OpenStack Summit November 2014 Paris

Randy Bias and Bill Baker first illustrated the parallel of cloud applications to "pets and cattle”, by setting the primitives for scale-out and applications that can tolerate failure. For the cloud applications, (ie cattle), an often forgotten aspect though is the "herding dogs", or simply the control plane that will manage the lifecycle of the cloud and the applications. And as in every cattle, the herding dogs are critical for the survival of the cattle, so is the control plane in a scale out cloud. In this talk will focus specifically on the network control plane and outline the key requirements in terms of performance, reliability, and scale. We will then focus specifically on OpenStack Neutron and present some examples of functions that result in asymptotically quadratic operations that significantly limit scalability. We will present alternative implementations based on SDN controllers that remove these bottlenecks from the Neutron server, and enable the seamless scale of OpenStack clouds.