New resolvconf interacts badly with something in installs

Bug #926447 reported by Thomas Bushnell, BSG on 2012-02-04
This bug affects 1 person
Affects Status Importance Assigned to Milestone
netcfg (Ubuntu)
Stéphane Graber

Bug Description

As of ubuntu7 (and maybe ubuntu6), we get failing installs related to the new resolvconf changes which do the /etc/resolv.conf link in the postinst.

During the "select and install software" step, we see /etc/resolv.conf go away (simply vanish) at some point in the prep step, and then we get the question about automatic upgrades, and then it goes away again during the install packages step. Then when the resulting error is printed (that it can't find our package source or proxy, because the names don't resolve) it gets put back.

It's really clear what's happening when I have another VT which just does ls -l /etc/resolv.conf in a loop.

Still investigating.

Stéphane Graber (stgraber) wrote :

I can confirm it here so marking as Critical but not marking as Triaged just yet as I'm unsure it's resolvconf's fault.
It may instead be netcfg's or another d-i component touching /etc/resolv.conf

Resolvconf's behavior at install time is:
 - Move current resolv.conf to /run/resolvconf/resolv.conf
 - Make relative symlink from /etc/resolv.conf to ../run/resolvconf/resolv.conf

But the above happens during debootstrap so it's probably not what you see. The rest of resolvconf is either trigger by ifupdown, dhclient, network-manager or init but none of these should be running in the install target (or something else is clearly wrong).

I'll try to spend some time this weekend testing this as it's making some of my automated installs (all of these depending on network) fail, not to mention other people's ;)

Changed in resolvconf (Ubuntu):
importance: Undecided → Critical
assignee: nobody → Stéphane Graber (stgraber)
affects: resolvconf (Ubuntu) → netcfg (Ubuntu)
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package netcfg - 1.68ubuntu9

netcfg (1.68ubuntu9) precise; urgency=low

  * Add a post-base-install hook to detect resolvconf and copy
    /run/resolvconf/resolv.conf to outside the target so that when /run
    is bind-mounted DNS resolving continues to work. (LP: #926447)
  * Apply patch from Alec Warner making netcfg respect netcfg/dhcpv6_timeout
    and running dhclient in one-shot mode (-1). (LP: #917905)
 -- Stephane Graber <email address hidden> Mon, 06 Feb 2012 12:05:02 -0500

Changed in netcfg (Ubuntu):
status: New → Fix Released

I'm pleased to report that with the newly rebuilt installer images that include this patch, the symptoms we reported are no longer visible. Thanks!

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