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
  62
  63
  64
  65     <div id="sidebar">
  66
  67
  68
  69 <h2>Archive</h2>
  70 <ul>
  71
  72 <li>2012
  73 <ul>
  74
  75 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/01/">January (7)</a></li>
  76
  77 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/02/">February (10)</a></li>
  78
  79 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/03/">March (17)</a></li>
  80
  81 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/04/">April (12)</a></li>
  82
  83 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/05/">May (12)</a></li>
  84
  85 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/06/">June (20)</a></li>
  86
  87 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/07/">July (17)</a></li>
  88
  89 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/08/">August (6)</a></li>
  90
  91 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/09/">September (9)</a></li>
  92
  93 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/10/">October (16)</a></li>
  94
  95 </ul></li>
  96
  97 <li>2011
  98 <ul>
  99
 100 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/01/">January (16)</a></li>
 101
 102 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/02/">February (6)</a></li>
 103
 104 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/03/">March (6)</a></li>
 105
 106 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/04/">April (7)</a></li>
 107
 108 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/05/">May (3)</a></li>
 109
 110 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/06/">June (2)</a></li>
 111
 112 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/07/">July (7)</a></li>
 113
 114 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/08/">August (6)</a></li>
 115
 116 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/09/">September (4)</a></li>
 117
 118 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/10/">October (2)</a></li>
 119
 120 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/11/">November (3)</a></li>
 121
 122 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/12/">December (1)</a></li>
 123
 124 </ul></li>
 125
 126 <li>2010
 127 <ul>
 128
 129 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/01/">January (2)</a></li>
 130
 131 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/02/">February (1)</a></li>
 132
 133 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/03/">March (3)</a></li>
 134
 135 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/04/">April (3)</a></li>
 136
 137 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/05/">May (9)</a></li>
 138
 139 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/06/">June (14)</a></li>
 140
 141 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/07/">July (12)</a></li>
 142
 143 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/08/">August (13)</a></li>
 144
 145 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/09/">September (7)</a></li>
 146
 147 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/10/">October (9)</a></li>
 148
 149 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/11/">November (13)</a></li>
 150
 151 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/12/">December (12)</a></li>
 152
 153 </ul></li>
 154
 155 <li>2009
 156 <ul>
 157
 158 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/01/">January (8)</a></li>
 159
 160 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/02/">February (8)</a></li>
 161
 162 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/03/">March (12)</a></li>
 163
 164 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/04/">April (10)</a></li>
 165
 166 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/05/">May (9)</a></li>
 167
 168 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/06/">June (3)</a></li>
 169
 170 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/07/">July (4)</a></li>
 171
 172 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/08/">August (3)</a></li>
 173
 174 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/09/">September (1)</a></li>
 175
 176 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/10/">October (2)</a></li>
 177
 178 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/11/">November (3)</a></li>
 179
 180 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/12/">December (3)</a></li>
 181
 182 </ul></li>
 183
 184 <li>2008
 185 <ul>
 186
 187 <li><a href="http://people.skolelinux.org/pere/blog/archive/2008/11/">November (5)</a></li>
 188
 189 <li><a href="http://people.skolelinux.org/pere/blog/archive/2008/12/">December (7)</a></li>
 190
 191 </ul></li>
 192
 193 </ul>
 194
 195
 196
 197 <h2>Tags</h2>
 198 <ul>
 199
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 210  <li><a href="http://people.skolelinux.org/pere/blog/tags/bsa">bsa (2)</a></li>
 211
 212  <li><a href="http://people.skolelinux.org/pere/blog/tags/debian">debian (57)</a></li>
 213
 214  <li><a href="http://people.skolelinux.org/pere/blog/tags/debian edu">debian edu (115)</a></li>
 215
 216  <li><a href="http://people.skolelinux.org/pere/blog/tags/digistan">digistan (9)</a></li>
 217
 218  <li><a href="http://people.skolelinux.org/pere/blog/tags/docbook">docbook (7)</a></li>
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 220  <li><a href="http://people.skolelinux.org/pere/blog/tags/drivstoffpriser">drivstoffpriser (4)</a></li>
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 222  <li><a href="http://people.skolelinux.org/pere/blog/tags/english">english (155)</a></li>
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 224  <li><a href="http://people.skolelinux.org/pere/blog/tags/fiksgatami">fiksgatami (19)</a></li>
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 226  <li><a href="http://people.skolelinux.org/pere/blog/tags/fildeling">fildeling (12)</a></li>
 227
 228  <li><a href="http://people.skolelinux.org/pere/blog/tags/freeculture">freeculture (8)</a></li>
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 230  <li><a href="http://people.skolelinux.org/pere/blog/tags/frikanalen">frikanalen (8)</a></li>
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 232  <li><a href="http://people.skolelinux.org/pere/blog/tags/intervju">intervju (31)</a></li>
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 234  <li><a href="http://people.skolelinux.org/pere/blog/tags/kart">kart (17)</a></li>
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 236  <li><a href="http://people.skolelinux.org/pere/blog/tags/ldap">ldap (8)</a></li>
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 242  <li><a href="http://people.skolelinux.org/pere/blog/tags/multimedia">multimedia (25)</a></li>
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 250  <li><a href="http://people.skolelinux.org/pere/blog/tags/open311">open311 (2)</a></li>
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 252  <li><a href="http://people.skolelinux.org/pere/blog/tags/opphavsrett">opphavsrett (37)</a></li>
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 254  <li><a href="http://people.skolelinux.org/pere/blog/tags/personvern">personvern (54)</a></li>
 255
 256  <li><a href="http://people.skolelinux.org/pere/blog/tags/raid">raid (1)</a></li>
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 258  <li><a href="http://people.skolelinux.org/pere/blog/tags/reprap">reprap (11)</a></li>
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 260  <li><a href="http://people.skolelinux.org/pere/blog/tags/rfid">rfid (2)</a></li>
 261
 262  <li><a href="http://people.skolelinux.org/pere/blog/tags/robot">robot (4)</a></li>
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 264  <li><a href="http://people.skolelinux.org/pere/blog/tags/rss">rss (1)</a></li>
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 266  <li><a href="http://people.skolelinux.org/pere/blog/tags/ruter">ruter (4)</a></li>
 267
 268  <li><a href="http://people.skolelinux.org/pere/blog/tags/scraperwiki">scraperwiki (2)</a></li>
 269
 270  <li><a href="http://people.skolelinux.org/pere/blog/tags/sikkerhet">sikkerhet (24)</a></li>
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 272  <li><a href="http://people.skolelinux.org/pere/blog/tags/sitesummary">sitesummary (4)</a></li>
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 274  <li><a href="http://people.skolelinux.org/pere/blog/tags/skepsis">skepsis (4)</a></li>
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 282  <li><a href="http://people.skolelinux.org/pere/blog/tags/surveillance">surveillance (11)</a></li>
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 284  <li><a href="http://people.skolelinux.org/pere/blog/tags/valg">valg (7)</a></li>
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 286  <li><a href="http://people.skolelinux.org/pere/blog/tags/video">video (35)</a></li>
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 290  <li><a href="http://people.skolelinux.org/pere/blog/tags/web">web (26)</a></li>
 291
 292 </ul>
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