No lo interface after debootstrap install

[Evan Klitzke]

I just did a debootstrap install of Ubuntu 7.04, and had mysterious networking problems. It turns out that the loopback interface was not being started. I looked at /etc/network/interfaces and lo and behold, the lo interface was not set to auto (sorry, couldn't resist the pun). This will cause server-like applications that try to bind to a port on localhost to fail, which can be fairly mystifying...

[Evan Klitzke (eklitzke2)]

It turns out that this was just a configuration item that I missed when I read the debootstrap installation guide. In the guide they do, in fact, warn you to edit /etc/network/interfaces and add a line for the loopback device.

OTOH it seems like this file, and a few other files, could be improved for debootstrap. I think it would be preferable to have a /etc/network/interfaces file that had the loopback device autostart by default, with perhaps commented out entries for other devices. Likewise, the /etc/fstab file is blank in the default configuration, whereas it ought to at least have entries for /proc and /sys, and perhaps commented out entries showing how other lines might look. I would be interested in making some of these changes myself and submitting patches to the package maintainers if someone can help me figure out what I need to do to get started.

[Evan Klitzke (eklitzke2)]

It's me again. I created some patches for the gutsy debootstrap ruleset. The first patch is really small and just fixes a couple of formatting inconsistincies in the ruleset (two instances of hard tabs instead of spaces, and deprecated usage of chown user.group rather than chown user:group). The second patch makes it so that skeleton /etc/fstab, /etc/network/interfaces, and /etc/hosts files are generated.

I'm kind of new to patch, so I'm not sure if I did this right, but the formatting patch is meant to be applied first, followed by the patch that adds the skeleton files. Let me know if I did this incorrectly.

[Evan Klitzke (eklitzke2)]

This is the patch that adds the "skeleton" files.

[Adam Niedling (krychek)]

Is this still an issue?

[Colin Watson (cjwatson)]

This is still valid (of course; Adam didn't even check ...) but I want to think about the installation-guide and code-duplication implications.

[Colin Watson (cjwatson)]

Regarding the first patch: I'm not going to apply the tab/space changes because we like it the way it is. I applied the chown change a while ago, in debootstrap 1.0.9:

  * Use 'chown 0:0' in all scripts rather than deprecated 'chown 0.0'
    (thanks, Evan Klitzke).

[Colin Watson (cjwatson)]

The part of this bug applying to /etc/network/interfaces is fixed thanks to this change, which I think is a fundamentally better approach even though it doesn't deal with releases earlier than lucid:

ifupdown (0.6.8ubuntu29) lucid; urgency=low

  * debian/postinst: if the loopback interface is missing from the config in
    /etc/network/interfaces, add it on upgrade; there is no valid use case
    for a system without localhost, and not bringing this up will cause
    upstart runlevel handling to fail. LP: #497299.

 -- Steve Langasek <email address hidden> Fri, 19 Feb 2010 20:29:32 -0800

(It's always best to keep logic regarding packages' configuration files in those packages rather than in debootstrap.)

I'm not yet sure what to do about /etc/fstab and /etc/hosts. I've confirmed at least that the proposed changes there wouldn't break the installer. The proposed /etc/hosts is probably OK. Aesthetically I feel that the proposed /etc/fstab is probably too verbose and that more documentation should be local and delegated to manual page references or whatever. In any case, though, I strongly believe that Debian and Ubuntu should behave in a semantically identical way here lest sysadmins' heads explode in confusion, so I'll forward the essence of this to Debian.

[Ken Sharp (kennybobs)]

ifupdown isn't even installed in modern chroots, so this is still the case, but then it's a chroot so it's a reasonable case.

Can this be closed now?