On Ubuntu, run
sudo apt install qemu-kvm libvirt-daemon-system libvirt-clients bridge-utils
For details, see Ubuntu help page.
On Fedora, run
sudo dnf -y install bridge-utils libvirt virt-install qemu-kvm
and
sudo dnf -y install libvirt-devel virt-top libguestfs-tools guestfs-tools
After that, enable and start the libvirtd service
```
sudo systemctl start libvirtd
sudo systemctl enable libvirtd
```
For details, see Getting started with virtualization (libvirt).