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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  70
  71 <h2>Archive</h2>
  72 <ul>
  73
  74 <li>2016
  75 <ul>
  76
  77 <li><a href="http://people.skolelinux.org/pere/blog/archive/2016/01/">January (3)</a></li>
  78
  79 <li><a href="http://people.skolelinux.org/pere/blog/archive/2016/02/">February (2)</a></li>
  80
  81 <li><a href="http://people.skolelinux.org/pere/blog/archive/2016/03/">March (3)</a></li>
  82
  83 <li><a href="http://people.skolelinux.org/pere/blog/archive/2016/04/">April (5)</a></li>
  84
  85 </ul></li>
  86
  87 <li>2015
  88 <ul>
  89
  90 <li><a href="http://people.skolelinux.org/pere/blog/archive/2015/01/">January (7)</a></li>
  91
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 113
 114 </ul></li>
 115
 116 <li>2014
 117 <ul>
 118
 119 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/01/">January (2)</a></li>
 120
 121 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/02/">February (3)</a></li>
 122
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 126
 127 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/05/">May (1)</a></li>
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 129 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/06/">June (2)</a></li>
 130
 131 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/07/">July (2)</a></li>
 132
 133 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/08/">August (2)</a></li>
 134
 135 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/09/">September (5)</a></li>
 136
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 138
 139 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/11/">November (3)</a></li>
 140
 141 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/12/">December (5)</a></li>
 142
 143 </ul></li>
 144
 145 <li>2013
 146 <ul>
 147
 148 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/01/">January (11)</a></li>
 149
 150 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/02/">February (9)</a></li>
 151
 152 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/03/">March (9)</a></li>
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 164 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/09/">September (5)</a></li>
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 166 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/10/">October (7)</a></li>
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 168 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/11/">November (9)</a></li>
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 170 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/12/">December (3)</a></li>
 171
 172 </ul></li>
 173
 174 <li>2012
 175 <ul>
 176
 177 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/01/">January (7)</a></li>
 178
 179 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/02/">February (10)</a></li>
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 185 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/05/">May (12)</a></li>
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 191 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/08/">August (6)</a></li>
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 193 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/09/">September (9)</a></li>
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 195 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/10/">October (17)</a></li>
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 197 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/11/">November (10)</a></li>
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 199 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/12/">December (7)</a></li>
 200
 201 </ul></li>
 202
 203 <li>2011
 204 <ul>
 205
 206 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/01/">January (16)</a></li>
 207
 208 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/02/">February (6)</a></li>
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 224 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/10/">October (2)</a></li>
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 226 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/11/">November (3)</a></li>
 227
 228 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/12/">December (1)</a></li>
 229
 230 </ul></li>
 231
 232 <li>2010
 233 <ul>
 234
 235 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/01/">January (2)</a></li>
 236
 237 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/02/">February (1)</a></li>
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 243 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/05/">May (9)</a></li>
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 251 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/09/">September (7)</a></li>
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 253 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/10/">October (9)</a></li>
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 255 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/11/">November (13)</a></li>
 256
 257 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/12/">December (12)</a></li>
 258
 259 </ul></li>
 260
 261 <li>2009
 262 <ul>
 263
 264 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/01/">January (8)</a></li>
 265
 266 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/02/">February (8)</a></li>
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 270 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/04/">April (10)</a></li>
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 284 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/11/">November (3)</a></li>
 285
 286 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/12/">December (3)</a></li>
 287
 288 </ul></li>
 289
 290 <li>2008
 291 <ul>
 292
 293 <li><a href="http://people.skolelinux.org/pere/blog/archive/2008/11/">November (5)</a></li>
 294
 295 <li><a href="http://people.skolelinux.org/pere/blog/archive/2008/12/">December (7)</a></li>
 296
 297 </ul></li>
 298
 299 </ul>
 300
 301
 302
 303 <h2>Tags</h2>
 304 <ul>
 305
 306  <li><a href="http://people.skolelinux.org/pere/blog/tags/3d-printer">3d-printer (13)</a></li>
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 308  <li><a href="http://people.skolelinux.org/pere/blog/tags/amiga">amiga (1)</a></li>
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 322  <li><a href="http://people.skolelinux.org/pere/blog/tags/debian">debian (124)</a></li>
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 324  <li><a href="http://people.skolelinux.org/pere/blog/tags/debian edu">debian edu (154)</a></li>
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 326  <li><a href="http://people.skolelinux.org/pere/blog/tags/digistan">digistan (10)</a></li>
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 402  <li><a href="http://people.skolelinux.org/pere/blog/tags/standard">standard (49)</a></li>
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 420  <li><a href="http://people.skolelinux.org/pere/blog/tags/web">web (38)</a></li>
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 422 </ul>
 423
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