Toward Leaner, Faster ovn-northd, with Leonid Ryzhyk from VMware Research Group

OVS Orbit

Leonid Ryzhyk is a senior researcher in the VMware Research Group. The main theme of his work is applying formal methods to build better operating systems and networks. Before joining VMware, Leonid received his PhD from University of New South Wales and NICTA. Leonid has also worked as a researcher at NICTA, as a postdoc at University of Toronto and at Carnegie Mellon University, and as a researcher at Samsung Research America.

In OVN, the ovn-northd daemon acts as an interface and a translator between OVN's northbound and southbound databases. With the existing implementation, any change in the northbound database causes ovn-northd to do a full recomputation of the complete contents of the southbound database. For a large network, this is slow—it can take multiple seconds of CPU time—regardless of the size of the change in the northbound database. Therefore, even a small change, such as adding or removing a single port or a single VM, can take a relatively long time to be realized in the network.

In this talk, Leonid presents a prototype for a solution to the problem. The solution implements incremental computation using a system called Differential Dataflow, which is based on the Datalog language for database queries. Because Datalog is not a particularly friendly language for developers who are not already accustomed to it, Leonid also layered syntactic sugar over it called FTL, for Flow Template Language, which is inspired by the FLWOR syntax from XQuery.

Some of the talk is easier to follow if you view the slides (PDF).

You can contact Leonid via email at [e-mail].

Leonid previously appeared in OVS Orbit in episode 44 on the Cocoon-2 network programming system. Episode 5, with Teemu Koponen and Yusheng Wang, touched on related concepts with its coverage of the nlog language which is also based on Datalog.

OVS Orbit is produced by Ben Pfaff. The intro music in this episode is Drive, featuring cdk and DarrylJ, copyright 2013, 2016 by Alex. The bumper music is Yeah Ant featuring Wired Ant and Javolenus, copyright 2013 by Speck. The outro music is Space Bazooka featuring Doxen Zsigmond, copyright 2013 by Kirkoid. All content is licensed under a Creative Commons Attribution 3.0 Unported (CC BY 3.0) license.