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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  12  <h1>
  13      <a href="http://people.skolelinux.org/pere/blog/">Petter Reinholdtsen</a>
  14
  15  </h1>
  16
  17 </div>
  18
  19
  20     <div class="entry">
  21       <div class="title">Fixing an hanging debian installer for Debian Edu</div>
  22       <div class="date"> 3rd January 2012</div>
  23       <div class="body"><p>During christmas, I have been working getting the next version of
  24 <a href="http://www.skolelinux.org/">Debian Edu / Skolelinux</a> ready
  25 for release.  The initial problem I looked at was particularly
  26 interesting.</p>
  27
  28 <P>The installer would hang at the end when it was doing it
  29 post-installation configuration, and whatevery I did to try to find
  30 the cause and fix it always worked while I tested it, but never when I
  31 integrated it into the installer and ran the installation from
  32 scratch.  I would try to restart processes, close file descriptors,
  33 remove or create files, and the installer would always unblock and
  34 wrap up its tasks.</p>
  35
  36 <p>Eventually the cause was found.  The kernel was simply running out
  37 of entropy, causing the Kerberos setup to hang waiting for more.
  38 Pressing keys was adding entropy to the kernel, and thus all my tries
  39 to fix the problem worked not because what I was typing to fix it, but
  40 because I was typing.</P>
  41
  42 <p>The fix I implemented was to add a background process looking at
  43 the level of entropy in the kernel (by checking
  44 /proc/sys/kernel/random/entropy_avail), and if it was too small, the
  45 installer will flush the kernel file buffers and do 'find /' to
  46 generate some disk IO.  Disk IO generate entropy in the kernel, and is
  47 one of the few things that can be initated from within the system to
  48 generate entropy.</p>
  49
  50 <p>The fix is in
  51 <a href="http://wiki.debian.org/DebianEdu/Documentation/Squeeze/Installation">beta1
  52 of the Debian Edu/Squeeze</a> version, and we
  53 <a href="http://wiki.debian.org/DebianEdu">welcome more testers and
  54 developers</a>.  We plan to release beta2 this weekend.</p>
  55 </div>
  56
  57       <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>
  58
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  60     </div>
  61
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  65     <div id="sidebar">
  66
  67
  68
  69 <h2>Archive</h2>
  70 <ul>
  71
  72 <li>2013
  73 <ul>
  74
  75 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/01/">January (3)</a></li>
  76
  77 </ul></li>
  78
  79 <li>2012
  80 <ul>
  81
  82 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/01/">January (7)</a></li>
  83
  84 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/02/">February (10)</a></li>
  85
  86 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/03/">March (17)</a></li>
  87
  88 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/04/">April (12)</a></li>
  89
  90 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/05/">May (12)</a></li>
  91
  92 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/06/">June (20)</a></li>
  93
  94 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/07/">July (17)</a></li>
  95
  96 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/08/">August (6)</a></li>
  97
  98 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/09/">September (9)</a></li>
  99
 100 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/10/">October (17)</a></li>
 101
 102 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/11/">November (10)</a></li>
 103
 104 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/12/">December (7)</a></li>
 105
 106 </ul></li>
 107
 108 <li>2011
 109 <ul>
 110
 111 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/01/">January (16)</a></li>
 112
 113 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/02/">February (6)</a></li>
 114
 115 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/03/">March (6)</a></li>
 116
 117 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/04/">April (7)</a></li>
 118
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 120
 121 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/06/">June (2)</a></li>
 122
 123 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/07/">July (7)</a></li>
 124
 125 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/08/">August (6)</a></li>
 126
 127 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/09/">September (4)</a></li>
 128
 129 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/10/">October (2)</a></li>
 130
 131 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/11/">November (3)</a></li>
 132
 133 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/12/">December (1)</a></li>
 134
 135 </ul></li>
 136
 137 <li>2010
 138 <ul>
 139
 140 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/01/">January (2)</a></li>
 141
 142 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/02/">February (1)</a></li>
 143
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 145
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 147
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 149
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 151
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 153
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 155
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 157
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 159
 160 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/11/">November (13)</a></li>
 161
 162 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/12/">December (12)</a></li>
 163
 164 </ul></li>
 165
 166 <li>2009
 167 <ul>
 168
 169 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/01/">January (8)</a></li>
 170
 171 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/02/">February (8)</a></li>
 172
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 174
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 176
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 180
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 182
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 184
 185 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/09/">September (1)</a></li>
 186
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 188
 189 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/11/">November (3)</a></li>
 190
 191 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/12/">December (3)</a></li>
 192
 193 </ul></li>
 194
 195 <li>2008
 196 <ul>
 197
 198 <li><a href="http://people.skolelinux.org/pere/blog/archive/2008/11/">November (5)</a></li>
 199
 200 <li><a href="http://people.skolelinux.org/pere/blog/archive/2008/12/">December (7)</a></li>
 201
 202 </ul></li>
 203
 204 </ul>
 205
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 226
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 228
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 230
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 295  <li><a href="http://people.skolelinux.org/pere/blog/tags/surveillance">surveillance (12)</a></li>
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 299  <li><a href="http://people.skolelinux.org/pere/blog/tags/valg">valg (7)</a></li>
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 306
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