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>2015
  75 <ul>
  76
  77 <li><a href="http://people.skolelinux.org/pere/blog/archive/2015/01/">January (7)</a></li>
  78
  79 <li><a href="http://people.skolelinux.org/pere/blog/archive/2015/02/">February (6)</a></li>
  80
  81 <li><a href="http://people.skolelinux.org/pere/blog/archive/2015/03/">March (1)</a></li>
  82
  83 <li><a href="http://people.skolelinux.org/pere/blog/archive/2015/04/">April (4)</a></li>
  84
  85 <li><a href="http://people.skolelinux.org/pere/blog/archive/2015/05/">May (3)</a></li>
  86
  87 <li><a href="http://people.skolelinux.org/pere/blog/archive/2015/06/">June (4)</a></li>
  88
  89 <li><a href="http://people.skolelinux.org/pere/blog/archive/2015/07/">July (6)</a></li>
  90
  91 <li><a href="http://people.skolelinux.org/pere/blog/archive/2015/08/">August (2)</a></li>
  92
  93 <li><a href="http://people.skolelinux.org/pere/blog/archive/2015/09/">September (2)</a></li>
  94
  95 <li><a href="http://people.skolelinux.org/pere/blog/archive/2015/10/">October (8)</a></li>
  96
  97 </ul></li>
  98
  99 <li>2014
 100 <ul>
 101
 102 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/01/">January (2)</a></li>
 103
 104 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/02/">February (3)</a></li>
 105
 106 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/03/">March (8)</a></li>
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 108 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/04/">April (7)</a></li>
 109
 110 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/05/">May (1)</a></li>
 111
 112 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/06/">June (2)</a></li>
 113
 114 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/07/">July (2)</a></li>
 115
 116 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/08/">August (2)</a></li>
 117
 118 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/09/">September (5)</a></li>
 119
 120 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/10/">October (6)</a></li>
 121
 122 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/11/">November (3)</a></li>
 123
 124 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/12/">December (5)</a></li>
 125
 126 </ul></li>
 127
 128 <li>2013
 129 <ul>
 130
 131 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/01/">January (11)</a></li>
 132
 133 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/02/">February (9)</a></li>
 134
 135 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/03/">March (9)</a></li>
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 137 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/04/">April (6)</a></li>
 138
 139 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/05/">May (9)</a></li>
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 141 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/06/">June (10)</a></li>
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 143 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/07/">July (7)</a></li>
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 145 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/08/">August (3)</a></li>
 146
 147 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/09/">September (5)</a></li>
 148
 149 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/10/">October (7)</a></li>
 150
 151 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/11/">November (9)</a></li>
 152
 153 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/12/">December (3)</a></li>
 154
 155 </ul></li>
 156
 157 <li>2012
 158 <ul>
 159
 160 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/01/">January (7)</a></li>
 161
 162 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/02/">February (10)</a></li>
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 164 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/03/">March (17)</a></li>
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 180 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/11/">November (10)</a></li>
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 182 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/12/">December (7)</a></li>
 183
 184 </ul></li>
 185
 186 <li>2011
 187 <ul>
 188
 189 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/01/">January (16)</a></li>
 190
 191 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/02/">February (6)</a></li>
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 193 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/03/">March (6)</a></li>
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 195 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/04/">April (7)</a></li>
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 211 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/12/">December (1)</a></li>
 212
 213 </ul></li>
 214
 215 <li>2010
 216 <ul>
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 218 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/01/">January (2)</a></li>
 219
 220 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/02/">February (1)</a></li>
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 226 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/05/">May (9)</a></li>
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 230 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/07/">July (12)</a></li>
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 232 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/08/">August (13)</a></li>
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 234 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/09/">September (7)</a></li>
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 236 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/10/">October (9)</a></li>
 237
 238 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/11/">November (13)</a></li>
 239
 240 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/12/">December (12)</a></li>
 241
 242 </ul></li>
 243
 244 <li>2009
 245 <ul>
 246
 247 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/01/">January (8)</a></li>
 248
 249 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/02/">February (8)</a></li>
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 251 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/03/">March (12)</a></li>
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 253 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/04/">April (10)</a></li>
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 255 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/05/">May (9)</a></li>
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 262
 263 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/09/">September (1)</a></li>
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 265 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/10/">October (2)</a></li>
 266
 267 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/11/">November (3)</a></li>
 268
 269 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/12/">December (3)</a></li>
 270
 271 </ul></li>
 272
 273 <li>2008
 274 <ul>
 275
 276 <li><a href="http://people.skolelinux.org/pere/blog/archive/2008/11/">November (5)</a></li>
 277
 278 <li><a href="http://people.skolelinux.org/pere/blog/archive/2008/12/">December (7)</a></li>
 279
 280 </ul></li>
 281
 282 </ul>
 283
 284
 285
 286 <h2>Tags</h2>
 287 <ul>
 288
 289  <li><a href="http://people.skolelinux.org/pere/blog/tags/3d-printer">3d-printer (13)</a></li>
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 291  <li><a href="http://people.skolelinux.org/pere/blog/tags/amiga">amiga (1)</a></li>
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 407     <p style="text-align: right">
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