Re: anyone use fbtracert successfully?

[Thomas Scott <mr.thomas.scott () gmail com>]

Ha, my apologies, I thought I was writing this for a Linux User Group, not
a NOG. Ignore my simplistic explanations.
- Thomas Scott | mr.thomas.scott () gmail com


On Wed, Nov 24, 2021 at 12:47 PM Thomas Scott <mr.thomas.scott () gmail com>
wrote:

> I have used it successfully in a test environment that I was using ECMP
> in. Most of the public networks that I've worked with don't use ECMP as
> often as other methods for steering traffic (LAGs, BGP MEDs, etc).
>
> What I have seen it fantastically useful for was troubleshooting a transit
> provider, or for when they were congested or had a flapping core link.
> Granted I *think *it's still subject to ICMP deprioritization (most SP's
> use it prodigiously), and most MPLS cores don't decrement TTL, but it was
> still useful to be able to show them "no, at this IP, I *always* drop
> traffic, when..."
>
> - Thomas Scott | mr.thomas.scott () gmail com
>
>
> On Wed, Nov 24, 2021 at 12:23 PM Adam Thompson <athompson () merlin mb ca>
> wrote:
>
> > The tool fbtracert (http://github.com/facebookarchive/fbtracert) was
> > mentioned here recently as a way to get visibility into multi-pathing.
> >
> > Has anyone here ever used this tool successfully?
> >
> >
> >
> > Supposedly Facebook uses this tool internally, but… that doesn’t help
> > much.
> >
> >
> >
> > I’ve tried it on 4 different platforms/OSes (WSL Ubuntu; RedHat; Debian;
> > OpenBSD), and versions of Go (v1.10 through v1.16), in three very different
> > environments (on-prem public IP; on-prem NAT’d; cloud public IP), and I’ve
> > yet to see it produce any meaningful output – each run/iteration/thread
> > only detects one, single, hop out of the entire chain of routers, making it
> > less than useful.  Granted, that’s not a full regression test by any means,
> > but if anyone here has ever used it successfully, could you please let me
> > know what sort of environment you ran it in/on?
> >
> >
> >
> > Thanks,
> >
> > -Adam
> >
> >
> >
> > *Adam Thompson*
> > Consultant, Infrastructure Services
> > [image: 1593169877849]
> > 100 - 135 Innovation Drive
> > Winnipeg, MB, R3T 6A8
> > (204) 977-6824 or 1-800-430-6404 (MB only)
> > athompson () merlin mb ca
> > www.merlin.mb.ca