Date Tue 23 November 2010 Tags linux

We have quite a lot of computers running Ubuntu/Debian, which means that we use a lot of bandwidth downloading new packages and security updates. In the past I have created local mirrors of some of the Ubuntu packages. However, this is probably just as bandwidth unfriendly and seemed prone to breakage.

Recently I read about approx which is a caching proxy server for Debian and Ubuntu. You change the /etc/apt/sources.list on your computers to point the machine running approx. When a computer on your network downloads or updates a package approx will check to see if the package is in its cache. If the package is cached approx will serve it to the computer requesting it and if the package isn't in the cache it is downloaded and stored there before being served to the computer on your network that requested it. So, if you have a whole bunch of computers on your network doing updates, the majority of those requests will be served from the approx cache. The package is only downloaded once from the Ubuntu servers.

You can also set up Squid to work in a similar way. However, this is more complicated, especially if you are already using Squid as a proxy server on your network.

Installation and Configuration.

Installation is simply a matter of:

sudo apt-get install approx

The configuration file is stored in /etc/approx/approx.conf. The default location of cached packages is /var/cache/approx. Since I have limited space on the drive containing "/", I created a symlink to a drive with more space.

My approx.conf looks like this:

# Main ubuntu packages and security updates.

# ppa

On my workstations I modify /etc/apt/sources.list to look like this:

deb maverick main
deb maverick-updates main
deb maverick universe
deb maverick-backports
main restricted universe multiverse

maverick-security universe

maverick-security multiverse

deb maverick-proposed restricted main multiverse universe

Note that is the address of my server that has approx installed and 9999 is the default port that approx listens for requests.

Some more useful tips:

  • approx comes with daily and weekly cron jobs to stop your cache overflowing.
  • You can use approx-import to import any existing packages that you may have already downloaded. These are usually found in /var/cache/apt/archives.


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