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Chapter 8: Troubleshooting

8.1 Problem: apt-listbugs reports errors using HTTP proxy

Solution: advise them not to use the main proxy for access to bugs.debian.org, adding some bits like following to /etc/apt/apt.conf:

Acquire::HTTP::Proxy::bugs.debian.org "DIRECT";
//or Acquire::HTTP::Proxy::bugs.debian.org  "other.proxy:port"

Real configurable pass-through for unsupported actions mode will be added in some future version of Apt-Cacher NG.

Thanks to Jamil Djadala for finding this workaround.

8.2 Problem: non-interactive expiration action reproducibly aborts

A quick investigation of action logs should help identifying the problem. A typical one is a mirror listed somewhere which is not reachable when expiration runs.

Unfortunately there is no simple and safe way to solve this. One method is setting the ExAbortOnProblems configuration variable, but this can destroy the whole cache if a bigger problem with index file occurs and this state remains unnoticed for many days until ExTreshold period (see configuration) is over.

Another way is listing the index files of the faulty mirrors to a special file. It needs to be stored as "ignore_list" in the configuration directory and store one path name per line with paths relative to the cache directory, as seen in the error messages.

8.3 Problem: apt-get freezes when downloading files

Solution: First, check:

If nothing helps then you may have hit a spooky problem which is hard to track down. If you like, help the author on problem identification. To do that, do:

  su -
  # enter root password
  cd /tmp
  apt-get source apt-cacher-ng
  apt-get build-dep apt-cacher-ng
  cd apt-cacher-ng-*
  make acng DEBUG=1
  /etc/init.d/apt-cacher-ng stop
  ./apt-cacher-ng -c /etc/apt-cacher-ng logdir=/tmp foreground=1 debug=6
  # (let apt-get run now, on timeouts just wait >> 20 seconds)
  # stop the daemon with Ctrl-C
  /etc/init.d/apt-cacher-ng start
  # compress /tmp/apt-cacher.err and send it to author
  chown -R apt-cacher-ng:apt-cacher-ng /var/cache/apt-cacher-ng

The value of debug can be varied to have different verbosity (see section 7.5 for more information about Debug levels). 11 is recommended for really weird problems.

8.4 apt-get reports corrupted bzip2 data

Symptoms: apt-get fails to run through "update" no matter what you do. And you may have get a message like this one.

99% [6 Packages bzip2 0] [Waiting for headers] [Waiting for headers]
bzip2: Data integrity error when decompressing.
        Input file = (stdin), output file = (stdout)

It is possible that the compressed file(s) have become corrupted.
You can use the -tvv option to test integrity of such files.

You can use the `bzip2recover' program to attempt to recover
data from undamaged sections of corrupted files.

Err http://debian.netcologne.de unstable/main Packages              
  Sub-process bzip2 returned an error code (2)

Comments to blade@debian.org
[Eduard Bloch, Tue, 20 Nov 2007 00:03:24 +0100]