blog/Fixing_an_hanging_debian_installer_for_Debian_Edu.html

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   6     <title>Petter Reinholdtsen: Fixing an hanging debian installer for Debian Edu</title>
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  14  <h1>
  15      <a href="http://people.skolelinux.org/pere/blog/">Petter Reinholdtsen</a>
  16
  17  </h1>
  18
  19 </div>
  20
  21
  22     <div class="entry">
  23       <div class="title">Fixing an hanging debian installer for Debian Edu</div>
  24       <div class="date"> 3rd January 2012</div>
  25       <div class="body"><p>During christmas, I have been working getting the next version of
  26 <a href="http://www.skolelinux.org/">Debian Edu / Skolelinux</a> ready
  27 for release.  The initial problem I looked at was particularly
  28 interesting.</p>
  29
  30 <P>The installer would hang at the end when it was doing it
  31 post-installation configuration, and whatevery I did to try to find
  32 the cause and fix it always worked while I tested it, but never when I
  33 integrated it into the installer and ran the installation from
  34 scratch.  I would try to restart processes, close file descriptors,
  35 remove or create files, and the installer would always unblock and
  36 wrap up its tasks.</p>
  37
  38 <p>Eventually the cause was found.  The kernel was simply running out
  39 of entropy, causing the Kerberos setup to hang waiting for more.
  40 Pressing keys was adding entropy to the kernel, and thus all my tries
  41 to fix the problem worked not because what I was typing to fix it, but
  42 because I was typing.</P>
  43
  44 <p>The fix I implemented was to add a background process looking at
  45 the level of entropy in the kernel (by checking
  46 /proc/sys/kernel/random/entropy_avail), and if it was too small, the
  47 installer will flush the kernel file buffers and do 'find /' to
  48 generate some disk IO.  Disk IO generate entropy in the kernel, and is
  49 one of the few things that can be initated from within the system to
  50 generate entropy.</p>
  51
  52 <p>The fix is in
  53 <a href="http://wiki.debian.org/DebianEdu/Documentation/Squeeze/Installation">beta1
  54 of the Debian Edu/Squeeze</a> version, and we
  55 <a href="http://wiki.debian.org/DebianEdu">welcome more testers and
  56 developers</a>.  We plan to release beta2 this weekend.</p>
  57 </div>
  58
  59       <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>
  60
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  62     </div>
  63
  64
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  67     <div id="sidebar">
  68
  69
  70
  71 <h2>Archive</h2>
  72 <ul>
  73
  74 <li>2013
  75 <ul>
  76
  77 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/01/">January (11)</a></li>
  78
  79 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/02/">February (9)</a></li>
  80
  81 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/03/">March (9)</a></li>
  82
  83 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/04/">April (6)</a></li>
  84
  85 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/05/">May (9)</a></li>
  86
  87 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/06/">June (10)</a></li>
  88
  89 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/07/">July (7)</a></li>
  90
  91 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/08/">August (3)</a></li>
  92
  93 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/09/">September (2)</a></li>
  94
  95 </ul></li>
  96
  97 <li>2012
  98 <ul>
  99
 100 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/01/">January (7)</a></li>
 101
 102 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/02/">February (10)</a></li>
 103
 104 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/03/">March (17)</a></li>
 105
 106 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/04/">April (12)</a></li>
 107
 108 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/05/">May (12)</a></li>
 109
 110 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/06/">June (20)</a></li>
 111
 112 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/07/">July (17)</a></li>
 113
 114 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/08/">August (6)</a></li>
 115
 116 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/09/">September (9)</a></li>
 117
 118 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/10/">October (17)</a></li>
 119
 120 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/11/">November (10)</a></li>
 121
 122 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/12/">December (7)</a></li>
 123
 124 </ul></li>
 125
 126 <li>2011
 127 <ul>
 128
 129 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/01/">January (16)</a></li>
 130
 131 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/02/">February (6)</a></li>
 132
 133 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/03/">March (6)</a></li>
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 135 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/04/">April (7)</a></li>
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 137 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/05/">May (3)</a></li>
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 139 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/06/">June (2)</a></li>
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 141 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/07/">July (7)</a></li>
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 143 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/08/">August (6)</a></li>
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 145 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/09/">September (4)</a></li>
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 147 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/10/">October (2)</a></li>
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 149 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/11/">November (3)</a></li>
 150
 151 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/12/">December (1)</a></li>
 152
 153 </ul></li>
 154
 155 <li>2010
 156 <ul>
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 158 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/01/">January (2)</a></li>
 159
 160 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/02/">February (1)</a></li>
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 170 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/07/">July (12)</a></li>
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 172 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/08/">August (13)</a></li>
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 174 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/09/">September (7)</a></li>
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 176 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/10/">October (9)</a></li>
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 178 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/11/">November (13)</a></li>
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 180 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/12/">December (12)</a></li>
 181
 182 </ul></li>
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 184 <li>2009
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 207 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/11/">November (3)</a></li>
 208
 209 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/12/">December (3)</a></li>
 210
 211 </ul></li>
 212
 213 <li>2008
 214 <ul>
 215
 216 <li><a href="http://people.skolelinux.org/pere/blog/archive/2008/11/">November (5)</a></li>
 217
 218 <li><a href="http://people.skolelinux.org/pere/blog/archive/2008/12/">December (7)</a></li>
 219
 220 </ul></li>
 221
 222 </ul>
 223
 224
 225
 226 <h2>Tags</h2>
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 242
 243  <li><a href="http://people.skolelinux.org/pere/blog/tags/debian">debian (85)</a></li>
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 245  <li><a href="http://people.skolelinux.org/pere/blog/tags/debian edu">debian edu (139)</a></li>
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 327  <li><a href="http://people.skolelinux.org/pere/blog/tags/web">web (27)</a></li>
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 329 </ul>
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