Installation guide
If the default network (or any other locally-created network) is unable to start, any virtual
machine configured to use that network for its connectivity will also fail to start, resulting in
this error message:
Virtual network default has not been started
In vest ig at io n
One of the most common reasons for a lib virt virtual network's failure to start is that the
dnsmasq instance required to serve DHCP and DNS requests from clients on that network
has failed to start.
To determine if this is the cause, run vi rsh net-start d efaul t from a root shell to start
the default virtual network.
If this action does not successfully start the virtual network, open
/var/l o g /l i bvi rt/l i bvi rtd . l o g to view the complete error log message.
If a message similar to the following appears, the problem is likely a systemwide dnsmasq
instance that is already listening on lib virt 's bridge, and is preventing lib virt 's own
dnsmasq instance from doing so. The most important parts to note in the error message are
d nsmasq and exi t status 2:
Could not start virtual network default: internal error
Child process (/usr/sbin/dnsmasq --strict-order --bind-interfaces
--pid-file=/var/run/libvirt/network/default.pid --conf-file=
--except-interface lo --listen-address 192.168.122.1
--dhcp-range 192.168.122.2,192.168.122.254
--dhcp-leasefile=/var/lib/libvirt/dnsmasq/default.leases
--dhcp-lease-max=253 --dhcp-no-override) status unexpected: exit
status 2
So lu t io n
If the machine is not using dnsmasq to serve DHCP for the physical network, disable
dnsmasq completely.
If it is necessary to run dnsmasq to serve DHCP for the physical network, edit the
/etc/d nsmasq . co nf file. Add or uncomment the first line, as well as one of the two lines
following that line. Do not add or uncomment all three lines:
bind-interfaces
interface=name_of_physical_interface
listen-address=chosen_IP_address
After making this change and saving the file, restart the systemwide dnsmasq service.
Next, start the default network with the vi rsh net-start d efaul t command.
Start the virtual machines.
B.8. PXE boot (or DHCP) on guest failed
Symp t o m
A guest virtual machine starts successfully, but is then either unable to acquire an IP
address from DHCP or boot using the PXE protocol, or both. There are two common causes
Common libvirt errors and t roublesh oot ing
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