On Thu, Mar 14, 2019 at 04:55:56PM +0100, Daniel Alvarez Sanchez wrote: > Hi folks, > > Lately I'm getting the question in the subject line more and more > frequently and facing it myself, especially in the context of > OpenStack. > > The shift to OVN in OpenStack involves a totally different approach > when it comes to tracing packet drops. Before OVN, there were a bunch > of network namespaces and devices where you could hook a tcpdump on > and inspect the traffic. People are used to those troubleshooting > techniques and OVS was merely used for normal action switches. > > It's clear that there's tools and techniques to analyze this (trace > tool, port mirroring, etc.), but often times requires quite high > knowledge and understanding of the pipeline and OVS itself to > effectively trace where a packet got dropped. Furthermore, there could > be some scenarios where the packet can be silently dropped. > > I came across this patch [0] and presentation about it [1] which aims > to tackle partly the problem described here (focusing in the DPDK > datapath). > > The intent of this email is to gather some feedback as how to provide > efficient tools and techniques to troubleshoot OVS/OVN issues and what > do you think is immediately missing in this context.
I guess that there are multiple things to do here: - Better document the tools that are available. - Implement improvements, especially UX-wise, to the existing tools. - Identify gaps in the available tools (and then fill them). Do you have any good anecdotes about user/admin frustration? They might be helpful for figuring out how to help. A lot of us here designed and built this stuff and so the gaps are not always obvious to us. _______________________________________________ discuss mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
