At times I have found the need to visualize the network connectivity of KVM instances on a Hypervisor Host. I normally use libvirt and KVM for launching my VM workloads. In this post we will look at a simple script that can parse the information available with libvirt and the host kernel to plot the network connectivity between the KVM instances. The script can parse Linux Bridge and OVS based switches.
It can generate a GraphViz based topology rendering (requires pygraphviz), can use networkx and d3js to produce a webpage which is exposed using a simple webserver or just a json output describing the network graph.
The source of the script is available here .
The following is a sample output of my hypervisor host.
SVG using d3js
PNG using GraphViz