[Resolvconf-devel] Re: NetworkManager: resolvconf

[Thomas Hood]

Hi!

Michael Biebl wrote:
> I'm currently working on integrating NM properly into resolvconf and
> ifupdown (resp. the other way around). Looking at resolvconf it seems
> that if I call dhclient manually,
> /etc/dhcp3/dhclient-enter-hooks.d/resolvconf is called to update
> /etc/resolv.conf. For NM this means, that it simply has to check if
> /sbin/resolvconf exists, and if so, don't touch /etc/resolv.conf.
> Eveything works automatically then.


Right.


> But if I use ifup for an dhcp enabled interface, resolvconf seems to be
> called twice: once by ifupdown:
>  /etc/network/if-up.d/000resolvconf
> and then by dhclient:
>  /etc/dhcp3/dhclient-enter-hooks.d/resolvconf
> Is this observation correct?


Yes.  This allows the user to specify dns-* options (e.g., dns-search) in
/etc/network/interfaces which will be included in addition to information
furnished by dhclient.


> Or does ifup call dhclient with a special
> parameter to not call /etc/dhcp3/dhclient-enter-hooks.d/resolvconf?


No.


> I fear, if I integrate support into NM to call the scripts in
> /etc/network/if-*.d/ , resolvconf will be called twice. Or is this
> absolutely ok, and just a bit a waste of resources?


Calling resolvconf twice is OK.  Not too many resources get wasted: if a
call makes no change to resolvconf's database then resolvconf refrains
from calling update scripts.

-- 
Thomas