virt-manager always start with a warning message:

Could not detect a default hypervisor. Make sure the appropriate virtualization packages containing kvm, qemu, libvirt, etc. are installed and that libvirtd is running.

So each time I start it I need to manually add a connection which annoy me. To avoid that I would like that it either automatically find an hypervisor or specifying my default hypervisor somewhere; both behavior that virt-manger should do on any distro but that's not the case for NixOS.

I tried the following without any successful results:

• export LIBVIRT_DEFAULT_URI="qemu:///system"
• adding LIBVIRT_DEFAULT_URI="qemu:///system" environment to libvirtd.service
• adding the line uri_default = "qemu:///system" to:
  • /etc/libvirt/libvirt.conf
  • /var/lib/libvirt/libvirt.conf
  • /var/lib/libvirt/libvirtd.conf
  • ~/.config/libvirt/libvirt.conf
  • ~/.config/libvirt/libvirtd.conf

For sure I can start it like this virt-manager --connect qemu:///system but that's only a workaround.