Docker is installed as part of the Kubespray process. By default, 172.17.0.0/16 is reserved for docker. If that conflicts with your local network, then designate another network for docker. One way to do this is to create a file called /etc/docker/daemon.json on each cluster node before beginning the Kubespray process. The following is an example file designating 107.0.0.0/8 for docker: