flannel 0.9.1~ds1-1 (armhf binary) in ubuntu bionic

 Flannel is a virtual network that gives a subnet to each host for
 use with container runtimes.
 .
 Platforms like Google's Kubernetes assume that each container (pod)
 has a unique, routable IP inside the cluster. The advantage of this
 model is that it reduces the complexity of doing port mapping.