DEV Community: Konstantin Krivko

Virtual machines on QEMU on Linux

Konstantin Krivko — Thu, 20 Mar 2025 08:44:21 +0000

Just a quick note:
I apologize for the rough draft. Because if I want to write a full article, the article never ends up being finished, or published, or written. And if it is written, it's not. So I will always write the version number of the text (v. 01) at the bottom. And I will supplement it as I have free time from work and worldly affairs.

Let's start:
Once upon a time. I had an old system based on a very strange OS like ALTLinux, it was my first time using KDE, in FreeBSD I only saw the console. But I needed to build a VM cluster. So I gave it a try.
Now I have normal hardware, and I will build a VM cluster in VM. This is fun for me, not as fun as attacking orcs with a shovel in a gas mask.
For this I use:
Base OS: Debian
Packages:

qemu-kvm
qemu-img - VM creation and management tool
edk2-ovmf - UEFI image

Let's take a look at the following VM:

VM on bios
VM on UEFI
VM cluster shared disk

I thought I was going to create the VM and all the environment now, but then I realized I needed to install the software first.

Installing and configuring KVM/QEMU

Install KVM/QEMU and related packages using the commands:

$ sudo apt-get install qemu qemu-system-gui qemu-utils

Create the hard disk image with:

$ qemu-img create debian.img 2G

If you're installing a desktop environment, you'll need more than 2G

(v.00.01)

Virtualization.

Konstantin Krivko — Wed, 19 Feb 2025 12:02:49 +0000

I am not going to write about what a hypervisor is or how virtualization works, there are more than enough texts and descriptions about it on the Internet.
I will try to build a cluster of Linux virtual machines, and I will try to do it in different hypervisors.
So, which hypervisors I plan to use.
QEMU - of course, since I've already started with it, text first on Windows and then on Linux.
XEN
KVM
Proxmox
So, KVM is a kernel based virtual machine and is part of the Linux kernel. In the following articles I will touch on each of the technologies. But first, this article will be about QEMU.

Running a lightweight Linux distribution on old hardware.

Konstantin Krivko — Mon, 17 Feb 2025 09:02:01 +0000

I was drunk on Saturday, on Monday I will need to connect to a conference and learn basic Linux functions because the corporation is moving all OS to Linux.
I had very glitchy hardware, Windows OS would start but other applications would sometimes stop because of errors, I needed Linux on this laptop, I couldn't install it only as a Linux PC because my wife uses it occasionally.

First step. Looking for HyperVisors for Windows. Win 10 has a built-in solution like Hyper-v, but I had Win 7. VMware and VirtualBox were so heavy for this case.
At least I found QEMU/KVM, it seemed like it should work, and it did.
Downloading Qemu from the official site
indows 64-bit:

I took the stable 2024 distribution for the installation. The latest 2024 release is 20241220.exe.

Run and agree to all questions
Next, I download Puppy Linux: https://forum.puppylinux.com/puppy-linux-collection.
I click “download” and choose my preferred distribution. I prefer the Debian based one.

Well, I have short resurse for my hardware then I downloaded 32-bit version of Pupy. Time to run QEMU and run Linux
QEMU which we are have is console tool. Then let's open command prompt and change directory:

Then we need to create a disk image for the new virtual machine where we will install the distribution, the following command:

If you get an error like the one shown on the screen above, we need to run a command prompt as administrator:

So, we are ready to run our OS on this virtual machine:

And then the OS will start up and we can answer the following questions and get started:

Tiny distros that helped me.

Konstantin Krivko — Tue, 11 Feb 2025 11:17:53 +0000

If you have a windows PC and it is very old maybe my recommendation will help you.
Why I needed them and maybe they will be useful to you.

The only 3 distributions I have used are:

Puppy Linux - minimum system requirements: Processor with a clock frequency of at least 300 MHz; RAM not less than 128 MB; 512 MB of free space on a hard disk or USB drive; Video card with support for a screen resolution of at least 1024x768 pixels; CD/DVD drive or USB port for booting the system.
I needed to work, my laptop had 1 GB RAM and 1 GHz processor. But it had a glitch on the motherboard and the Windows OS kept rebooting. Only installing Puppy Linux gave this hardware a new life.
Tiny core - Minimal configuration: Tiny Core needs at least 46 MB of RAM in order to run, and (micro) Core requires at least 28 MB of RAM. The minimum CPU is an i486DX. Recommended configuration: A Pentium II CPU and 128 MB of RAM are recommended for Tiny Core.
Another story I need to install a running virtual machine and Linux on Windows. There is no talking about the latest distributions like Ubuntu. And also about highly loaded VMs. About lightweight VM installation and Puppy next time. Well, only tiny core linux allowed me to work.
bodhi linux -Minimal configuration: 512MB RAM, 5GB hard disk space, and a 500MHz processor. 32-bit processors without PAE capability are supported on the same terms as PAE-enabled ones.
For this distro only compared with puppy and tiny on performance, and if the previous ones wouldn't work, that would be plan B.

Off topic but the first OS I used was Knoppix linux - this distro ran from a CD, it was a temporary PC I borrowed from a friend but I couldn't install my OS on it, it was 2002 and the first distro that could run as a liveCD, on very weak hardware but now it needs 4GB RAM which is not tiny.

Do I need Linux?

Konstantin Krivko — Mon, 10 Feb 2025 07:48:10 +0000

*For clarity. I write because I'm trying to clarify my knowledge, about CS, not just Linux, and trying to write articles.

If you're here, it means you're about to change your life or your job. Maybe just learning something new.
So if you have an Android mobile - you're already using Linux.
If you have a MacBook, you are close to using Linux.

Five reasons for use Linux:

Security - For a long time using Windows, I worried about viruses, antiviruses, what games and programs send reports. But after installing Linux, at least half of my worries are gone.
High stability - When installed, the laptop could run for a long time without rebooting, so did the applications.
Cost effective - I had a very cheap laptop at that time. But even Windows Based didn't work very well. After installing a tiny Linux distribution, I used it for years.
Scalability - Linux works on many platforms, now I use other devices with Linux on board.
Lots of tools - I have many free tools and applications.

Of course, this OS is now part of my job. There are finite reasons why Linux doesn't make sense to use. One reason is if you don't want to change your job, such as administrator or programmer, you shouldn't use it.