OpenStack Summit October 2015 Tokyo

Networking for container is rapidly evolving and overlay network is emerging as a popular choice given its simplicity.  One example is Flannel, a generic overlay network using IP datagrams on top of UDP.  Once deployed on a specific underlying infrastructure such as Neutron, there may be opportunities to optimize for performance and to ease some of the limitation of the overlay network.  In this talk, we look at the particular case of a Kubernetes cluster with Flannel running on Neutron networking and VM or baremetal.  This cluster would be provisioned by Magnum.

We will show how Flannel works with Neutron and Kubernetes' internal routing by tracing a round trip message.  We will quantify the overhead of Flannel and identify potential performance optimization.  We will look at the limitation of Flannel from the container perspective and show how some can be mitigated by Neutron.  We will show a demo for these features in a POC based on Magnum and Neutron.  Finally, we will discuss how the POC can be generalized to apply to other overlay  networks.