Virtualization is the foundation of cloud computing, allowing cloud providers to offer scalable, on-demand resources to users. It is the key technology that helps efficiently allocate and manage hardware resources.
First Things First: What is Virtualization?
Virtualization is a smart technology that makes a virtual version of something, usually computer resources like hardware, storage, or networks. Think of it as a software layer on top of your physical hardware that lets you run multiple separate environments on one machine. Most commonly, it refers to running multiple operating systems on a computer system simultaneously.
To the applications running on the virtualized machine, it feels like they are on their own dedicated machine. The operating system, libraries, and other programs are unique to the guest virtualized system and are separate from the host operating system below it.
Let's take a simple example of virtualization:
Consider a company that needs servers for three functions:
Store business email securely
Run a customer-facing application
Run internal business applications
Each of these functions has different configuration requirements:
The email application requires more storage capacity and a Windows operating system.
The customer-facing application requires a Linux operating system and high processing power to handle large volumes of website traffic.
The internal business application requires iOS and more internal memory (RAM).
Traditionally, to meet these needs, the company sets up three separate physical servers for each application. This requires a large initial investment and ongoing maintenance for each server. The company also can't fully use its computing power. It pays for all the maintenance costs but only uses a small part of the servers' storage and processing capacities.
This is where virtualization comes in-
Efficient hardware use:
With virtualization, the company creates three digital servers, or virtual machines, on one physical server. It sets the operating system requirements for each virtual machine and uses them just like physical servers. However, the company now has less hardware and fewer related costs.
Infrastructure as a service:
The company can take it a step further by using a cloud instance or virtual machine from a provider like AWS. AWS handles all the hardware, and the company can ask for server resources with different setups. All the applications run on these virtual servers without users noticing any difference. This also makes server management easier for the company’s IT team.
Concepts in virtualization
Virtualization uses specialized software, called a hypervisor, to create several cloud instances or virtual machines on one physical computer.
Virtual machine:
A virtual machine (VM), often shortened to just VM, is essentially a computer created entirely through software. Think of it like a virtual world within your physical computer. While a physical computer has tangible parts like CPU, memory, and storage, a VM simulates these components using software.
You can use virtual machines just like other applications on your computer. Your computer is the host, and the virtual machine is the guest. Multiple guests can run on the host. Each guest has its own operating system, which can be the same or different from the host's operating system.
Here are some common uses of VMs:
Running different operating systems: You can use VMs to test software designed for different operating systems (Windows, Linux, etc.) without needing multiple physical machines.
Consolidating servers: By virtualizing servers, companies can run multiple servers on a single physical machine, saving space and energy costs.
Creating development and testing environments: Developers can use VMs to create isolated environments to develop and test applications without affecting production systems.
Providing virtual desktops: Virtual desktops allow users to access a desktop environment remotely from any device, improving accessibility and security.
VMs are a core component of cloud computing. Cloud providers use virtualization to create a pool of virtual machines that they can rent out to users on-demand. This allows users to scale their resources up or down as needed, paying only for what they use.
Hypervisor:
A hypervisor, also sometimes called a virtual machine monitor (VMM), is the software that actually creates and manages virtual machines (VMs).It acts like the conductor of an orchestra, overseeing the allocation of resources and ensuring everything runs smoothly within the virtualized environment.
Here's how a hypervisor functions:
Creates VMs: The hypervisor uses the physical server's resources (CPU, memory, storage) and divides them into separate units. It then creates virtual machines on these units, each with its own resources.
Manages Resources: The hypervisor sits between the VMs and the physical hardware. It controls how VMs use the physical resources, making sure each VM gets its share and no VM uses more than it should.
Provides Isolation: The hypervisor keeps VMs separate from each other. This means a problem in one VM won't affect other VMs on the same server, improving security and stability.
Security Features: Hypervisors can include security features like secure boot and memory isolation to protect VMs from unauthorized access or malware.
There are two main types of hypervisors:
Type 1 Hypervisor (Bare-metal Hypervisor): This type of hypervisor runs directly on the physical server's hardware, without relying on an underlying operating system. It has direct access to the hardware resources, offering better performance and security.
Type 2 Hypervisor (Hosted Hypervisor): This type of hypervisor runs on top of an existing operating system like Windows or Linux. It's less resource-intensive than a bare-metal hypervisor but might have slightly lower performance.
Virtualization: The foundation of Cloud Computing
Virtualization acts as the magic trick that allows cloud providers to offer scalable, on-demand resources to users. Here's how:
Resource Pooling: Virtualization software creates virtual machines (VMs) that act like physical servers. Multiple VMs can run on one physical server, letting cloud providers share their hardware and serve many customers at the same time.
Isolation and Security: Each VM runs in its own separate environment, with its own operating system and applications. This separation ensures that applications on different VMs don't affect each other and provides a level of security.
Scalability and Elasticity: Cloud users can quickly increase or decrease their resources by adding or removing VMs as needed. Virtualization makes this on-demand allocation possible, so users only pay for what they use.
Flexibility and Cost-Effectiveness: Cloud providers can offer a wide range of VM configurations with varying processing power, memory, and storage. This flexibility lets users pick the best VM for their needs, avoiding the cost of buying too much physical hardware.
Management and Efficiency: Virtualization tools make server management easier for cloud providers. They can quickly set up, move, and manage VMs across their systems, which boosts efficiency and makes better use of resources.
In essence, virtualization unlocks the true potential of cloud computing by:
Transforming physical servers into a pool of on-demand resources.
Allowing multiple users to share the same hardware securely.
Making it easy for users to adjust their resource needs.
Cloud computing leverages virtualization to provide a dynamic and cost-effective way to access computing resources. It's like having a vast pool of computing power available at your fingertips, accessible and adaptable to your specific needs.