blog/Fixing_an_hanging_debian_installer_for_Debian_Edu.html

   1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
   2           "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
   3 <html xmlns="http://www.w3.org/1999/xhtml" dir="ltr">
   4   <head>
   5     <meta http-equiv="Content-Type" content="text/html;charset=utf-8" />
   6     <title>Petter Reinholdtsen: Fixing an hanging debian installer for Debian Edu</title>
   7     <link rel="stylesheet" type="text/css" media="screen" href="http://people.skolelinux.org/pere/blog/style.css" />
   8     <link rel="stylesheet" type="text/css" media="screen" href="http://people.skolelinux.org/pere/blog/vim.css" />
   9   </head>
  10   <body>
  11     <div class="title">
  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 (10)</a></li>
  82
  83 </ul></li>
  84
  85 <li>2011
  86 <ul>
  87
  88 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/01/">January (16)</a></li>
  89
  90 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/02/">February (6)</a></li>
  91
  92 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/03/">March (6)</a></li>
  93
  94 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/04/">April (7)</a></li>
  95
  96 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/05/">May (3)</a></li>
  97
  98 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/06/">June (2)</a></li>
  99
 100 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/07/">July (7)</a></li>
 101
 102 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/08/">August (6)</a></li>
 103
 104 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/09/">September (4)</a></li>
 105
 106 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/10/">October (2)</a></li>
 107
 108 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/11/">November (3)</a></li>
 109
 110 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/12/">December (1)</a></li>
 111
 112 </ul></li>
 113
 114 <li>2010
 115 <ul>
 116
 117 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/01/">January (2)</a></li>
 118
 119 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/02/">February (1)</a></li>
 120
 121 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/03/">March (3)</a></li>
 122
 123 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/04/">April (3)</a></li>
 124
 125 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/05/">May (9)</a></li>
 126
 127 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/06/">June (14)</a></li>
 128
 129 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/07/">July (12)</a></li>
 130
 131 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/08/">August (13)</a></li>
 132
 133 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/09/">September (7)</a></li>
 134
 135 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/10/">October (9)</a></li>
 136
 137 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/11/">November (13)</a></li>
 138
 139 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/12/">December (12)</a></li>
 140
 141 </ul></li>
 142
 143 <li>2009
 144 <ul>
 145
 146 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/01/">January (8)</a></li>
 147
 148 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/02/">February (8)</a></li>
 149
 150 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/03/">March (12)</a></li>
 151
 152 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/04/">April (10)</a></li>
 153
 154 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/05/">May (9)</a></li>
 155
 156 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/06/">June (3)</a></li>
 157
 158 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/07/">July (4)</a></li>
 159
 160 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/08/">August (3)</a></li>
 161
 162 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/09/">September (1)</a></li>
 163
 164 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/10/">October (2)</a></li>
 165
 166 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/11/">November (3)</a></li>
 167
 168 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/12/">December (3)</a></li>
 169
 170 </ul></li>
 171
 172 <li>2008
 173 <ul>
 174
 175 <li><a href="http://people.skolelinux.org/pere/blog/archive/2008/11/">November (5)</a></li>
 176
 177 <li><a href="http://people.skolelinux.org/pere/blog/archive/2008/12/">December (7)</a></li>
 178
 179 </ul></li>
 180
 181 </ul>
 182
 183
 184
 185 <h2>Tags</h2>
 186 <ul>
 187
 188  <li><a href="http://people.skolelinux.org/pere/blog/tags/3d-printer">3d-printer (13)</a></li>
 189
 190  <li><a href="http://people.skolelinux.org/pere/blog/tags/amiga">amiga (1)</a></li>
 191
 192  <li><a href="http://people.skolelinux.org/pere/blog/tags/aros">aros (1)</a></li>
 193
 194  <li><a href="http://people.skolelinux.org/pere/blog/tags/bitcoin">bitcoin (2)</a></li>
 195
 196  <li><a href="http://people.skolelinux.org/pere/blog/tags/bootsystem">bootsystem (12)</a></li>
 197
 198  <li><a href="http://people.skolelinux.org/pere/blog/tags/bsa">bsa (2)</a></li>
 199
 200  <li><a href="http://people.skolelinux.org/pere/blog/tags/debian">debian (54)</a></li>
 201
 202  <li><a href="http://people.skolelinux.org/pere/blog/tags/debian edu">debian edu (99)</a></li>
 203
 204  <li><a href="http://people.skolelinux.org/pere/blog/tags/digistan">digistan (8)</a></li>
 205
 206  <li><a href="http://people.skolelinux.org/pere/blog/tags/english">english (124)</a></li>
 207
 208  <li><a href="http://people.skolelinux.org/pere/blog/tags/fiksgatami">fiksgatami (15)</a></li>
 209
 210  <li><a href="http://people.skolelinux.org/pere/blog/tags/fildeling">fildeling (12)</a></li>
 211
 212  <li><a href="http://people.skolelinux.org/pere/blog/tags/intervju">intervju (23)</a></li>
 213
 214  <li><a href="http://people.skolelinux.org/pere/blog/tags/kart">kart (15)</a></li>
 215
 216  <li><a href="http://people.skolelinux.org/pere/blog/tags/ldap">ldap (8)</a></li>
 217
 218  <li><a href="http://people.skolelinux.org/pere/blog/tags/lenker">lenker (4)</a></li>
 219
 220  <li><a href="http://people.skolelinux.org/pere/blog/tags/ltsp">ltsp (1)</a></li>
 221
 222  <li><a href="http://people.skolelinux.org/pere/blog/tags/multimedia">multimedia (16)</a></li>
 223
 224  <li><a href="http://people.skolelinux.org/pere/blog/tags/norsk">norsk (159)</a></li>
 225
 226  <li><a href="http://people.skolelinux.org/pere/blog/tags/nuug">nuug (123)</a></li>
 227
 228  <li><a href="http://people.skolelinux.org/pere/blog/tags/open311">open311 (2)</a></li>
 229
 230  <li><a href="http://people.skolelinux.org/pere/blog/tags/opphavsrett">opphavsrett (24)</a></li>
 231
 232  <li><a href="http://people.skolelinux.org/pere/blog/tags/personvern">personvern (47)</a></li>
 233
 234  <li><a href="http://people.skolelinux.org/pere/blog/tags/raid">raid (1)</a></li>
 235
 236  <li><a href="http://people.skolelinux.org/pere/blog/tags/reprap">reprap (11)</a></li>
 237
 238  <li><a href="http://people.skolelinux.org/pere/blog/tags/rfid">rfid (2)</a></li>
 239
 240  <li><a href="http://people.skolelinux.org/pere/blog/tags/robot">robot (4)</a></li>
 241
 242  <li><a href="http://people.skolelinux.org/pere/blog/tags/rss">rss (1)</a></li>
 243
 244  <li><a href="http://people.skolelinux.org/pere/blog/tags/ruter">ruter (4)</a></li>
 245
 246  <li><a href="http://people.skolelinux.org/pere/blog/tags/sikkerhet">sikkerhet (23)</a></li>
 247
 248  <li><a href="http://people.skolelinux.org/pere/blog/tags/sitesummary">sitesummary (4)</a></li>
 249
 250  <li><a href="http://people.skolelinux.org/pere/blog/tags/standard">standard (26)</a></li>
 251
 252  <li><a href="http://people.skolelinux.org/pere/blog/tags/stavekontroll">stavekontroll (1)</a></li>
 253
 254  <li><a href="http://people.skolelinux.org/pere/blog/tags/stortinget">stortinget (4)</a></li>
 255
 256  <li><a href="http://people.skolelinux.org/pere/blog/tags/surveillance">surveillance (9)</a></li>
 257
 258  <li><a href="http://people.skolelinux.org/pere/blog/tags/valg">valg (6)</a></li>
 259
 260  <li><a href="http://people.skolelinux.org/pere/blog/tags/video">video (25)</a></li>
 261
 262  <li><a href="http://people.skolelinux.org/pere/blog/tags/vitenskap">vitenskap (1)</a></li>
 263
 264  <li><a href="http://people.skolelinux.org/pere/blog/tags/web">web (19)</a></li>
 265
 266 </ul>
 267
 268
 269     </div>
 270     <p style="text-align: right">
 271  Created by <a href="http://steve.org.uk/Software/chronicle">Chronicle v4.4</a>
 272 </p>
 273
 274   </body>
 275 </html>