Kernel-based Virtual Machine (KVM) is a popular virtualization solution for Linux, allowing users to run multiple isolated virtual environments known as virtual machines (VMs) on a single physical server. Ubuntu, with its ease of use and wide support, makes an excellent platform for deploying KVM. This guide will walk you through the process of installing and configuring KVM on Ubuntu, tailored for newcomers to the world of virtualization while providing the technical depth required to get you started.

Prerequisites

Before diving into the installation process, ensure your Ubuntu system meets the following requirements:

• A CPU with virtualization extensions (Intel VT-x or AMD-V).
• At least 4GB of RAM (more is recommended to allocate to VMs).
• Sufficient disk space for the host and anticipated guest VMs.
• Ubuntu 18.04 LTS or later installed.

Step 1: Verifying Virtualization Support

First, you need to verify if your CPU supports hardware virtualization. Open your terminal and enter the following command:

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

If the output is greater than 0, your system supports virtualization. If it’s 0, you may need to enable virtualization in your BIOS settings.

Step 2: Installing KVM and Required Packages

Ubuntu makes it straightforward to install KVM and associated packages. Run the following commands to install KVM, QEMU (the machine emulator that works with KVM), and virt-manager (a graphical interface to manage VMs):

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

This command installs all necessary packages and starts the required services.

Step 3: Adding Your User to the KVM Group

To manage KVM without root privileges, add your user to the libvirt and kvm groups by executing:

sudo usermod -aG libvirt $(whoami)
sudo usermod -aG kvm $(whoami)

Log out and log back in for the group changes to take effect.

Step 4: Verifying the Installation

Check if KVM is correctly installed and running with:

virsh list --all

This command should return an empty list of VMs, indicating that KVM is installed and ready to create virtual machines.

Step 5: Initial Network Configuration

KVM installations typically use a network bridge to allow VMs to communicate with each other and the outside world. To set up a network bridge, install the bridge-utils package as part of Step 2.

Create a new bridge named br0 by editing the /etc/network/interfaces file. You may need to replace eth0 with your network interface name:

sudo nano /etc/network/interfaces

Add the following configuration:

auto br0
iface br0 inet dhcp
    bridge_ports eth0

Restart the networking service to apply the changes:

sudo systemctl restart networking

Real-World Example: Creating Your First VM

With KVM and network configuration set, let’s create a simple VM. First, download an ISO image for the operating system you want to install on the VM. Then, use virt-install to create the VM:

virt-install \
--name=myvm \
--ram=2048 \
--vcpus=2 \
--cdrom=/path/to/your.iso \
--disk size=20,path=/var/lib/libvirt/images/myvm.img \
--network bridge=br0 \
--graphics vnc

Replace /path/to/your.iso with the actual path to your downloaded ISO image and adjust the --ram, --vcpus, and --disk size options as needed.

Shape.host Services

After setting up your KVM on Ubuntu, you might be looking for a reliable hosting platform for your virtualized environment. Shape.host offers Linux SSD VPS services, providing high-performance, scalable, and secure virtual private servers to meet your hosting needs. With Shape.host, you can easily deploy and manage your KVM virtual machines, ensuring optimal performance and uptime for your applications.

By following this guide, you should now have a functional KVM setup on your Ubuntu system, ready to host your virtual machines. Whether you’re setting up a development environment, testing new applications, or running a full-fledged production server, KVM and Ubuntu offer a powerful and flexible platform to meet your virtualization needs.