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Configuring Libvirt

Now that we've got the packages installed, you might notice that when you try to open virt-manager, it asks for the root password. To smooth things out, we'll need to configuring libvirt, qemu, and virt-manager for adjust permissions so everything runs more seamlessly.

Adjust Permissions for virt-manager​

Here’s how to set up your system so you can use virt-manager without constantly needing root access:

  1. Open the configuration file with:

    sudo vim /etc/libvirt/libvirtd.conf

  2. Look for the unix_sock_group and unix_sock_rw_perms entries in the file. Uncomment these lines and set the values as shown below:

    • Set unix_sock_group to libvirt:

      unix_sock_group = "libvirt"

    • Set unix_sock_rw_perms to 0770 to allow the right permissions for virt-manager:

      unix_sock_rw_perms = "0770"

  3. Save and exit by typing :wq.

This configuration will let you launch and manage virt-manager without running into permission problems.

If you run into issues with virt-manager, having logs can be a lifesaver. To set up logging:

  1. Open the /etc/libvirt/libvirtd.conf file again:

    sudo vim /etc/libvirt/libvirtd.conf

  2. Add these lines at the end of the file to set up logging:

    log_filters="3:qemu 1:libvirt"
    log_outputs="2:file:/var/log/libvirt/libvirtd.log"

This way, you’ll have detailed logs to help troubleshoot any problems.

Add Your User to the libvirt Group​

To use virt-manager without any superuser warnings, add your user to the libvirt and kvm groups:

  1. Run the following command: 
    sudo usermod -a -G kvm,libvirt $(whoami)

Enable and Start Libvirt Services​

Make sure libvirt services start automatically on boot and then start the libvirt service:

sudo systemctl enable libvirtd
sudo systemctl start libvirtd

Verify Group Membership​

Check that your user has been added to the necessary groups:

sudo groups $(whoami)

This confirms that you’ve successfully added your user to the libvirt and kvm groups.

QEMU Configuration​

To make sure QEMU processes run with your user permissions:

  1. Edit the qemu.conf file:

    sudo vim /etc/libvirt/qemu.conf

    Tip: In vim, you can quickly find user = by pressing /, typing user =, and pressing Enter.

  2. Look for these lines:

    user = "libvirt"
    group = "libvirt"

  3. Change "libvirt" to your username:

    user = "username"
    group = "username"

This adjustment ensures QEMU processes run with your user privileges.

Restart the libvirtd Service​

Apply your changes by restarting the libvirtd service:

sudo systemctl restart libvirtd

Start virsh Network Automatically - (Optional but Recommended)​

If you only want to passthrough your LAN or wireless, ignore it's ok.

Every standard libvirt installation provides NAT based connectivity to virtual machines out of the box. This is the so called default virtual network.

For more: https://wiki.libvirt.org/Networking.html

sudo virsh net-autostart default

Now, you’ve configured permissions, added your user to the right groups, QEMU settings, and ensured services are running correctly.

What’s Next?​

Now it’s time to download the ISO files for the operating systems you’ll be using.