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

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 [email protected].

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.