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
  59
  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 (17)</a></li>
  94
  95 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/11/">November (10)</a></li>
  96
  97 </ul></li>
  98
  99 <li>2011
 100 <ul>
 101
 102 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/01/">January (16)</a></li>
 103
 104 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/02/">February (6)</a></li>
 105
 106 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/03/">March (6)</a></li>
 107
 108 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/04/">April (7)</a></li>
 109
 110 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/05/">May (3)</a></li>
 111
 112 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/06/">June (2)</a></li>
 113
 114 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/07/">July (7)</a></li>
 115
 116 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/08/">August (6)</a></li>
 117
 118 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/09/">September (4)</a></li>
 119
 120 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/10/">October (2)</a></li>
 121
 122 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/11/">November (3)</a></li>
 123
 124 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/12/">December (1)</a></li>
 125
 126 </ul></li>
 127
 128 <li>2010
 129 <ul>
 130
 131 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/01/">January (2)</a></li>
 132
 133 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/02/">February (1)</a></li>
 134
 135 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/03/">March (3)</a></li>
 136
 137 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/04/">April (3)</a></li>
 138
 139 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/05/">May (9)</a></li>
 140
 141 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/06/">June (14)</a></li>
 142
 143 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/07/">July (12)</a></li>
 144
 145 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/08/">August (13)</a></li>
 146
 147 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/09/">September (7)</a></li>
 148
 149 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/10/">October (9)</a></li>
 150
 151 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/11/">November (13)</a></li>
 152
 153 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/12/">December (12)</a></li>
 154
 155 </ul></li>
 156
 157 <li>2009
 158 <ul>
 159
 160 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/01/">January (8)</a></li>
 161
 162 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/02/">February (8)</a></li>
 163
 164 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/03/">March (12)</a></li>
 165
 166 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/04/">April (10)</a></li>
 167
 168 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/05/">May (9)</a></li>
 169
 170 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/06/">June (3)</a></li>
 171
 172 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/07/">July (4)</a></li>
 173
 174 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/08/">August (3)</a></li>
 175
 176 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/09/">September (1)</a></li>
 177
 178 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/10/">October (2)</a></li>
 179
 180 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/11/">November (3)</a></li>
 181
 182 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/12/">December (3)</a></li>
 183
 184 </ul></li>
 185
 186 <li>2008
 187 <ul>
 188
 189 <li><a href="http://people.skolelinux.org/pere/blog/archive/2008/11/">November (5)</a></li>
 190
 191 <li><a href="http://people.skolelinux.org/pere/blog/archive/2008/12/">December (7)</a></li>
 192
 193 </ul></li>
 194
 195 </ul>
 196
 197
 198
 199 <h2>Tags</h2>
 200 <ul>
 201
 202  <li><a href="http://people.skolelinux.org/pere/blog/tags/3d-printer">3d-printer (13)</a></li>
 203
 204  <li><a href="http://people.skolelinux.org/pere/blog/tags/amiga">amiga (1)</a></li>
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 211
 212  <li><a href="http://people.skolelinux.org/pere/blog/tags/bsa">bsa (2)</a></li>
 213
 214  <li><a href="http://people.skolelinux.org/pere/blog/tags/debian">debian (57)</a></li>
 215
 216  <li><a href="http://people.skolelinux.org/pere/blog/tags/debian edu">debian edu (116)</a></li>
 217
 218  <li><a href="http://people.skolelinux.org/pere/blog/tags/digistan">digistan (9)</a></li>
 219
 220  <li><a href="http://people.skolelinux.org/pere/blog/tags/docbook">docbook (7)</a></li>
 221
 222  <li><a href="http://people.skolelinux.org/pere/blog/tags/drivstoffpriser">drivstoffpriser (4)</a></li>
 223
 224  <li><a href="http://people.skolelinux.org/pere/blog/tags/english">english (160)</a></li>
 225
 226  <li><a href="http://people.skolelinux.org/pere/blog/tags/fiksgatami">fiksgatami (20)</a></li>
 227
 228  <li><a href="http://people.skolelinux.org/pere/blog/tags/fildeling">fildeling (12)</a></li>
 229
 230  <li><a href="http://people.skolelinux.org/pere/blog/tags/freeculture">freeculture (9)</a></li>
 231
 232  <li><a href="http://people.skolelinux.org/pere/blog/tags/frikanalen">frikanalen (9)</a></li>
 233
 234  <li><a href="http://people.skolelinux.org/pere/blog/tags/intervju">intervju (32)</a></li>
 235
 236  <li><a href="http://people.skolelinux.org/pere/blog/tags/kart">kart (17)</a></li>
 237
 238  <li><a href="http://people.skolelinux.org/pere/blog/tags/ldap">ldap (8)</a></li>
 239
 240  <li><a href="http://people.skolelinux.org/pere/blog/tags/lenker">lenker (5)</a></li>
 241
 242  <li><a href="http://people.skolelinux.org/pere/blog/tags/ltsp">ltsp (1)</a></li>
 243
 244  <li><a href="http://people.skolelinux.org/pere/blog/tags/multimedia">multimedia (25)</a></li>
 245
 246  <li><a href="http://people.skolelinux.org/pere/blog/tags/norsk">norsk (216)</a></li>
 247
 248  <li><a href="http://people.skolelinux.org/pere/blog/tags/nuug">nuug (147)</a></li>
 249
 250  <li><a href="http://people.skolelinux.org/pere/blog/tags/offentlig innsyn">offentlig innsyn (6)</a></li>
 251
 252  <li><a href="http://people.skolelinux.org/pere/blog/tags/open311">open311 (2)</a></li>
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 254  <li><a href="http://people.skolelinux.org/pere/blog/tags/opphavsrett">opphavsrett (39)</a></li>
 255
 256  <li><a href="http://people.skolelinux.org/pere/blog/tags/personvern">personvern (60)</a></li>
 257
 258  <li><a href="http://people.skolelinux.org/pere/blog/tags/raid">raid (1)</a></li>
 259
 260  <li><a href="http://people.skolelinux.org/pere/blog/tags/reprap">reprap (11)</a></li>
 261
 262  <li><a href="http://people.skolelinux.org/pere/blog/tags/rfid">rfid (2)</a></li>
 263
 264  <li><a href="http://people.skolelinux.org/pere/blog/tags/robot">robot (4)</a></li>
 265
 266  <li><a href="http://people.skolelinux.org/pere/blog/tags/rss">rss (1)</a></li>
 267
 268  <li><a href="http://people.skolelinux.org/pere/blog/tags/ruter">ruter (4)</a></li>
 269
 270  <li><a href="http://people.skolelinux.org/pere/blog/tags/scraperwiki">scraperwiki (2)</a></li>
 271
 272  <li><a href="http://people.skolelinux.org/pere/blog/tags/sikkerhet">sikkerhet (28)</a></li>
 273
 274  <li><a href="http://people.skolelinux.org/pere/blog/tags/sitesummary">sitesummary (4)</a></li>
 275
 276  <li><a href="http://people.skolelinux.org/pere/blog/tags/skepsis">skepsis (4)</a></li>
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 278  <li><a href="http://people.skolelinux.org/pere/blog/tags/standard">standard (39)</a></li>
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 280  <li><a href="http://people.skolelinux.org/pere/blog/tags/stavekontroll">stavekontroll (3)</a></li>
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 282  <li><a href="http://people.skolelinux.org/pere/blog/tags/stortinget">stortinget (5)</a></li>
 283
 284  <li><a href="http://people.skolelinux.org/pere/blog/tags/surveillance">surveillance (12)</a></li>
 285
 286  <li><a href="http://people.skolelinux.org/pere/blog/tags/valg">valg (7)</a></li>
 287
 288  <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/vitenskap">vitenskap (4)</a></li>
 291
 292  <li><a href="http://people.skolelinux.org/pere/blog/tags/web">web (26)</a></li>
 293
 294 </ul>
 295
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