NetworkworkManger and network based filesystem /usr

[Hans de Goede]

Bill Nottingham wrote:
> Hans de Goede (j.w.r.degoede at hhs.nl) said: 
>> Thats a cool trick, can we teach NM to start iscsi too and do that (and 
>> let it complete) before it starts netfs?
> 
> I'm not sure why we couldn't off the top of my head.
> 
>> That would be nicer then my current dbus-send get NM status and sleep 
>> while not connected loop in bash.
>>
>> Although I wonder if this (delaying netfs start until NM is done) is a 
>> good solution, what if some later service which needs one of the dirs 
>> mounted by netfs gets started before NM is done configuring the 
>> interfaces?
> 
> What happens to that service if the network cable happens to be down
> during boot? Services, in general, need to be smarter. If absolutely
> necessary, they can set NETWORKWAIT in /etc/sysconfig/network.
> 

I agree, but the chances of a network cable being non functional in some 
datacenter using iscsi is small, the chances of getting caught by the race 
condition I described are probably bigger. Note as said I agree with you, but 
at the same time I try to play devils advocate here. If we are going to make a 
list of (crazy) unsupported configurations, I'm all for it, but we do need 
write really good release notes for this then.

Then again I think F-9 has this bug too as that defaults to NM too, and I don't 
know how much bugs regarding this we've gotten.

>>> Having network /usr and non-network  / isn't really practical long term.
>>> I'm all for not supporting it.
>> What about having both network based, but not the same fs, so say 2 
>> separate nfs exports one for / and one for /usr, that situation will run 
>> into similar problems, initrd will do some hackish setup of the network 
>> to get the rootfs, but won't mount other network based fs and netfs will 
>> not run untill NM is done, so we once more have a catch 22.
> 
> It's just not a practical setup, IMO.
> 

Agreed, but again I'm playing devils advocate.

Anyways there seems to be some consensus that having /usr seperate from / is a 
somewhat archaic usecase we which we do not necessarily want to support. So for 
now I'll go and write patches for delay iscsi start when using NetworkManager, 
just like netfs currently is started delayed.

Regards,

Hans