+<p>The last time I had failing disks, I added the serial number on
+labels I printed and stuck on the short sides of each disk, to be able
+to figure out which disk to take out of the box without having to
+remove each disk to look at the physical vendor label. The vendor
+label is at the top of the disk, which is hidden when the disks are
+mounted inside my box.</p>
+
+<p>I really wish the check_linux_raid Nagios plugin for checking Linux
+Software RAID in the
+<a href="http://packages.qa.debian.org/n/nagios-plugins.html">nagios-plugins-standard</a>
+debian package would look up this value automatically, as it would
+make the plugin a lot more useful when my disks fail. At the moment
+it only report a failure when there are no more spares left (it really
+should warn as soon as a disk is failing), and it do not tell me which
+disk(s) is failing when the RAID is running short on disks.</p>
+
+ </div>
+ <div class="tags">
+
+
+ Tags: <a href="http://people.skolelinux.org/pere/blog/tags/english">english</a>, <a href="http://people.skolelinux.org/pere/blog/tags/raid">raid</a>.
+
+
+ </div>
+ </div>
+ <div class="padding"></div>
+
+ <div class="entry">
+ <div class="title">
+ <a href="http://people.skolelinux.org/pere/blog/Automatic_proxy_configuration_with_Debian_Edu___Skolelinux.html">Automatic proxy configuration with Debian Edu / Skolelinux</a>
+ </div>
+ <div class="date">
+ 13th February 2012
+ </div>
+ <div class="body">
+ <p>New in the Squeeze version of
+<a href="http://www.skolelinux.org/">Debian Edu / Skolelinux</a> is the
+ability for clients to automatically configure their proxy settings
+based on their environment. We want all systems on the client to use
+the WPAD based proxy definition fetched from <tt>http://wpad/wpad.dat</tt>, to
+allow sites to control the proxy setting from a central place and make
+sure clients do not have hard coded proxy settings. The schools can
+change the global proxy setting by editing
+<tt>tjener:/etc/debian-edu/www/wpad.dat</tt> and the change propagate
+to all Debian Edu clients in the network.</p>
+
+<p>The problem is that some systems do not understand the WPAD system.
+In other words, how do one get from a WPAD file like this (this is a
+simple one, they can run arbitrary code):</p>
+
+<blockquote><pre>
+function FindProxyForURL(url, host)
+{
+ if (!isResolvable(host) ||
+ isPlainHostName(host) ||
+ dnsDomainIs(host, ".intern"))
+ return "DIRECT";
+ else
+ return "PROXY webcache:3128; DIRECT";
+}
+</pre></blockquote>
+
+<p>to a proxy setting in the process environment looking like this:</p>
+
+<blockquote><pre>
+http_proxy=http://webcache:3128/
+ftp_proxy=http://webcache:3128/
+</pre></blockquote>
+
+<p>To do this conversion I developed a perl script that will execute
+the javascript fragment in the WPAD file and return the proxy that
+would be used for
+<tt><a href="http://www.debian.org/">http://www.debian.org/</a></tt>,
+and insert this extracted proxy URL in <tt>/etc/environment</tt> and
+<tt>/etc/apt/apt.conf</tt>. The perl script wpad-extract work just
+fine in Squeeze, but in Wheezy the library it need to run the
+javascript code is <a href="http://bugs.debian.org/631045">no longer
+able to build</a> because the C library it depended on is now a C++
+library. I hope someone find a solution to that problem before Wheezy
+is frozen. An alternative would be for us to rewrite wpad-extract to
+use some other javascript library currently working in Wheezy, but no
+known alternative is known at the moment.</p>
+
+<p>This automatic proxy system allow the roaming workstation (aka
+laptop) setup in Debian Edu/Squeeze to use the proxy when the laptop
+is connected to the backbone network in a Debian Edu setup, and to
+automatically use any proxy present and announced using the WPAD
+feature when it is connected to other networks. And if no proxy is
+announced, direct connections will be used instead.</p>
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