Set up KVM && Cockpit WEB Console on Debian Bullseye (11)

UPDATE 08/31/21

In case setting up Debian 11 with KDE you would have manually select "Remote Viewer'  from drop-down menu inside Cockpit Console. It won't be detected automatically like in Debian 11 with Gnome desktop

END UPDATE

UPDATE as of 08/29/21

After kernel upgrade up to 5.13-trunk-amd64 . KVM Hypervisor seems to keep working stable. See How to Install Backports & Experimental Repository on Debian 11

END UPDATE

The presence of Web Cockpit Console is a nice way to manage KVM guest's deployment via clicking the button "Remote Virt-viewer"  built into Cockpit Web Console. Bridge attached to external network interface was also created pretty smoothly utilizing network management section inside Web Console. However, it doesn't look to me as a reason to deprecate virt-manager . Virt-manager still provides a way to edit guest definitions which can be very handy and  sometimes seems to be more flexible versus Cockpit Web console in my very personal opinion.

 Install KVM

 $ sudo apt install qemu-kvm  libvirt-daemon bridge-utils \
         virtinst libvirt-daemon-system -y
 $ sudo apt install  libguestfs-tools libosinfo-bin \
       qemu-system virt-manager -y
 $  sudo modprobe vhost_net 
 $  lsmod | grep vhost
 $  echo vhost_net | sudo tee -a /etc/modules

 $  sudo usermod -a -G libvirt  $(whoami)

 $  sudo reboot

 Install Web Cockpit Console

 $  sudo apt install install cockpit cockpit-machines
 $  sudo apt install cockpit cockpit-machines
 $  sudo systemctl start cockpit.socket
 $  sudo systemctl enable cockpit.socket

 Tuning firewall
 $  sudo apt install firewalld
 $  sudo firewall-cmd --add-service=cockpit --permanent
 $  sudo firewall-cmd --reload