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.