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In my blog, I delve into the world of programming web technologies, Linux, Unix-like, and graphic design using free tools on Linux.

Wednesday, July 31, 2024

QEMU – quick emulator

QEMU (Quick Emulator) is an open source virtualization tool that allows you to run operating systems and programs designed for one machine architecture on another. It provides hardware emulation for various computer systems, including x86, ARM, PowerPC and others. QEMU can be used as a full-system emulator, which means it emulates the entire hardware environment of the target system, or as a user-space emulator, which allows running individual applications compiled for a different architecture. In short something like Virtualbox only without the things we don't like about Oracle.

Key features

Key Feature	Description
Hardware Virtualization	QEMU supports hardware virtualization using KVM (Kernel-based Virtual Machine) on Linux and Hyper-V on Windows, allowing for efficient and high-performance virtual machine execution.
Cross-Platform Compatibility	QEMU can emulate a wide range of hardware architectures, including x86, ARM, MIPS, PowerPC, and more, making it a versatile tool for cross-platform development and testing.
Emulation of Peripherals	QEMU can emulate a variety of hardware peripherals, such as network cards, storage devices, and input devices, allowing for the creation of complex virtual environments.
Live Migration	QEMU supports live migration, which allows you to move a running virtual machine from one host to another with minimal downtime, making it useful for load balancing and high availability scenarios.
Snapshot and Rollback	QEMU provides the ability to take snapshots of virtual machines, which can be used to restore the system to a previous state, making it useful for testing and debugging purposes.
Networking Support	QEMU supports various networking modes, including user-mode networking, tap networking, and bridge networking, allowing for the creation of complex virtual network topologies.
Storage Management	QEMU supports a wide range of storage formats, including raw disk images, QCOW2, and VHD, and provides tools for managing and manipulating these images.

Quick installation

Here are the terminal commands with which we can install everything without reading the explanation:

Installation with explanations

First of all, we need to update the system:

sudo apt update && upgrade

The "build-essential" package in Ubuntu is a metapackage that includes a set of essential tools and libraries needed to compile software from source code. When you install the “build-essential” package, it installs several packages that are typically required during software development. We need this to compile…

sudo apt-get install build-essential git python3-venv flex bison libcairo2-dev libpango1.0-dev libjpeg-dev libgif-dev librsvg2-dev

When used together, QEMU and KVM form a powerful combination known as QEMU-KVM or simply KVM. QEMU provides an emulation and virtualization framework, while KVM uses hardware virtualization extensions (such as Intel VT-x or AMD-V) to improve performance and efficiency. With QEMU-KVM, you can create and manage virtual machines running guest operating systems, such as Linux, Windows, or other supported operating systems. Virtual machines have access to virtualized hardware resources, including CPU cores, memory, storage devices, and network interfaces.

sudo apt install qemu-kvm 

Virt-manager is a graphical user interface (GUI) application for managing virtual machines (VMs) and virtualization hosts. It is built on the libvirt API, which is a library for interacting with various virtualization technologies, including QEMU-KVM, Xen, LXC, and others.

sudo apt install virt-manager

libvirt-daemon, or simply libvirtd, is a component of the libvirt library and tools. It acts as a back-end service that manages virtualization capabilities and provides an API to interact with various virtualization technologies, such as QEMU-KVM, Xen, LXC, and others. libvirt-daemon provides a common interface and abstraction layer for managing virtual machines and hypervisors. It allows applications and tools to control and monitor virtualization hosts, perform virtual machine management tasks, and access virtualization resources.

sudo apt install libvirt-daemon

Let's provide services:

sudo systemctl enable libvirtd
sudo systemctl start libvirtd

Then we will compile the components that cannot be distributed in "binary" form:

cd ~/Downloads/
git clone https://gitlab.com/qemu-project/qemu.git
cd qemu
git submodule init
git submodule update --recursive
./configure
make
sudo make install

Testing with Alpine Linux

Alpine Linux is a lightweight Linux distribution focused on security and highly efficient. It is designed with simplicity, resource efficiency and security in mind, making it particularly suitable for embedded systems, container environments and thin servers. First, we will look for the ISO file, then enter in the search engine:

alpine linux download

Then we download the EXTENDED x86_64 ISO version. After that, we have to create a virtual disk, and we do that with the command:

qemu-img create -f qcow2 alpine.qcow2 8G

And the command with which we start our virtual computer is:

qemu-system-x86_64 -m 512 -boot d -cdrom ./alpine-extended-3.18.2-x86_64.iso -hda alpine.qcow2 -display sdl -enable-kvm

posted by damirs @ July 31, 2024