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How to create a virtual machine with virt-install

After installing KVM on your Ubuntu or Debian system, the next step is to create a virtual machine using the virt-install command-line tool. Check existing virtual machines Before creating a new VM, check if there are any existing ones: sudo virsh list --all If no machines exist, the list will be empty. Create a virtual machine with virt-install The virt-install command allows you to specify all the VM’s properties. For example:

Monday, October 13, 2025 | 2 minutes Read
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How to install KVM, QEMU and libvirt on Linux

To install KVM on Ubuntu or Debian, you need to prepare the system with the required packages, verify hardware virtualization support, and authorize users to run virtual machines. Below are the steps to install KVM on Ubuntu 24.04 (Noble Numbat) or recent Debian releases. Step 1: Update the system Before installing KVM, update your package repository information: sudo apt update Step 2: Check virtualization support 2.1 Verify CPU compatibility Check if your CPU supports hardware virtualization:

Monday, October 13, 2025 | 2 minutes Read
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How to validate the KVM host installation

Before creating and running virtual machines with KVM, it’s essential to validate that the host meets the required hardware and software capabilities to ensure optimal performance. This guide describes how to verify system capabilities using tools such as virt-host-validate and virsh. 1. Validating CPU virtualization support KVM requires processors with hardware virtualization extensions: Intel: VT-x AMD: AMD-V To check if your CPU is compatible, run: grep --color -Ew 'svm|vmx|lm' /proc/cpuinfo vmx → Intel CPU with VT-x svm → AMD CPU with AMD-V lm → 64-bit support If your CPU lacks these extensions, only CPU emulation will be available and performance will be significantly reduced.

Monday, October 13, 2025 | 2 minutes Read
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Key components of a virtual machine in KVM

In KVM (Kernel-based Virtual Machine), a virtual machine is composed of several elements that interact to emulate a complete hardware environment. Understanding each component helps you manage, troubleshoot, and optimize your VMs more efficiently. 1. Main components Component Description Virtual CPU (vCPU) Cores assigned from the physical host to the guest. Defined with --vcpus when creating the VM. Memory (RAM) Amount of memory assigned. Configured with --ram or can be hot-adjusted with virsh setmem. Virtual disk Storage file (.qcow2, .raw, etc.) used as the guest disk. Managed with virsh vol-* or virt-manager. Network interface Virtual connection (usually virtio or e1000) attached to a libvirt network (default, br0, etc.). Graphics device / console VNC, SPICE, or text mode (no graphical console). Controllable with --graphics or virsh vncdisplay. Firmware / BIOS / UEFI Defines the boot mode (traditional BIOS or UEFI with OVMF). Additional devices CD-ROM, USB controllers, serial channels, sound interfaces, etc. 2. Essential commands to retrieve VM information Once the VM is created, you can use virsh to inspect and manage all its details.

Monday, October 13, 2025 | 3 minutes Read