Hi, I've been trying to migrate some of my CentOS 7 KVM hypervisors to CentOS 8, and I have encountered the following issue while trying to load my network config: virsh:     error: Failed to start network test1     error: internal error: Network is already in use by interface virbr2 journalctl:     error : networkCheckRouteCollision:123 : internal error: Network is already in use by interface virbr2 I use the following network definitions, which are a bit non-standard, however they work perfectly on CentOS 7: <network>   <name>test1</name>   <forward mode='open'/>   <bridge name='virbr1' stp='off' delay='0'/>   <mac address='52:54:00:c1:a7:7c'/>   <dns enable='no'/>   <ip address='10.0.0.1' netmask='255.255.255.255'></ip>   <route address='192.168.1.22' prefix='32' gateway='10.0.0.1'/> </network> <network>   <name>test2</name>   <forward mode='open'/>   <bridge name='virbr2' stp='off' delay='0'/>   <mac address='52:54:00:54:09:3c'/>   <dns enable='no'/>   <ip address='10.0.0.1' netmask='255.255.255.255'></ip>   <route address='192.168.1.33' prefix='32' gateway='10.0.0.1'/> </network> My question is, why is the behaviour different across CentOS releases, despite the libvirt versions apparently matching? Output from both systems is the same: # virsh version Compiled against library: libvirt 4.5.0 Using library: libvirt 4.5.0 Using API: QEMU 4.5.0 Running hypervisor: QEMU 2.12.0 What would be the best approach on patching out this check, so I can continue using my network config? Just to summarize the expected output: - virbr1 and virbr2 get created, each one with an address 10.0.0.1/32. - Two routes get created: 192.168.1.22 via 10.0.0.1 dev virbr1 192.168.1.33 via 10.0.0.1 dev virbr2 Thanks, Filip Hruska