What is a Virtual Machine and How is it Used in Cloud Computing?

[fog37]

TL;DR Summary

understand virtualization

Hello,

I am about to create (should I say install?) a virtual machine (VM) on my Windows pc to experiment with Linux.
My understanding is that a VM is a "software" (or is it more properly a file? Or is it an image? I guess an image is just a big file?) that is run/managed by a hypervisor (another software) which is run by the primary operating system (Windows 10 in my case). Having a VM will allow me to quickly switch between Linux and Windows as if I had two different physical machines...

The VM is essentially a "virtual computer" inside my computer. An operating system (Linux in my case) running on top of another operating system (Windows).

I hear a lot about VMs in the context of cloud computing (Azure, IBM cloud, etc.). Does that mean that every individual customer (or a group of employees in a business) is using a VM every time they connect and use the cloud and its services? For examples, if someone uses Office 365 online on the cloud, are they essentially using a VM that then disappears after they stop using Office 365?
Or do the VMs exist as long as the cloud subscription exists?

Thanks as always.

 

[pbuk]

I am about to create (should I say install?) a virtual machine (VM) on my Windows pc to experiment with Linux.
My understanding is that a VM is a "software" (or is it more properly a file? Or is it an image? I guess an image is just a big file?) that is run/managed by a hypervisor (another software) which is run by the primary operating system (Windows 10 in my case).

You don't seem to be very clear about the meanings of the terms 'file', 'image' and 'software' but the differences are not important here so going into this in detail is just going to confuse things: I suggest you do some reading around these subjects elsewhere.

I assume you are talking about either VirtualBox or VMWare? These are both Type 2 Hypervisors. That link goes into some detail, but briefly this means that they are programs that run as Windows 10 applications.

Having a VM will allow me to quickly switch between Linux and Windows as if I had two different physical machines...

No, the Linux machine will always exist as a (possibly full screen) 'window' within Windows.

I hear a lot about VMs in the context of cloud computing (Azure, IBM cloud, etc.). Does that mean that every individual customer (or a group of employees in a business) is using a VM every time they connect and use the cloud and its services?

No, the term 'cloud computing' covers a lot of different services. Virtual machines are just one service offered by most vendors.

For examples, if someone uses Office 365 online on the cloud, are they essentially using a VM that then disappears after they stop using Office 365?

No, the cloud versions of Office 365 applications are not desktop versions running in virtual machines.

 

[DaveC426913]

I hear a lot about VMs in the context of cloud computing (Azure, IBM cloud, etc.). Does that mean that every individual customer (or a group of employees in a business) is using a VM every time they connect and use the cloud and its services? For examples, if someone uses Office 365 online on the cloud, are they essentially using a VM that then disappears after they stop using Office 365?

I login to a VMware system every day. A Windows virtual desktop is created each time I login and is destroyed an hour or so after I log out. (And, to my great chagrin, my login expires on a regular basis every couple of hours whether I am i the middle of typing or not).

Other people also login daily, and each gets their own VM created for them.

 

[fog37]

Thanks.

Correction on my part: I mean Windows 365 but wrote Office 365...

So Windows 365 is a VM on the cloud, a virtual computer with apps and computing power. Office 365 online is just a suite of applications (Word, Excel, etc.) on the cloud so it is not a VM...

For all practical purposes, the experience of using Office 365 would seem the same as using Windows 365: we are using a service online in the cloud instead of from our personal physical pc.
Azure also offers "virtual desktops". I am looking into it...DaveC426913, just for curiosity, your VM is a cloud machine. Is it for work? Why do you have it?
I am currently not interested in a cloud VM but, to start, on creating a VM on my own Windows pc to use Linux...

Thanks!

 

[lyuc]

Normally you install windows to your hard drive, and it runs "on the bare metal". Why we call it that I don't know, because I don't think silicon is a metal.

In a VM, you install windows to the hard drive, but another program (the hypervisor) runs it as a guest of your existing operating system. This means it'll be installed into a "virtual disk" that appears to it as a real disk, and to the host as a disk file. The host "passes through" the commands issued by the guest to the metal, and vice-versa, so the guest thinks it's running normally. It's like it's in the matrix.

Office 365 isn't regular desktop office in a VM, but I can't say anything useful about exactly what they're doing without inside information on their architecture.

EDIT: As you're asking about reaosns to use a VM. There are many, a partial list is: You might use it to run an application for a different OS, for testing an environment, for building an app for a different archectiure, to multi-box video games (play several at once), to isolate suspect applications, and to hire out to others who want a "machine" in the cloud.

 

[DaveC426913]

DaveC426913, just for curiosity, your VM is a cloud machine. Is it for work? Why do you have it?
I am currently not interested in a cloud VM but, to start, on creating a VM on my own Windows pc to use Linux...

Not sure if it's cloud, really.

It's run from the hospital (where I go two days a month to work).
I tunnel into the hospital network from my personal lappie (which is not secure) via a VPN, so that I can work securely as if I'm sitting at my desk in the office environment. But there's no physical machine, just a virtual one that's created when I tunnel in.

Naturally, when dealing with confidential patient data, and doctors' finances, the security is essential.