anyone use fbtracert successfully?

Wed Nov 24 17:49:12 UTC 2021

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 at gmail.com

On Wed, Nov 24, 2021 at 12:47 PM Thomas Scott <mr.thomas.scott at 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 at gmail.com
>
>
> On Wed, Nov 24, 2021 at 12:23 PM Adam Thompson <athompson at 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 at merlin.mb.ca
>> www.merlin.mb.ca
>>
>>
>>
>
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