ReStarted box A, as advised.
Opened the Virtual Machine Manager. Boo Hoo!
It says “Could not detect a default hypervisor. Make sure the appropriate QEMU/KVM virtualization and libvirt packages are installed to manage virtualization on this host.
A virtualization connection can be manually added via File->Add Connection”
Did you not receive an error message about qemu-kvm?
sudo apt install qemu-kvm
Package qemu-kvm is a virtual package provided by:
qemu-system-x86-hwe 1:10.2.1+ds-1ubuntu4.2 (= 1:10.2.1+ds-1ubuntu4.2)
qemu-system-x86 1:10.2.1+ds-1ubuntu3.1 (= 1:10.2.1+ds-1ubuntu3.1)
You should explicitly select one to install.
Error: Package 'qemu-kvm' has no installation candidate
Try this complete command to install the packages for qemu-kvm
But it will get marked as manually installed that way. virtinst is a dependency of virt-mananger. libvirt-daemon-system is most likely already installed, too, because it’s recommened by the latter, and APT, by default, installs recommended packages as well. In turn, libvirt-clients is a dependency of libvirt-daemon-system.
So make that:
sudo qemu-system-x86 virt-manager bridge-utils
and you’ll have leaner system. It’s always good practice to minimize the number of manually installed packages. Those should be limited to what you actually want; the rest is APT magic.
BTW, QEMU isn’t even a suggestion of virt-manager, because the latter (by means of libvirt) is a generic frontend for most any type of virtualization and can also manage remote machines, IIUC.
virt-manager is already the newest version (1:5.1.0-1).
libvirt-clients is already the newest version (12.0.0-1ubuntu5.1).
libvirt-clients set to manually installed.
Installing:
bridge-utils libvirt-daemon-system qemu-system-x86 virtinst
