Install KVM/QEMU on Ubuntu 24.04 & Create a VM

KVM (Kernel-based Virtual Machine) turns the Linux kernel into a Type-1 hypervisor, and on Ubuntu 24.04 LTS it is the fastest, most production-proven way to run virtual machines on commodity hardware. It is the same hypervisor that powers OpenStack Nova in large private clouds, so the skills you build here scale directly from a single workstation to a full data centre.

This guide walks through the whole path on Ubuntu 24.04: checking that your CPU supports hardware virtualization, installing the KVM/QEMU and libvirt stack, validating the install, and creating your first VM both from the command line with virt-install and from the graphical virt-manager. Every command is copy-paste ready.

Prerequisites

You need a 64-bit machine running Ubuntu 24.04 LTS with a CPU that supports hardware virtualization (Intel VT-x or AMD-V), a user account with sudo privileges, and a few gigabytes of free disk space for VM images. Virtualization must also be enabled in the BIOS/UEFI — on many machines it ships disabled.

Step 1: Check hardware virtualization support

First confirm the CPU exposes virtualization extensions. A non-zero count means the flags (vmx for Intel, svm for AMD) are present:

egrep -c '(vmx|svm)' /proc/cpuinfo

If this prints 0, reboot into your BIOS/UEFI and enable Intel VT-x or AMD-V (SVM). The cleanest validation tool is kvm-ok, shipped in the cpu-checker package:

sudo apt update
sudo apt install -y cpu-checker
sudo kvm-ok

A healthy system reports:

INFO: /dev/kvm exists
KVM acceleration can be used

Step 2: Install the KVM/QEMU stack

Install QEMU/KVM, libvirt (the management daemon), the network bridge helper, and the tooling for creating and managing VMs:

sudo apt update
sudo apt install -y qemu-kvm libvirt-daemon-system libvirt-clients \
  bridge-utils virtinst virt-manager

The libvirt-daemon-system package installs and starts the libvirtd service automatically. Confirm it is running:

systemctl status libvirtd --no-pager

Step 3: Add your user to the libvirt and kvm groups

To manage VMs without sudo on every command, add your account to the relevant groups:

sudo usermod -aG libvirt,kvm $USER

Group membership only applies to new login sessions. Either log out and back in, or apply it to the current shell:

newgrp libvirt

Step 4: Verify the installation

The virsh CLI is your main control surface for libvirt. List running VMs (none yet) and verify the default NAT network is active:

virsh list --all
virsh net-list --all

If the default network is not active, start it and set it to autostart so VMs get DHCP and outbound connectivity:

virsh net-start default
virsh net-autostart default

Run a full host capability check; it should report that KVM acceleration is in use rather than slow software emulation:

virt-host-validate qemu

Step 5: Create a VM from the command line with virt-install

The command-line route is ideal for servers and automation. Download an Ubuntu 24.04 cloud or server ISO into the libvirt images directory first:

sudo wget -O /var/lib/libvirt/images/ubuntu-24.04-live-server-amd64.iso \
  https://releases.ubuntu.com/24.04/ubuntu-24.04.2-live-server-amd64.iso

Now provision a VM with 2 vCPUs, 2 GiB RAM, and a 20 GiB qcow2 disk attached to the default NAT network:

virt-install \
  --name ubuntu-test \
  --memory 2048 \
  --vcpus 2 \
  --disk size=20,format=qcow2 \
  --cdrom /var/lib/libvirt/images/ubuntu-24.04-live-server-amd64.iso \
  --os-variant ubuntu24.04 \
  --network network=default \
  --graphics vnc \
  --noautoconsole

If --os-variant ubuntu24.04 is rejected, run osinfo-query os | grep ubuntu to find a supported variant string. The VM now exists and is booting the installer.

Step 6: Create a VM with virt-manager (GUI)

On a desktop, the Virtual Machine Manager offers a friendlier path. Launch it from your menu or with:

virt-manager

Click Create a new virtual machine, choose Local install media, point it at your ISO, allocate CPU/RAM/disk, and finish. virt-manager opens a console so you can step through the OS installer interactively.

Step 7: Manage your new VM

A handful of virsh commands cover daily operation. Start, gracefully shut down, or force off a VM, and have it boot automatically with the host:

virsh start ubuntu-test
virsh shutdown ubuntu-test
virsh destroy ubuntu-test
virsh autostart ubuntu-test

To find a VM's IP address once the guest agent or DHCP lease is up:

virsh domifaddr ubuntu-test

Troubleshooting and common pitfalls

A few issues trip up most newcomers:

• ‘/dev/kvm does not exist’ — virtualization is disabled in BIOS/UEFI, or you are inside a VM without nested virtualization enabled.
• Permission denied on the socket — you have not re-logged in after the usermod step; group membership is not yet active.
• Very slow VMs — KVM acceleration is not engaged and QEMU fell back to TCG emulation. Re-run kvm-ok and virt-host-validate to confirm.
• No network in the guest — the default libvirt network is not started; run the net-start/net-autostart commands above.

Where to go next

Now that the hypervisor is running, the natural next step is driving it from the CLI. Our companion tutorial on libvirt and virsh basics covers snapshots, domain XML editing, and storage pools in depth. To back your VMs with resilient, distributed storage instead of a single local disk, see using Ceph RBD as KVM storage.

Conclusion

You now have a fully working KVM/QEMU hypervisor on Ubuntu 24.04, validated hardware acceleration, and a first VM created two different ways. KVM is exactly the open, license-free foundation that makes it a credible alternative to proprietary platforms — it is the same hypervisor clouditiv runs in production. If you would rather not operate hypervisors, networking, and storage yourself, clouditiv runs a sovereign, ISO 27001 / BSI C5 private cloud on Ubuntu 24.04 + OpenStack 2025.2 with your data staying in Germany. Explore our VMware alternative to see how the same KVM technology scales into a managed cloud.