net.add_addr_allfibs=1 behaviour deprecation

[Grzegorz Junka]

On 18/08/2020 19:27, Alexander V. Chernikov wrote:
> 18.08.2020, 09:17, "Grzegorz Junka" <list1 at gjunka.com>:
>> On 18/08/2020 07:54, Julian Elischer wrote:
>>>>
>>>>   No objections has been received.
>>>>   Next steps:
>>>>   * Switch net.add_addr_allfibs to 0 (
>>>>   https://reviews.freebsd.org/D26076 )
>>>>   * Provide an ability to use nexthops from different fibs
>>>>   * Remove net.add_addr_allfibs
>>>>>   Timeline:
>>>>>   Aug 1: summarising feedback and the usecases, decision on proceeding
>>>>>   further
>>>>>   Aug 20 (tentative):  patches for supported usecases
>>>>>   Sep 15 (tentative):  net.add_addr_allfibs removal.
>>>>>
>>>>>   [1]: [base Contents of
>>>>>   /head/sys/net/route.c](https://svnweb.freebsd.org/base/head/sys/net/route.c?revision=178888&view=markup)
>>>>>   [2]: [base Diff of
>>>>>   /head/sys/net/route.c](https://svnweb.freebsd.org/base/head/sys/net/route.c?r1=180839&r2=180840&)
>>>>>
>>>>>   /Alexander
>> Agree completely, defaulting "add_addr_allfibs" to 1 broke many existing
>> installations, which goes against the least surprise principle so many
>> times advocated on FreeBSD lists.
>>
>> This is just one example:
>> https://forums.freebsd.org/threads/strange-behavior-of-setfib-since-freebsd-12-0.73348/
>>
>> Now, changing the default again might again break existing
>> installations, which shouldn't be a reason for not doing it, but might
>> be a reason to better communicate it this time around.
> I plan to communicate it the following way:
> 1) this thread
> 2) GONE_IN13 in the sysctl (which will print console message when set to 1)
> 3) Release notes
> Do you think there are other communication channels one should try to use?


When I was looking for information about why the routing doesn't work as 
expected I didn't know about this settings but couldn't find anything 
relevant in the Handbook, so would really love to see this somehow 
mentioned and explained how to use it in the Handbook if possible.

Thanks

GrzegorzJ