What is a" virtual machine image " and what does it include?
I understand this is a copy of the OS disk? And another question. For example, I created a virtual machine using an existing image. Then I put a couple of my programs on it, put the firewood on the vidyukha. After that, I created my own image from this machine. And now, if I create a new virtual machine using the created image(with firewood and installed programs) , then the new virtual machine will be an exact copy of the previous one? Will the firewood work?
2 answers
Well, that's about it.
In fact, an image is usually an archive with the data of a virtual machine at some point in time. These are its characteristics, how much memory, processor, which disk, etc., and a copy of the disk with the data available at the time of creating the image (snapshot).
If you do something inside a VM, and then save its image in some format, then yes, the modified data will already be inside this new image. And when you lift from this image, you will get an identical one a copy of the virtual machine. But whether the driver or some software inside will work is of course a question. Because the virtual machine can and will be an exact copy, but the external environment (that is, the host where the hypervisor is raised) may differ. And then some of it can affect.
Sometimes use the concept of "snapshot", "snapshot", it is similar to the image, is a slice of the state of the virtual machine. It is usually stored inside an already working VM and is used to quickly switch between these two states.
In some cases, the image may not be as simple as a regular archive. For example, in Docker-type koteinization systems, such an image is obtained as a layer cake, each layer contains one specific state. And when you create another image based on one image, all the same layers are simply used, only new ones are created. Something like that.
What is a "virtual machine image"? - A virtual machine ( VM or VM) is a virtual computer that uses the allocated resources of a real computer (processor, disk, adapter). A VM image is a computer file that you upload to the station to get a Virtual Machine.
I understand this is a copy of the OS disk? - not only not. This is the machine image, settings device memory....
If I create a new VM using the created one image (with firewood and installed programs) then the new virtual machine will be an exact copy of the previous one? - this is the plan. See below for what it's for in general.
Will the firewood work? - ideally, they should. But not to say that it is always without problems.
But you must upload the image to the station, the version and others that are compatible.
There's a clipping from here
What is a virtual machine for?:
To expand two or more independent operating systems on the same physical device. For example, if you have Windows 7 operating system installed on your computer, and you have installed it on a virtual machine Windows XP / 8 / 10 or Linux;
For experimenting with software (for example, code designed to run on different operating systems) without compromising the stability of the computer;
To install and test various programs and utilities without taking up space on the main PC;
To run programs that the main OS does not support, or to connect hardware that is incompatible with it. For example, apply Windows-programs on Mac or Linux;
To safely launch an application (program) that causes distrust or suspicion of viruses;
To emulate computer networks and complex environments without having to configure a VM every time. You can save the settings and continue with the stage where you left off; to create OS backups.