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+ <title>Petter Reinholdtsen: Fixing an hanging debian installer for Debian Edu</title>
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+ <h1>
+ <a href="http://people.skolelinux.org/pere/blog/">Petter Reinholdtsen</a>
+
+ </h1>
+
+</div>
+
+
+ <div class="entry">
+ <div class="title">Fixing an hanging debian installer for Debian Edu</div>
+ <div class="date"> 3rd January 2012</div>
+ <div class="body"><p>During christmas, I have been working getting the next version of
+<a href="http://www.skolelinux.org/">Debian Edu / Skolelinux</a> ready
+for release. The initial problem I looke at was particularly
+interesting.</p>
+
+<P>The installer would hang at the end when it was doing it
+post-installation configuration, and whatevery I did to try to find
+the cause and fix it always worked while I tested it, but never when I
+integrated it into the installer and ran the installation from
+scratch. I would try to restart processes, close file descriptors,
+remove or create files, and the installer would always unblock and
+wrap up its tasks.</p>
+
+<p>Eventually the cause was found. The kernel was simply running out
+of entropy, causing the Kerberos setup to hang waiting for more.
+Pressing keys was adding entropy to the kernel, and thus all my tries
+to fix the problem worked not because what I was typing to fix it, but
+because I was typing.</P>
+
+<p>The fix I implemented was to add a background process looking at
+the level of entropy in the kernel (by checking
+/proc/sys/kernel/random/entropy_avail), and if it was too small, the
+installer will flush the kernel file buffers and do 'find /' to
+generate some disk IO. Disk IO generate entropy in the kernel, and is
+one of the few things that can be initated from within the system to
+generate entropy.</p>
+
+<p>The fix is in
+<a href="http://wiki.debian.org/DebianEdu/Documentation/Squeeze/Installation">beta1
+of the Debian Edu/Squeeze</a> version, and we
+<a href="http://wiki.debian.org/DebianEdu">welcome more testers and
+developers</a>. We plan to release beta2 this weekend.</p>
+</div>
+
+ <div class="tags">Tags: <a href="http://people.skolelinux.org/pere/blog/tags/debian edu">debian edu</a>, <a href="http://people.skolelinux.org/pere/blog/tags/english">english</a>.</div>
+
+
+ </div>
+
+
+
+
+ <div id="sidebar">
+
+
+
+<h2>Archive</h2>
+<ul>
+
+<li>2012
+<ul>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2012/01/">January (1)</a></li>
+
+</ul></li>
+
+<li>2011
+<ul>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2011/01/">January (16)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2011/02/">February (6)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2011/03/">March (6)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2011/04/">April (7)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2011/05/">May (3)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2011/06/">June (2)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2011/07/">July (7)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2011/08/">August (6)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2011/09/">September (4)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2011/10/">October (2)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2011/11/">November (3)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2011/12/">December (1)</a></li>
+
+</ul></li>
+
+<li>2010
+<ul>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2010/01/">January (2)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2010/02/">February (1)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2010/03/">March (3)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2010/04/">April (3)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2010/05/">May (9)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2010/06/">June (14)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2010/07/">July (12)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2010/08/">August (13)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2010/09/">September (7)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2010/10/">October (9)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2010/11/">November (13)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2010/12/">December (12)</a></li>
+
+</ul></li>
+
+<li>2009
+<ul>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2009/01/">January (8)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2009/02/">February (8)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2009/03/">March (12)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2009/04/">April (10)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2009/05/">May (9)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2009/06/">June (3)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2009/07/">July (4)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2009/08/">August (3)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2009/09/">September (1)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2009/10/">October (2)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2009/11/">November (3)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2009/12/">December (3)</a></li>
+
+</ul></li>
+
+<li>2008
+<ul>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2008/11/">November (5)</a></li>
+
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2008/12/">December (7)</a></li>
+
+</ul></li>
+
+</ul>
+
+
+
+<h2>Tags</h2>
+<ul>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/3d-printer">3d-printer (13)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/amiga">amiga (1)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/aros">aros (1)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/bitcoin">bitcoin (2)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/bootsystem">bootsystem (12)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/bsa">bsa (2)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/debian">debian (54)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/debian edu">debian edu (65)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/digistan">digistan (7)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/english">english (99)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/fiksgatami">fiksgatami (13)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/fildeling">fildeling (12)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/intervju">intervju (11)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/kart">kart (15)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/ldap">ldap (8)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/lenker">lenker (4)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/ltsp">ltsp (1)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/multimedia">multimedia (14)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/norsk">norsk (141)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/nuug">nuug (119)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/open311">open311 (2)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/opphavsrett">opphavsrett (24)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/personvern">personvern (46)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/reprap">reprap (11)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/rfid">rfid (2)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/robot">robot (4)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/rss">rss (1)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/sikkerhet">sikkerhet (23)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/sitesummary">sitesummary (3)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/standard">standard (24)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/stavekontroll">stavekontroll (1)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/stortinget">stortinget (3)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/surveillance">surveillance (9)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/valg">valg (6)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/video">video (22)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/vitenskap">vitenskap (1)</a></li>
+
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/web">web (17)</a></li>
+
+</ul>
+
+
+ </div>
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