop provided to the user. It delivers either a single application or an entire desktop environment to a remote client device.

• Function: It's a software technology used to separate the desktop and its connected application software from the physical device used by the client.

• Mechanism: It works similar to a client-server model, where applications are executed on a remote desktop with different operating systems, and a user interacts with the application via a remote display protocol.

• Key Advantage: Unlike traditional desktop administration, which is often expensive and time-consuming, DV allows IT staff to alter, update, and organize the desktop elements independently of the hardware, leading to greater business quickness and improved response time.

Components for Desktop Virtualization (VDI Architecture)

The DV architecture often follows the Virtual Desktop Infrastructure (VDI) model and consists of several components working together for an end-to-end solution:

1. Endpoint Devices: The physical hardware (like laptops, thin clients, or tablets) used by the user to access the remote desktop.

2. Connection Broker: The software component that authenticates the user and connects them to the appropriate available virtual desktop/VM Host.

3. VM Hosting: The remote servers (in the data center/cloud) where the virtual desktops (Virtual Machines) are hosted and executed.

Techniques Used for Desktop Virtualization

There are three typical techniques used to deliver a virtual desktop experience:

1. Remote Desktop Services ($\text{RDS}$): Traditionally from Microsoft, this allows multiple users to share a single server's OS instance, each getting a separate session-based desktop.

2. Virtual Desktop Infrastructure ($\text{VDI}$): This is where each user is provided with a dedicated virtual machine (VM) running its own operating system from the data center.

3. Desktop-as-a-Service ($\text{DaaS}$): A cloud service model where a third-party provider hosts the entire VDI infrastructure and streams the desktop to the user over the internet.

1. Remote Desktop Services (RDS)

RDS, formerly known as Microsoft Terminal Server, is primarily used for providing services to users and is a cost-effective desktop virtualization option.

Key Characteristics:

• It is customarily called terminal services.

• It allows consumers to distantly access Windows applications and graphical desktops.

• It is also known as Remote Desktop Session Host (RDSH).

• Applications and desktop images are served via the Microsoft Remote Desktop Protocol (RDP).

• Cost-Effectiveness: Since one instance of Windows Server OS can support many simultaneous users as the server hardware can handle, RDS is a more cost-effective choice than VDI.

Advantages of RDS:

• Data recovery in tragedy (Disaster Recovery).

• Operation from any place (Remote Access).

• Economical (Cost-effective).

Disadvantages of RDS:

• Requirement of powerful RDS server hardware.

• Requirement of RDS monitoring tools.

• Requirement of a reliable network.

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2. Virtual Desktop Infrastructure (VDI)

VDI refers to the hosting of a desktop OS running in a Virtual Machine ($\text{VM}$) on a server in the virtual data center (VDC).

Key Characteristics:

• VDI allows a user to access a remote desktop environment from an endpoint device via a remote desktop delivery protocol.

• The desktop image travels over the network to the end user's device, making it seem as if the user is interacting with a local machine.

• Dedicated Resources: VDI gives each user their own dedicated VM running its own operating system.

• Resource Management: A hypervisor layer manages the resource allocation (drivers, CPUs, memory, etc.) to multiple VMs and ensures they run side by side on the same server.

• Windows 10 Delivery: A key benefit is its ability to deliver the standard Windows 10 desktop and operating system to the end user's devices. However, because VDI supports only one user per Windows 10 instance, it is generally less cost-effective than RDS.

Advantages of VDI:

• Low price in buying desktop computers (Since users can use cheaper thin clients/endpoint devices). successful

• Centralized client operating system management.

• Reduction in the costs of desktop and electricity.

• Enhanced security of data and protected remote access.

• Lesser applications compatibility troubles.

• Disadvantages of VDI

  • Printing normally involves third-party appends (extra steps or software).

  • Scanning is natively unsupported or difficult.

  • Bi-directional audio is natively unsupported (microphone/speakers issues).

  • Exhibit protocols are unsuitable for graphic design or other high-demand graphical applications.

  • Needs low-latency association between the virtual infrastructure and the customer (requires excellent network speed).

  • Needs enterprise class server hardware and storage area network for VMs permanently delivered to particular users.

  • Needs trained IT staff.

• Sr. No.	Remote Desktop Services ($\text{RDS}$)	Virtual Desktop Infrastructure ($\text{VDI}$)
  1.	Separate virtual machines are not provided to the user.	Separate virtual machines are provided to the users (one VM per user).
  2.	Multiple operating systems instances need not be managed (since all users share one server OS).	Multiple operating systems instances need to be managed (one OS per VM).
  3.	Various users share the same virtual machines and operating systems.	Same resources need not be shared (users get dedicated VM resources).
  4.	Full administration is not provided to the users because many instances of the same resources are shared.	User gets full administration over resources.
  5.	Less resource utilization of $\text{CPU}$, memory elements, etc. (More efficient per-user).	More resource utilization (Less efficient per-user due to dedicated $\text{VM}$).

  
  
• Benefits of Desktop Virtualization

• Desktop Virtualization significantly simplifies the management of employee computing needs for IT teams.

  • Template-Based Management: Instead of individually maintaining numerous physical computers, the business can manage a single Virtual Machine ($\text{VM}$) template for employees who share similar roles or functions.

  • Centralized Updates: Any software changes, such as reconfiguration, updates, or patching, are applied once to the central VM template.

  • Efficiency: This process eliminates the need to perform the same update process repeatedly on every individual physical computer, resulting in substantial savings in time and IT resources.

• Cost Savings:

  • Allows IT budgets to shift from high Capital Expenditures ($\text{CAPEX}$) (buying new hardware) to predictable Operating Expenditures ($\text{OPEX}$) (like a regular usage-based charge for DaaS).

  • Extends the life of older or less powerful end-user devices (thin clients, etc.) because the intensive processing is done remotely on the data center VMs.

• Improved Productivity:

  • Makes it easier for employees to access enterprise computing resources.

  • Allows users to work anytime, anywhere, from any supported device with just an Internet connection.

• Support for a Broad Variety of Device Types:

  • Supports remote desktop access from a wide range of devices, including laptops, thin clients, tablets, and even mobile phones.

  • Delivers a consistent desktop experience regardless of the operating system native to the end-user device.

• Stronger Security:

  • The actual desktop image and data are separated and abstracted from the physical hardware used to access it.

  • The VM used to deliver the desktop is hosted in a data center, which is a tightly controlled environment managed by the IT department.

• Agility and Scalability:

  • It is quick and easy to deploy new $\text{VMs}$ or serve new applications whenever needed.

  • It is just as easy to delete them when they are no longer required, making the infrastructure highly responsive to business needs.

• Better End-user Experiences:

  • Users can enjoy a feature-rich experience without sacrificing necessary functionality they rely on, such as printing or access to USB ports (though these features may require additional configuration, as noted in previous sections).

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