libvirt cannot create default network

Question

I can't start the default network for libvirt. I get the error in journalctl:

Jun 06 15:22:43 jenia libvirtd[889326]: Unable to create bridge virbr0: Package not installed

I did installed the packages ebtables, bridge-utils and dnsmasq and restarted libvirtd but the problem persists.

Can someone please tell me what package am I missing? I'm using archlinux.

Thanks

P.S.

And the GUI that I'm using (Virtual Machine Manager) gives me:

Error starting network 'default': Unable to create bridge virbr0: Package not installed

Traceback (most recent call last):
  File "/usr/share/virt-manager/virtManager/asyncjob.py", line 75, in cb_wrapper
    callback(asyncjob, *args, **kwargs)
  File "/usr/share/virt-manager/virtManager/asyncjob.py", line 111, in tmpcb
    callback(*args, **kwargs)
  File "/usr/share/virt-manager/virtManager/object/libvirtobject.py", line 66, in newfn
    ret = fn(self, *args, **kwargs)
  File "/usr/share/virt-manager/virtManager/object/network.py", line 75, in start
    self._backend.create()
  File "/usr/lib/python3.8/site-packages/libvirt.py", line 3174, in create
    if ret == -1: raise libvirtError ('virNetworkCreate() failed', net=self)
libvirt.libvirtError: Unable to create bridge virbr0: Package not installed

Answer 1

That error message comes when libvirt is talking to the kernel I believe. So at a guess, the kernel you have installed is missing the bridge kernel modules. Possibly dmesg might tell you more about what is missing. If this is a custom built kernel, make sure you compiled the bridge support. If this is a distro provided kernel, then look for any extra distro packages related to the kernel.

Answer 2

I ran into same problem. I fixed it by

virsh net-start default

as for some reason virt-manager couldn't start it but virsh can. but make sure to check if you have the default network by using virsh net-list --all