kubespray/roles/docker/templates/create_cbr.j2

#!/bin/bash

# Create calico bridge cbr0 if it doesn't exist
ifaces=$(ifconfig -a | sed 's/[ \t].*//;/^\(lo\|\)$/d' |tr '\n' ' ')
if ! [[ "${ifaces}" =~ "cbr0" ]];then
   brctl addbr cbr0
   ip link set cbr0 up
fi

# Configure calico bridge ip
br_ips=$(ip addr list cbr0 |grep "inet " |cut -d' ' -f6)
if ! [[ "${br_ips}" =~ "{{ br_addr }}/{{ overlay_network_host_prefix }}" ]];then
       ip a add {{ br_addr }}/{{ overlay_network_host_prefix }} dev cbr0
fi