Better handle lxc-net job failing to start (when user doesn't need it)

[Karl Hegbloom]

I'm updating the system. I don't use lxc and don't remember installing it. Sorry, I don't know why it failed to upgrade or install.

ProblemType: Package
DistroRelease: Ubuntu 12.04
Package: lxc (not installed)
ProcVersionSignature: Ubuntu 3.2.0-8001.1~ppa1-generic-tuxonice 3.2.5
Uname: Linux 3.2.0-8001-generic-tuxonice x86_64
ApportVersion: 1.93-0ubuntu1
Architecture: amd64
Date: Fri Feb 17 16:55:59 2012
DuplicateSignature:
 Setting up lxc (0.7.5-3ubuntu27) ...
 start: Job failed to start
 invoke-rc.d: initscript lxc-net, action "start" failed.
 dpkg: error processing lxc (--configure):
  subprocess installed post-installation script returned error exit status 1
ErrorMessage: subprocess installed post-installation script returned error exit status 1
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Alpha amd64 (20110301.7)
SourcePackage: lxc
Title: package lxc (not installed) failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: Upgraded to precise on 2012-01-14 (40 days ago)

[Serge Hallyn (serge-hallyn)]

@Karl,

thanks for reporting this bug. I'm sorry it's causing you trouble.

To give an idea of why this happened, could you show the result of the following commands:

   ifconfig -a
   brctl show
   ps -ef | grep dnsmasq
   dpkg -l | grep dnsmasq
   cat /etc/default/lxc
   sudo stop lxc; sudo start lxc

Hopefully those will give an idea of what went wrong. Then, to get past this error, since you don't actually want lxc, you can try:

 sudo apt-get purge lxc

If that fails, then edit /etc/default/lxc and set USE_LXC_BRIDGE="false". Then do 'sudo apt-get install -f' followed by 'sudo apt-get purge lxc'.

Please let me know (by replying here) if you need any more help or if the above did not work.

[Serge Hallyn (serge-hallyn)]

I will assume you have uninstalled lxc and no longer have a problem. Sorry for the inconvenience.

[xlyz (xlyz)]

hi Serge.

same problem here.

problem seems due to having a bridge already configured.

changed USE_LXC_BRIDGE to false in /etc/default/lxc solved it.

if it's not possible to handle an existing bridge during installation, at least a more verbose error message would help.

[Serge Hallyn (serge-hallyn)]

Thanks, you're right, we should find a way to provide better information about what happened.

[Serge Hallyn (serge-hallyn)]

(Changed priority per guidelines to low since there is a workaround. If we haven't fixed it by UDS, we should discuss there how best to present this information to the user)

[xlyz (xlyz)]

more detailed information on how I installed lxc with a bridge already configured:

# sudo aptitude install lxc

installation will abort (as in the first post)

edit /etc/default/lxc changing USE_LXC_BRIDGE from true to false.

# sudo aptitude remove lxc && sudo aptitude install lxc

that's it.

(don't forget to set the right bridge in /etx/lxc/lxc.conf )

[sammcj (sammcj)]

also present on raring with linux 3.9.0.

[Serge Hallyn (serge-hallyn)]

@sammcj,

The bug really should have been fixed. In the past dnsmasq conflicts were known to cause this, and those are fixed in bug 928524. So I'm not sure what's causing this for you.

Could you please report a new bug using 'ubuntu-bug lxc' so we can try and figure out what happened?

Thanks!