What is a virtual machine? |How does virtualization work? |Types of VMs and their merits and disadvantages.

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VMs (Virtual Machines)

An introduction to Virtual Machines (VMs), the technology used to create virtualized computing environments that served as the foundation for the first generation of cloud computing.

What exactly is a virtual machine (VM)?

A virtual machine is a virtual replica of a physical computer, often known as emulation. They are frequently referred to as a guest, whilst the actual computer on which they run is referred to as the host.

On a single physical machine, virtualization allows you to create several virtual machines, each with its own operating system (OS) and applications. A virtual machine (VM) cannot communicate with a physical computer. Instead, a lightweight software layer known as a hypervisor is required to coordinate between it and the underlying physical hardware. Each VM is given physical computing resources, such as processors, memory, and storage, via the hypervisor. It separates each VM from the others so that they do not interfere with one another.

While this technology is known by many different names, including virtual server, virtual server instance (VSI), and virtual private server (VPS), we will simply refer to them as virtual machines in this article.

How does virtualization work?

When a hypervisor is used on a physical computer or server (also known as a bare metal server), it allows the operating system and programmes to be separated from the hardware. It may then partition itself into multiple distinct "virtual computers."

Each of these new virtual machines may then run its own operating systems and programmes while still sharing the original resources from the bare metal server, which is managed by the hypervisor. Memory, RAM, storage, and other resources are examples of such resources.

The following video illustrates the fundamentals of virtualization, and be sure to read the article "5 Benefits of Virtualization":

VM Advantages and Benefits :

Virtual machines have various advantages over traditional physical hardware:

Improved ROI and resource utilisation: Because many VMs operate on a single physical machine, users don't have to buy a new server every time they wish to run another OS, and they can get more out of each piece of hardware they currently possess.

Scalability: With cloud computing, it's simple to deploy numerous copies of the same virtual machine to better accommodate spikes in load.

Portability: VMs may be moved around among physical computers in a network as needed. This enables tasks to be distributed to servers with excess processing capability. VMs may even migrate between on-premises and cloud environments, making them valuable in hybrid cloud scenarios where computing resources are shared between your data centre and a cloud service provider.

Flexibility: Because you can clone a VM with the OS already installed, creating a VM is faster and easier than installing an OS on a physical server. On-demand environments can be created by developers and software testers to handle new jobs as they emerge.

Security: When compared to operating systems that operate directly on hardware, virtual machines improve security in various ways. A virtual machine (VM) is a file that may be examined for malicious malware using an external tool. You may take a whole snapshot of the VM at any point in time and then restore it to that state if it becomes infected with malware, effectively rewinding time. Because VMs can be created quickly and easily, it is feasible to entirely erase a compromised VM and then immediately reconstruct it, which speeds up recovery from malware attacks.

Case Studies for Virtual Machines :

 

Virtual machines (VMs) have a variety of applications for both business IT managers and end users. Here are a few possibilities:

Cloud computing: For the last ten years or more, virtual machines (VMs) have been the core compute unit in the cloud, allowing dozens of different types of applications and workloads to function and expand successfully.

Support DevOps: Virtual machines (VMs) are an excellent approach to assist corporate developers, who may customise VM templates with the settings for their software development and testing procedures. They can establish virtual machines (VMs) for specialised activities such as static software testing, and include these procedures into an automated development cycle. All of this contributes to the simplification of the DevOps toolchain.

Test a new operating system: A virtual machine (VM) allows you to run a new operating system on your desktop without impacting your current OS.

Investigate malware: Virtual machines (VMs) are important for malware researchers who regularly require new computers on which to test dangerous applications.

Use incompatible software: Some users may prefer one operating system while yet requiring an application that is only accessible in another. The Dragon line of voice dictation software is a notable example. Nuance, its provider, has terminated the macOS version of its programme. However, using a desktop-focused hypervisor, such as VMware Fusion or Parallels, allows you to run Windows in a virtual machine (VM), allowing you access to that version of the programme.

Browse safely: Using a virtual computer for browsing allows you to view websites without fear of infection. After each browser session, you may take a snapshot of your system and then roll back to it. This is something that a person may do on their own by utilising a Type 2 desktop hypervisor. Alternatively, an administrator might set up a temporary virtual desktop on the server.

VM Classifications :

This section describes some of the several types of virtual machines:

-Windows virtual machines

-Android virtual machines

-Mac virtual machines

-iOS virtual machines

-Java virtual machines

-Python virtual machines

-Linux virtual machines

-VMware virtual machines

-Ubuntu virtual machines

Single-tenant vs. multi-tenant :

Virtual computers in the cloud are often available in both single-tenant and multi-tenant configurations.

Public virtual machines, also known as multi-tenant virtual machines, are virtual computers in which numerous users share the same physical infrastructure. This is the most cost-effective and scalable method of deploying virtual machines, but it lacks several isolation features that enterprises with strong security or compliance demands may want.

Dedicated hosts and dedicated instances are the two models for single-tenant virtual machines.

A dedicated host entails renting a full physical machine and keeping continuous access to and control over that system, its hardware, and any software that is installed on it. This approach gives the most hardware flexibility and transparency, as well as workload control and allocation, and it has some advantages for particular licencing software.

Models of pricing for virtual machines :

              

Pay-as-you-go (by the hour or second), transient/spot instances, reserved instances, and dedicated hosts are the most prevalent pricing structures for virtual machines in the cloud.

Pay-as-you-go: There are no upfront expenses for the virtual machine under the pay-as-you-go model, and customers simply pay for what they use, which is often invoiced by the hour or second depending on the provider and instance type.

Transient/spot instances: The cheapest VM option, transient and spot instances take use of a provider's spare capacity but can be retrieved at any moment by the provider. They are often appropriate for applications that do not require continuous operation or are prohibitively costly in any other type.

How to Select a Provider of Virtual Machines :

               

Choosing a virtual machine and cloud provider does not have to be difficult if you know what to look for. Of course, the virtual machine must meet your workload requirements and company budget, but other aspects also play important roles between you and your virtualization environment. The following are 10 factors to consider when choosing a virtual machine service provider.

Reliable assistance - Ensure that customer service is available 24 hours a day, seven days a week by phone, email, and chat, or walk away. You want a live person on the other end of the phone to assist you in crucial IT problems. It's also worth noting whether cloud providers give supplementary services for more hands-on support.

Managed alternatives – Does the cloud provider provide both unmanaged and managed solutions? If you are unfamiliar with virtualization technology, consider hiring a provider that will be in charge of setup, maintenance, and continuous performance monitoring.

Integration of software - Will your virtual machine environment work nicely with others? Operating systems, third-party software, open source technologies, and apps enable you to provide additional solutions throughout your organisation. You'll want a virtual machine provider who supports and has strong connections with the industry's most popular software vendors. Keep in mind that vendor lock-ins should be avoided.

Excellent network and infrastructure — How current is the infrastructure on which your new virtual machine will run? This comprises durable bare metal servers, cutting-edge data centres, and a strong network backbone. A cloud provider should be able to deliver on its end of the bargain using cutting-edge hardware and high-speed networking technologies.

Location, location, location - The closer the data is to your users, the less trouble you'll have with latency, security, and service delivery. A solid global network of dispersed data centres and point-of-presence (POP) sites is critical to have data where and when you need it.

Backup and recovery - What plans does your cloud provider have in place to keep your virtual machines operational in the case of an unforeseen occurrence? Do they also provide backup and redundancy alternatives for your virtualized environment? You should take continuous operation seriously.

Scalability ease – How quickly and easily will you be able to spin up, spin down, reserve, stop, and upgrade your virtual machine? When it comes to virtual machine scalability, the term you want to hear most is "on-demand."

CPU configurations – The more combinations, the better. Not every virtual machine configuration is appropriate for every workload at every time of year. Make sure to seek for a virtual machine supplier who offers a variety of configuration options for both single and multi-tenant requirements.

Layers of security – Inquire with your provider about them, then inquire again. When dealing with sensitive customer information, your company data is cash in the highest form. Private network connections, federal data centre alternatives, built-in encryption capabilities, and regulatory compliance standards are all critical for safeguarding your most important asset.

Support for seamless migration - Your IT priorities will constantly change. We are all aware of this. Any virtual machine supplier should be able to assist you with the lifting and shifting of virtual machines between hybrid, on-premise, and off-premise settings. Look for alternatives for complete data intake, over-the-network migration, and application-led migration.