kubespray/inventory/sample/group_vars/k8s_cluster/k8s-net-flannel.yml

# see roles/network_plugin/flannel/defaults/main.yml

## interface that should be used for flannel operations
## This is actually an inventory cluster-level item
# flannel_interface:

## Select interface that should be used for flannel operations by regexp on Name or IP
## This is actually an inventory cluster-level item
## example: select interface with ip from net 10.0.0.0/23
## single quote and escape backslashes
# flannel_interface_regexp: '10\\.0\\.[0-2]\\.\\d{1,3}'

# You can choose what type of flannel backend to use: 'vxlan',  'host-gw' or 'wireguard'
# please refer to flannel's docs : https://github.com/coreos/flannel/blob/master/README.md
# flannel_backend_type: "vxlan"
# flannel_vxlan_vni: 1
# flannel_vxlan_port: 8472
# flannel_vxlan_direct_routing: false