Skip site navigation (1)Skip section navigation (2)
Date:      Thu, 26 Mar 2020 15:49:42 +0000
From:      Arthur Chance <freebsd@qeng-ho.org>
To:        Victor Sudakov <vas@sibptus.ru>, "Bjoern A. Zeeb" <bzeeb-lists@lists.zabbadoz.net>
Cc:        freebsd-net@freebsd.org, Miroslav Lachman <000.fbsd@quip.cz>, freebsd-questions@freebsd.org
Subject:   Re: IPv6 in jails
Message-ID:  <df00d98d-ae81-9d8d-78dd-7a403904a921@qeng-ho.org>
In-Reply-To: <20200319140132.GA93947@admin.sibptus.ru>
References:  <20200318151556.GA64871@admin.sibptus.ru> <2dd539ed-0ee3-079b-27b2-28126056c69a@quip.cz> <20200318155046.GD65497@admin.sibptus.ru> <4CA69535-0F6C-40FC-83CF-5000FD728C2D@lists.zabbadoz.net> <20200319021432.GA80800@admin.sibptus.ru> <01EF7656-4F8A-4075-A0B4-27E8AB17B516@lists.zabbadoz.net> <20200319140132.GA93947@admin.sibptus.ru>

next in thread | previous in thread | raw e-mail | index | archive | help
On 19/03/2020 14:01, Victor Sudakov wrote:
> Bjoern A. Zeeb wrote:
>>
>>>> If it does, can you add a
>>>>
>>>> 	exec.start += "sleep  2 ";
>>>>
>>>> to your config
>>>
>>> OK, I've added it to the configs of 3 experimental jails.
>>>
>>>> and see if your problem goes away?
>>>
>>> It goes away partially (only for sshd in 2 of the 3 available jails),
>>> and
>>> not for syslogd in any of the 3 available jails. Restarting the daemons
>>> from within the jail fixes the problem. An example from a problem jail:
>>>
>> ..
>>>
>>>> If it does, the reason is
>>>> that you configure an IPv6 address to an interface and DUD has not
>>>> yet
>>>> completed by the time sshd or other daemons start.  Giving it the 2
> 
> What is "DUD" BTW?
> 

I suspect it's a typo for DAD - duplicate address detection which is
part of IPv6.

>>>> seconds
>>>> avoids this problem and the address is usable at that time.
>>>
>>> There is obviously a race somewhere, but the 2 second sleep does not
>>> eliminate it entirely.
>>
>> Well not so much of a race but than a “gap”.
>>
>> The point is you are configuring an address on the base system and the jail
>> knows nothing about it so it’ll simply start the daemons.  Normally the
>> startup scripts would do the right thing.
>>
>> I don’t think “polluting” jail(8) with logic to check that the addresses
>> become available or not is a good idea.  However I agree that it should
>> automatically do the right thing somehow ..
>>
>>
>>
>>> Thank you for the hint in the right direction, what would you suggest
>>> further?
>>
>> If you make it 3 seconds, does it deterministically work then?
> 
> Not quite: https://termbin.com/arvb
> syslogd sometimes remains deprived of the IPv6 address.
> 


-- 
Violets are red
And roses are blue
When metamaterials
Alter their hue.



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?df00d98d-ae81-9d8d-78dd-7a403904a921>