blog/Idea_for_storing_LTSP_configuration_in_LDAP.html

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   5   <title>Petter Reinholdtsen: Idea for storing LTSP configuration in LDAP</title>
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  11   <h1>
  12        <a href="http://people.skolelinux.org/pere/blog/">Petter Reinholdtsen</a>
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  20   <div class="title">Idea for storing LTSP configuration in LDAP</div>
  21   <div class="date">2010-07-11 22:00</div>
  22   <div class="body">
  23 <p>Vagrant mentioned on IRC today that ltsp_config now support
  24 sourcing files from /usr/share/ltsp/ltsp_config.d/ on the thin
  25 clients, and that this can be used to fetch configuration from LDAP if
  26 Debian Edu choose to store configuration there.</p>
  27
  28 <p>Armed with this information, I got inspired and wrote a test module
  29 to get configuration from LDAP.  The idea is to look up the MAC
  30 address of the client in LDAP, and look for attributes on the form
  31 ltspconfigsetting=value, and use this to export SETTING=value to the
  32 LTSP clients.</p>
  33
  34 <p>The goal is to be able to store the LTSP configuration attributes
  35 in a "computer" LDAP object used by both DNS and DHCP, and thus
  36 allowing us to store all information about a computer in one place.</p>
  37
  38 <p>This is a untested draft implementation, and I welcome feedback on
  39 this approach.  A real LDAP schema for the ltspClientAux objectclass
  40 need to be written.  Comments, suggestions, etc?</p>
  41
  42 <blockquote><pre>
  43 # Store in /opt/ltsp/$arch/usr/share/ltsp/ltsp_config.d/ldap-config
  44 #
  45 # Fetch LTSP client settings from LDAP based on MAC address
  46 #
  47 # Uses ethernet address as stored in the dhcpHost objectclass using
  48 # the dhcpHWAddress attribute or ethernet address stored in the
  49 # ieee802Device objectclass with the macAddress attribute.
  50 #
  51 # This module is written to be schema agnostic, and only depend on the
  52 # existence of attribute names.
  53 #
  54 # The LTSP configuration variables are saved directly using a
  55 # ltspConfig prefix and uppercasing the rest of the attribute name.
  56 # To set the SERVER variable, set the ltspConfigServer attribute.
  57 #
  58 # Some LDAP schema should be created with all the relevant
  59 # configuration settings.  Something like this should work:
  60 #
  61 # objectclass ( 1.1.2.2 NAME 'ltspClientAux'
  62 #     SUP top
  63 #     AUXILIARY
  64 #     MAY ( ltspConfigServer $ ltsConfigSound $ ... )
  65
  66 LDAPSERVER=$(debian-edu-ldapserver)
  67 if [ "$LDAPSERVER" ] ; then
  68     LDAPBASE=$(debian-edu-ldapserver -b)
  69     for MAC in $(LANG=C ifconfig |grep -i hwaddr| awk '{print $5}'|sort -u) ; do
  70         filter="(|(dhcpHWAddress=ethernet $MAC)(macAddress=$MAC))"
  71         ldapsearch -h "$LDAPSERVER" -b "$LDAPBASE" -v -x "$filter" | \
  72             grep '^ltspConfig' | while read attr value ; do
  73             # Remove prefix and convert to upper case
  74             attr=$(echo $attr | sed 's/^ltspConfig//i' | tr a-z A-Z)
  75             # bass value on to clients
  76             eval "$attr=$value; export $attr"
  77         done
  78     done
  79 fi
  80 </pre></blockquote>
  81
  82 <p>I'm not sure this shell construction will work, because I suspect
  83 the while block might end up in a subshell causing the variables set
  84 there to not show up in ltsp-config, but if that is the case I am sure
  85 the code can be restructured to make sure the variables are passed on.
  86 I expect that can be solved with some testing. :)</p>
  87
  88 <p>If you want to help out with implementing this for Debian Edu,
  89 please contact us on debian-edu@lists.debian.org.</p>
  90
  91 <p>Update 2010-07-17: I am aware of another effort to store LTSP
  92 configuration in LDAP that was created around year 2000 by
  93 <a href="http://www.pcxperience.com/thinclient/documentation/ldap.html">PC
  94 Xperience, Inc., 2000</a>.  I found its
  95 <a href="http://people.redhat.com/alikins/ltsp/ldap/">files</a> on a
  96 personal home page over at redhat.com.</p>
  97 </div>
  98
  99   <div class="tags">Tags: <a href="http://people.skolelinux.org/pere/blog/tags/debian">debian</a>, <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>, <a href="http://people.skolelinux.org/pere/blog/tags/ldap">ldap</a>, <a href="http://people.skolelinux.org/pere/blog/tags/nuug">nuug</a>.</div>
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