Fails to launch recovery menu when (at least) Postfix installed

I think this is a bug in both postfix and friendly-recovery.

- resolvconf will always be run in early boot, to ensure that /etc/resolv.conf is available ASAP - *before* the root filesystem is mounted read-write. Any resolvconf hooks, such as /etc/resolvconf/update-libc.d/postfix, *must* account for this and not exit non-zero if the filesystem is not yet writable. (The hook can and should be a no-op at this point in the boot, because the postfix init script which runs later will do its own copy of /etc/resolv.conf into the chroot.)

- friendly-recovery should not care about the exit status of the initctl emit command. It should still wait for all dependent events to trigger in order to not race, but it should not care if one of the dependent jobs has failed.

So this is a medium-severity bug in friendly-recovery, and a high-severity bug in postfix.

Thomas, is there any chance that you have postfix installed in the environment where you're seeing the resolvconf job fail at boot? If so, this postfix resolvconf hook script probably explains what you're seeing. (And if you don't have postfix installed, it could be a different hook script causing a similar problem.)

This bug was fixed in the package postfix - 2.8.7-1ubuntu1

---------------
postfix (2.8.7-1ubuntu1) precise; urgency=low

  * debian/update-libc.d: before we try to copy the resolv.conf over, just
    check if the service is running by calling /etc/init.d/postfix status.
    If it's not running, there's never a need to copy, and if it's running
    we know the package is installed - making other checks superfluous and
    ensuring our hook doesn't exit non-zero if called before /var is mounted
    read-write. LP: #927803.
 -- Steve Langasek <email address hidden> Thu, 16 Feb 2012 17:53:51 -0800

> Thomas, is there any chance that you have postfix installed
> in the environment where you're seeing the resolvconf job
> fail at boot?

Yes, postfix was installed and was causing the resolvconf job to fail at boot. See https://bugs.launchpad.net/ubuntu/+source/resolvconf/+bug/933566/comments/6.

I installed postfix 2.8.7-1ubuntu1. It still causes the resolvconf job to fail at boot.

    $ status resolvconf
    resolvconf stop/waiting
    $ dpkg -l postfix|grep ^ii
    ii postfix 2.8.7-1ubuntu1 High-performance mail transport agent

/var/log/upstart/resolvconf.log:
    cp: cannot create regular file `/var/spool/postfix/etc/resolv.conf': Read-only file system
    run-parts: /etc/resolvconf/update-libc.d/postfix exited with return code 1
    run-parts: /etc/resolvconf/update.d/libc exited with return code 1

Not quite fixed then, but I've reproduced this and see what's going wrong.

This bug was fixed in the package postfix - 2.8.7-1ubuntu2

---------------
postfix (2.8.7-1ubuntu2) precise; urgency=low

  * debian/init.d: if postmulti fails (which for some reason it does when
    the rootfs is read-only in early boot!), the init script 'status'
    command returns zero because "all" of 0 configured instances are
    running. Fix the script to return non-zero in this case. LP: #927803.
 -- Steve Langasek <email address hidden> Fri, 17 Feb 2012 11:07:48 -0800