Transform Ubuntu 24.04 into a Powerful KVM Hypervisor with Web Management

Virtualization is a game-changer, letting you run multiple operating systems on one machine. Perfect for testing, hosting, or DevOps adventures. This guide demonstrates how to set up a KVM hypervisor.

Want to transform Ubuntu 24.04 into a robust hypervisor? This guide bypasses Proxmox's complexities, utilizing KVM for rapid VM deployment and Cockpit for easy browser-based control.

What You'll Accomplish

In this tutorial, you’ll convert an Ubuntu 24.04 or Kubuntu 24.04 system into a KVM hypervisor. You'll configure KVM, QEMU, and libvirt, integrate Cockpit for web-based VM management, and deploy a guest VM for testing.

What You Should Know Before Starting

This guide welcomes virtualization beginners and guides you through the process of turning Ubuntu 24.04 into a KVM hypervisor. You'll need some basic skills:

• Executing terminal commands (e.g., sudo apt install, nano).
• Navigating Linux filesystems (e.g., editing files in /etc).
• Basic networking concepts: network interfaces (e.g., enp4s0, wlp3s0), IP addresses, bridging, and NAT. You'll use tools like ip link or nmcli.

Don't worry if terms like "libvirt" sound unfamiliar. We'll explain everything step-by-step.

What You'll Need

• A computer: Running Ubuntu 24.04 or Kubuntu 24.04. Minimum: 4GB RAM, 20GB storage, CPU with virtualization support (Intel VT-x or AMD-V). The more RAM and storage, the better you can run multiple VMs.
• Internet access: For downloading packages and VM ISOs.
• A web browser: Firefox or Chrome for Cockpit access.
• An ISO image: For your guest VM (e.g., Ubuntu 24.04 Desktop ISO or a Windows ISO).
• Time: Allocate 30–45 minutes, depending on your setup speed.

Why Choose KVM on Ubuntu 24.04?

KVM transforms your Linux kernel into a hypervisor, enabling near-native VM performance. Paired with QEMU and libvirt, it's a streamlined alternative to Proxmox or VMware.

• Performance: Efficient VM execution, perfect for homelabs or dev environments.
• Cost-Effective: Like Ubuntu, KVM is completely free.
• Compatibility: Supports various guest OSs (Linux, Windows, BSD).
• Simplified Management: Cockpit's web UI streamlines VM management, no CLI required.

Understanding the Key Components

• KVM: A Linux kernel module turning your system into a hypervisor, enabling near-native VM performance using CPU virtualization features like Intel VT-x.
• QEMU: Provides virtual hardware (CPU, disk, network) for your VMs, working with KVM for fast execution.
• libvirt: Simplifies VM creation, networking, and storage, offering tools like virsh and APIs for automation.
• Cockpit: A web-based interface for managing VMs, system resources, and networks.

Ubuntu 24.04 offers excellent KVM compatibility. Let’s turn your system into a KVM hypervisor!

Step 1: Verify Virtualization Support

Check if your CPU supports virtualization. Open a terminal and run:

lscpu | grep Virtualization

Look for "VT-x" (Intel) or "AMD-V" (AMD). If present, you're all set! If nothing shows, check your BIOS/UEFI:

1. Reboot and enter BIOS (usually F2, Del, or Esc).
2. Enable "Intel VT-x" or "AMD-V" under CPU settings.
3. Save and reboot.

Step 2: Install KVM and Backend Tools

Install KVM, QEMU, and libvirt, the foundation of your KVM hypervisor:

Update your system:

sudo apt update && sudo apt upgrade -y

Then install the packages:

sudo apt install qemu-kvm libvirt-daemon-system libvirt-clients bridge-utils -y

• qemu-kvm: Emulates hardware for VMs.
• libvirt-daemon-system: Manages VMs.
• libvirt-clients: CLI tools like virsh for management.
• bridge-utils: Facilitates network bridging.

Verify KVM is loaded:

lsmod | grep kvm

You should see "kvm_intel" or "kvm_amd".

Add your user to the libvirt group:

sudo usermod -aG libvirt $USER

Log out and back in to apply changes.

Step 3: Set Up a Network Bridge

VMs need network access, so create a bridge (br0) to connect them to your physical network.

Note: libvirt creates a default bridge called virbr0 for NAT-based networking (IPs like 192.168.122.x). For direct network access (IPs like 192.168.0.x), use br0.

Option 1: NetworkManager (Recommended for Kubuntu/Ubuntu Desktop)

1. Check your network interface:

   ip link
   

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   Example: enp4s0. Replace enp4s0 if yours is different.

2. Find your Ethernet connection name:

   nmcli connection show
   

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   Look for the NAME column where DEVICE is enp4s0. Note this name.

   

3. Create a bridge named br0:

   sudo nmcli connection add type bridge ifname br0 con-name bridge-br0
   

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4. Enslave your interface to the bridge:

   sudo nmcli connection add type ethernet ifname enp4s0 master br0 con-name bridge-slave-enp4s0
   

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5. Disable the old connection:

   sudo nmcli connection down "Wired connection 1"
   sudo nmcli connection delete "Wired connection 1"
   

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   Replace "Wired connection 1" with your connection name.

6. Enable DHCP on the bridge:

   sudo nmcli connection modify bridge-br0 ipv4.method auto
   

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7. Activate the bridge:

   sudo nmcli connection up bridge-br0
   

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8. Verify:

   ip addr show br0
   nmcli connection show
   

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   Ensure br0 is active, enp4s0 is enslaved, and virbr0 is separate. Test internet with ping 8.8.8.8.

9. Define br0 in libvirt:

   Create br0.xml in your home directory:

   nano ~/br0.xml
   

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   Add the following:

   <network>
     <name>br0</name>
     <forward mode='bridge'/>
     <bridge name='br0'/>
   </network>
   

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   Save and exit.

10. Define and start the network:

    sudo virsh net-define ~/br0.xml
    sudo virsh net-start br0
    sudo virsh net-autostart br0
    

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11. Verify network list:

     virsh net-list --all
    

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You can now delete ~/br0.xml.

Option 2: Netplan (For Ubuntu Server or If Preferred)

1. Check your interface:

   ip link
   

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   Example: enp4s0.

2. Edit the Netplan config:

   sudo nano /etc/netplan/01-netcfg.yaml
   

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   Use the following:

   network:
     version: 2
     renderer: networkd
     ethernets:
       enp4s0:
         dhcp4: no
     bridges:
       br0:
         interfaces: [enp4s0]
         dhcp4: yes
   

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   Save and exit.

3. Set strict permissions:

   sudo chmod 600 /etc/netplan/01-netcfg.yaml
   

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4. Apply:

   sudo netplan apply
   

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5. Verify:

   ip addr show br0
   

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   Test the internet with ping 8.8.8.8.

Step 4: Install Cockpit for Web Management

Cockpit provides a web UI to manage VMs.

Install Cockpit and its VM plugin:

sudo apt install cockpit cockpit-machines -y

Start and enable Cockpit:

sudo systemctl enable --now cockpit.socket
systemctl status cockpit.socket

Open your browser and visit:

https://localhost:9090

Or use your server’s IP (e.g., https://192.168.0.100:9090) if remote. Log in with your username and password and ignore the self-signed certificate warning.

Allow Cockpit’s port if using a firewall:

sudo ufw allow 9090

You’ll see Cockpit’s dashboard. Turn on administrative access, then click "Virtual Machines."

Step 5: Create a Guest VM using Cockpit

Download the Ubuntu 24.04 Desktop ISO from ubuntu.com.

In Cockpit, go to "Virtual Machines" and click "Create VM". Here are the specifications needed:

• Name: TestVM
• Installation Source: Browse to your ISO.
• OS: Select "Ubuntu 24.04".
• Storage: Create new qcow2 volume (preferred).
• Storage limit: 20GB (adjust as needed).
• Memory: 4GB (adjust as needed).

Click "Create and Edit". In the advanced dialog, ensure br0 is selected as the network interface source. Finally, click "Install".

Step 6: Run and Test the Guest VM

Your VM is running! Let’s test it:

In Cockpit, under "Virtual Machines," click TestVM to see its console.

Log into the guest Ubuntu using your credentials.

Test networking:

Open a terminal in the VM via Cockpit's console.

Run ip addr to confirm a physical network IP (e.g., 192.168.0.x with br0).

Run ping 8.8.8.8 to confirm internet access.

If the VM boots and connects to your network, your KVM hypervisor is working!

Keep Exploring Your Hypervisor

Try these next steps:

• Add More VMs: Create Windows or other Linux VMs using different ISOs.
• Use virt-manager: Install virt-manager (desktop-based alternative to Cockpit).
• Back Up VMs: Export VM disks with virsh for safety.
• Scale Up: Add storage or RAM for heavier workloads.

Wrapping Up

You’ve built a fast KVM hypervisor on Ubuntu 24.04, complete with Cockpit’s web UI and a running guest VM—a perfect platform for learning, testing, and homelab experimentation.