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
  61
  62     </div>
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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 (2)</a></li>
  86
  87 </ul></li>
  88
  89 <li>2014
  90 <ul>
  91
  92 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/01/">January (2)</a></li>
  93
  94 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/02/">February (3)</a></li>
  95
  96 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/03/">March (8)</a></li>
  97
  98 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/04/">April (7)</a></li>
  99
 100 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/05/">May (1)</a></li>
 101
 102 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/06/">June (2)</a></li>
 103
 104 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/07/">July (2)</a></li>
 105
 106 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/08/">August (2)</a></li>
 107
 108 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/09/">September (5)</a></li>
 109
 110 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/10/">October (6)</a></li>
 111
 112 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/11/">November (3)</a></li>
 113
 114 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/12/">December (5)</a></li>
 115
 116 </ul></li>
 117
 118 <li>2013
 119 <ul>
 120
 121 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/01/">January (11)</a></li>
 122
 123 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/02/">February (9)</a></li>
 124
 125 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/03/">March (9)</a></li>
 126
 127 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/04/">April (6)</a></li>
 128
 129 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/05/">May (9)</a></li>
 130
 131 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/06/">June (10)</a></li>
 132
 133 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/07/">July (7)</a></li>
 134
 135 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/08/">August (3)</a></li>
 136
 137 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/09/">September (5)</a></li>
 138
 139 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/10/">October (7)</a></li>
 140
 141 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/11/">November (9)</a></li>
 142
 143 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/12/">December (3)</a></li>
 144
 145 </ul></li>
 146
 147 <li>2012
 148 <ul>
 149
 150 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/01/">January (7)</a></li>
 151
 152 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/02/">February (10)</a></li>
 153
 154 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/03/">March (17)</a></li>
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 156 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/04/">April (12)</a></li>
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 158 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/05/">May (12)</a></li>
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 160 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/06/">June (20)</a></li>
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 166 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/09/">September (9)</a></li>
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 168 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/10/">October (17)</a></li>
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 170 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/11/">November (10)</a></li>
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 172 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/12/">December (7)</a></li>
 173
 174 </ul></li>
 175
 176 <li>2011
 177 <ul>
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 179 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/01/">January (16)</a></li>
 180
 181 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/02/">February (6)</a></li>
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 183 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/03/">March (6)</a></li>
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 185 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/04/">April (7)</a></li>
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 189 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/06/">June (2)</a></li>
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 191 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/07/">July (7)</a></li>
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 195 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/09/">September (4)</a></li>
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 199 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/11/">November (3)</a></li>
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 201 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/12/">December (1)</a></li>
 202
 203 </ul></li>
 204
 205 <li>2010
 206 <ul>
 207
 208 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/01/">January (2)</a></li>
 209
 210 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/02/">February (1)</a></li>
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 212 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/03/">March (3)</a></li>
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 214 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/04/">April (3)</a></li>
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 216 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/05/">May (9)</a></li>
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 220 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/07/">July (12)</a></li>
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 222 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/08/">August (13)</a></li>
 223
 224 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/09/">September (7)</a></li>
 225
 226 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/10/">October (9)</a></li>
 227
 228 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/11/">November (13)</a></li>
 229
 230 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/12/">December (12)</a></li>
 231
 232 </ul></li>
 233
 234 <li>2009
 235 <ul>
 236
 237 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/01/">January (8)</a></li>
 238
 239 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/02/">February (8)</a></li>
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 241 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/03/">March (12)</a></li>
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 243 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/04/">April (10)</a></li>
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 245 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/05/">May (9)</a></li>
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 247 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/06/">June (3)</a></li>
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 249 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/07/">July (4)</a></li>
 250
 251 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/08/">August (3)</a></li>
 252
 253 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/09/">September (1)</a></li>
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 255 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/10/">October (2)</a></li>
 256
 257 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/11/">November (3)</a></li>
 258
 259 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/12/">December (3)</a></li>
 260
 261 </ul></li>
 262
 263 <li>2008
 264 <ul>
 265
 266 <li><a href="http://people.skolelinux.org/pere/blog/archive/2008/11/">November (5)</a></li>
 267
 268 <li><a href="http://people.skolelinux.org/pere/blog/archive/2008/12/">December (7)</a></li>
 269
 270 </ul></li>
 271
 272 </ul>
 273
 274
 275
 276 <h2>Tags</h2>
 277 <ul>
 278
 279  <li><a href="http://people.skolelinux.org/pere/blog/tags/3d-printer">3d-printer (13)</a></li>
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 295  <li><a href="http://people.skolelinux.org/pere/blog/tags/debian">debian (109)</a></li>
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 297  <li><a href="http://people.skolelinux.org/pere/blog/tags/debian edu">debian edu (153)</a></li>
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 391 </ul>
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