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1<!-- $Id$ -->
4  <title id="installation">Installation</title>
6  <para>Last modified on $Date$</para>
8  <para>
9    Before being able to use <application>PyKota</application>, you have of course to
10    install it first. But before installing, you must carefully plan your installation.
11  </para>
13  <para>
14    First you have to determine which machine will be the <application>PyKota</application>
15    <firstterm>Storage Server</firstterm>. The Storage Server is the host responsible
16    for keeping a centralized database of print usage for all your printers, users and groups.
17  </para>
19  <para>
20    Then you have to list all the <firstterm>Print Servers</firstterm> for which
21    you plan to use <firstterm>print quota</firstterm> facilities.
22  </para>
24  <para>
25    Finally you have to download <application>PyKota</application>'s latest version
26    or buy an official package, from
27    <ulink url=""></ulink>.
28    If you've just bought an official package, then as soon as you've receive it you
29    have to decompress and visit its archive, to do so just type the following commands :
30    <screen>
31jerome@nordine:~$ tar -zxf pykota-1.24_official.tar.gz   
32jerome@nordine:~$ cd pykota-1.24_official
34    </screen>
35  </para>
37  <para>
38    You can see many files in this directory, the first ones to read are <filename>README</filename>,
39    then <filename>COPYING</filename> and <filename>LICENSE</filename>. They will give you
40    basic installation instructions and explain the licensing terms under which
41    <application>PyKota</application> is distributed. Of course they are also mostly
42    boring to read ! Detailed installation and operating instructions are defined
43    in the <filename>./docs</filename> directory, in the form of <acronym>SGML</acronym>
44    documentation in the <ulink url="">DocBook</ulink> format.
45    You have to compile these files into readable documentation like the <acronym>HTML</acronym>
46    or <acronym>PDF</acronym> formats, or buy an official <application>PyKota</application> package
47    which already contains these compiled forms of the documentation. Of course you already
48    know this because that's what you are currently reading !
49  </para>
51  <para>
52    Now we will see what has to be done on each of the servers we are planning to use.
53    <note>
54      <title>Note</title>
55      <para>
56        Of course, depending on the size of your network, you may very well
57        use the same machine as both a Print Server and a Storage Server.
58        This is especially the case if you've got only one server.
59      </para>
60    </note> 
61  </para>
63  <sect1>
64    <title>Storage Server Installation</title>
66    <para>
67      Depending on <application>PyKota</application>'s version number, different
68      types of storage backends may be supported, so we will see for each one of
69      them how to configure it.
70    </para>
72    <sect2>
73      <title>PostgreSQL</title>
75      <para>
76        <application>PostgreSQL</application> is an <firstterm>Object Relationnal DataBase
77        Management System</firstterm> distributed under a <firstterm>Free Software</firstterm>
78        license from the
79        <ulink url=""></ulink>
80        web site. It certainely is the free <acronym>RDBMS</acronym> which has the most advanced
81        features, and is widely used all over the world.
82      </para>
84      <para>
85        To configure your Storage Server, you must have PostgreSQL already working.
86        The complete installation of <application>PostgreSQL</application> is not covered by
87        the present manual, please refer to your system's documentation or to
88        <ulink url=""></ulink> for
89        details.
90      </para>
92      <para>
93        One thing you have to check, though, is that every Print Server on which you
94        want to install the print quota mechanism, must be able to connect to the
95        <application>PostgreSQL</application> server. In the default installation of
96        <application>PostgreSQL</application> this may not be the case for security reasons, except if both
97        servers are in fact the same machine. In any case, it is recommended that you
98        check the <filename>/etc/postgresql/pg_hba.conf</filename> file and modify it if
99        needed. This file is self documented and its modification is straightforward.
100        You also have to make sure that <application>PostgreSQL</application> accepts <acronym>TCP/IP</acronym> connections.
101        To do so you either have to launch it with the <option>-i</option> option or
102        modify the <filename>/etc/postgresql/postgresql.conf</filename> file, which is
103        self documented and easy to modify too. Allowing <acronym>TCP/IP</acronym> connections
104        is not necessary though if your Quota Storage Server and your Print Server are
105        the very same host.
106      </para> 
108      <para>
109        Here's an excerpt from a <filename>pg_hba.conf</filename> file. This one rejects all
110        connections to PyKota's database excepted when made from the same host by <application>PostgreSQL</application> users
111        <literal>pykotauser</literal> or <literal>pykotaadmin</literal> with the correct password.
113        local all    postgres                              ident sameuser
114        local all    all                                   reject
115        host  pykota pykotauser crypt
116        host  pykota pykotaadmin crypt
117        host  pykota all reject
119     </para>
121     <para>
122        Of course if your print server and your database servers have different <acronym>IP</acronym>
123        addresses, you have to replace the <literal></literal> address above with your print
124        server's <acronym>IP</acronym> address. As an alternative, you could still keep these
125        lines and add similar lines with other <acronym>IP</acronym> addresses if you have several
126        print servers for which you want a single centralized database.
127        <tip>
128          <title>Tip</title>
129          <para>
130            Don't forget to restart <application>PostgreSQL</application> if you modify
131            any of its configuration files, in order for the changes to take effect.
132          </para>
133        </tip> 
134      </para>
136      <para>
137        Be careful, you may be unable to connect from a Print Server to the <application>PostgreSQL</application>
138        server even if the configuration is correct. Sometimes your connections may be blocked by
139        one or more network firewalls along the route from one machine to the other. If this
140        is the case, then the best thing you can do is to ask your <firstterm>Network Administrator</firstterm>
141        to not filter the IP port used by <application>PostgreSQL</application>, which is
142        usually port <literal>5432/tcp</literal>.
143        <note>
144          <title>Note</title>
145          <para>
146            The TCP/IP network port used by PostgreSQL may be different. When in doubt, ask your
147            <firstterm>System Administrator</firstterm> for the correct value.
148          </para>
149        </note> 
150      </para>
152      <para>
153        Now that your <application>PostgreSQL</application> server is up and running, and
154        is waiting for your connections, you have to create the Quota Storage DataBase.
155        To do so, you'll have to feed <application>PostgreSQL</application> with the
156        <filename>pykota-1.24/initscripts/postgresql/pykota-postgresql.sql</filename> file.
157        This file will create a Quota DataBase administrator in the <application>PostgreSQL</application> system, then create an empty
158        Quota DataBase and set some permissions on it. The Quota DataBase administrator
159        is the <application>PostgreSQL</application>'s user used to manage the Quota database.
160        The Quota DataBase Administrator is not present in the Quota Database
161        itself, he is only defined in <application>PostgreSQL</application> and don't
162        have to exist on any system, nor in the Quota DataBase. His default name
163        is <literal>pykotaadmin</literal>.
164        A Quota Storage read-only user is also created under the name of <literal>pykotauser</literal>.
165        This read-only user is used by <application>PyKota</application> to connect to the
166        Quota Storage when an user who is not a <application>PyKota</application> administrator
167        <footnote><para>a <application>PyKota</application> administrator is an user who can read the <filename>~pykota/pykotadmin.conf</filename> file.</para></footnote>
168        launches a pykota command. This prevents normal
169        users from being able to modify their own, or other users', quota information.
170        The database which will be created will be named <literal>pykota</literal> by default.
171        <note>
172          <title>Note</title>
173          <para>
174            You can choose other names if you want, just modify the
175            <filename>initscripts/postgresql/pykota-postgresql.sql</filename> file
176            accordingly, and report your changes into <application>PyKota</application>'s
177            configuration files.
178          </para>
179        </note> 
180      </para>
182      <para>
183        To run this script, you can use the <command>psql</command> frontend to
184        <application>PostgreSQL</application>, but your priviledges must be sufficient
185        to be allowed to create users and databases. You can launch <command>psql</command>
186        as the <literal>postgres</literal> user which is <application>PostgreSQL</application>'s
187        default administrator, and connect to the default database named <literal>template1</literal>.
188        From a command line interpreter (i.e. shell), type the following commands :
189        <screen>
190jerome@nordine:~$ cd pykota-1.24_official/initscripts/postgresql
191jerome@nordine:~/pykota-1.24_official/initscripts$ psql -h localhost -U postgres template1
192Welcome to psql, the PostgreSQL interactive terminal.
194Type:  \copyright for distribution terms
195       \h for help with SQL commands
196       \? for help on internal slash commands
197       \g or terminate with semicolon to execute query
198       \q to quit
200template1=# \i pykota-postgresql.sql
201            ... a lot of output lines
203        </screen>
204        <note>
205          <title>Note</title>
206          <para>
207            If you use RPM or DEB packages, usually the
208            <filename>pykota-postgresql.sql</filename> file gets installed into the
209            <filename>/usr/share/pykota/postgresql</filename> directory, along
210            with a README file.
211          </para>
212        </note> 
213      </para>
215      <para>
216        For security reasons, you may want to set passwords in
217        <application>PostgreSQL</application> for the
218        <literal>pykotaadmin</literal> and <literal>pykotauser</literal> users.
219        Otherwise any user able to connect to
220        <application>PostgreSQL</application> on your Quota Storage Server
221        could connect to the quota database, and either see it, or even modify it without problem.
222      </para>
224      <para>
225        To do so, just type the following lines while still being at the <command>psql</command>
226        prompt (replace the password values by your own, and do the same for the <literal>pykotauser</literal> user) :
227        <screen>
228pykota=# ALTER USER pykotaadmin PASSWORD 'somepassword';
230pykota=# \q
232        </screen>
233      </para>
235      <para>
236        The <literal>\q</literal> command above will quit the <command>psql</command>
237        program and return you to the shell's command line prompt.
238      </para>
240      <para>
241        To improve security further, you could encrypt your database connections, or
242        take any other step as needed. Please refer to <application>PostgreSQL</application>'s
243        documentation for details.
244        <warning>
245          <title>Warning</title>
246          <para>
247            Defining passwords may not be sufficient if your database access rule is
248            set to <literal>trust</literal> in the <filename>/etc/postgresql/pg_hba.conf</filename>.
249            Again, please refer to <application>PostgreSQL</application>'s documentation
250            for details. Also, passwords will fly unencrypted over the network by default,
251            so be sure to take any necessary step to secure your database server from
252            unauthorized use. This has nothing to do with <application>PyKota</application>
253            though, it is just a general rule to keep in mind.
254          </para>
255        </warning> 
256      </para>
258      <para>
259        If no error occured, then your Quota DataBase is ready to be used.
260        Now you can let the Quota Storage Server alone, the remaining work
261        will have to be done on each one of the print servers which will
262        use this particular Quota Storage Server.
263        <tip>
264          <title>Tip</title>
265          <para>
266            If an error occured, maybe your PostgreSQL version is too old, or
267            an unexpected problem (like a bug) happened. Please contact us via email so that we
268            can try to fix the problem. Thanks in advance.
269          </para>
270        </tip> 
271      </para>
273    </sect2> 
275    <sect2>
276      <title>LDAP</title>
278      <para>
279        Any <acronym>LDAP</acronym> server, and particularly <application>OpenLDAP</application>, can be used
280        as a Quota Storage Backend.
281        Some other LDAP servers can be used, but this is currently untested in production.
282      </para>
284      <para>
285        <application>OpenLDAP</application> is a Lightweight Directory Access Protocol server
286        implementation published as Free Software.
287        You can download it from <ulink url=""></ulink>.
288      </para>
290      <para>
291        To use <application>OpenLDAP</application> as your Quota Storage Backend, you have to copy the
292        <filename>pykota/initscripts/ldap/pykota.schema</filename> into <application>OpenLDAP</application>'s
293        schemas directory.
294        Under Debian GNU/Linux, this is something like :
295        <screen>       
296$ cp pykota.schema /etc/ldap/schema
297        </screen>
298        <note>
299          <title>Note</title>
300          <para>
301            If you use RPM or DEB packages, the
302            <filename>pykota.schema</filename> file is usually installed into the
303            <filename>/usr/share/pykota/ldap</filename> directory, along
304            with a README file, and may also be installed automatically in
305            your <acronym>LDAP</acronym> server's schemas directory.
306          </para>
307        </note> 
308     </para>
309     <para>   
310       Then edit <filename>/etc/ldap/slapd.conf</filename> and add a line to   
311       include the PyKota schema. You should have something
312       like :
313       <screen>   
314# Schema and objectClass definitions
315include         /etc/ldap/schema/core.schema
316include         /etc/ldap/schema/cosine.schema
317include         /etc/ldap/schema/nis.schema
318include         /etc/ldap/schema/inetorgperson.schema
319include         /etc/ldap/schema/pykota.schema
320        </screen>       
321      </para>
323      <para>
324        While this is not mandatory, it is recommended that you setup
325        some indexes for some often accessed PyKota attributes.
326        Here are the minimal indexes
327        lines you may want to put in <filename>slapd.conf</filename> :
328        <screen>
329# Indexes for PyKota
330index pykotaUserName pres,eq,sub
331index pykotaGroupName pres,eq,sub
332index pykotaPrinterName pres,eq,sub
333index pykotaBillingCode pres,eq,sub
334index pykotaLastJobIdent eq
335        </screen>
336      </para>
338      <para>
339        Now you must ensure that the DNs you'll use to bind to   
340        your OpenLDAP server don't have search queries size limits,
341        which gives for example (OpenLDAP 2.1.x or above) :
344# No Limits for PyKota's administrator and read-only user
345limits dn="cn=pykotaadmin,dc=example,dc=com" size.soft=-1 size.hard=soft
346limits dn="cn=pykotauser,dc=example,dc=com" size.soft=-1 size.hard=soft
349        Where pykotaadmin and pykotauser are the usernames used to bind to your
350        OpenLDAP server within PyKota, respectively in ReadWrite mode
351        (as set in pykotadmin.conf) and in ReadOnly mode (as set in pykota.conf).
352      </para>
354      <para>
355        Finally, stop the <application>OpenLDAP</application> server, generate
356        the index files, and restart <application>OpenLDAP</application>
357        <screen>   
358$ /etc/init.d/slapd stop
359$ slapindex
360$ /etc/init.d/slapd start
361        </screen>
362      </para>
364      <para>
365        With an <acronym>LDAP</acronym> backend, PyKota will need some branches
366        in your <acronym>LDAP</acronym> directory to put its own datas.
367        You can configure PyKota to either attach its datas to your existing
368        users and groups, or to put them in their own <literal>ou</literal>.
369        But some <literal>ou</literal>s dedicated to PyKota are needed in any case,
370        so the best bet may be to put all PyKota's datas below an <literal>ou=PyKota</literal>
371        branch. While this will separate these datas from your existing users and groups
372        entries, this may ease the maintainance.
373      </para>
375      <para>
376        PyKota needs at least an <literal>ou</literal> for printers, for users quotas, for
377        groups quotas, for print jobs, for billing codes, and for pointers to the last job of each printer.
378        In the future, this last <literal>ou</literal> may disappear as its content
379        will probably be attached to each printer.
380      </para>
382      <para>
383        Actually PyKota doesn't create these <literal>ou</literal>s for you, because it's
384        difficult to guess what is the best configuration for you. So you have to
385        create them by yourself, either directly with a text editor and the
386        <command>ldapadd</command> command, or with some specialized tool
387        like <command>gq</command>. You can look at the <filename>initscripts/ldap/pykota-sample.ldif</filename>
388        file to see which minimal branches are necessary.
389        <note>
390          <title>Note</title>
391          <para>
392            If you use RPM or DEB packages, usually the
393            <filename>pykota-sample.ldif</filename> file is installed into the
394            <filename>/usr/share/pykota/ldap</filename> directory, along
395            with a README file.
396          </para>
397        </note> 
398      </para>
400      <para>
401        If no error occured, then your Quota DataBase is ready to be used.
402        Now you can let the Quota Storage Server alone, the remaining work
403        will have to be done on each one of the print servers which will
404        use this particular Quota Storage Server.
405        <tip>
406          <title>Tip</title>
407          <para>
408            If an error occured, maybe your OpenLDAP version is too old, or
409            an unexpected problem (like a bug) happened. Please contact us via email so that we
410            can try to fix the problem. Thanks in advance.
411          </para>
412        </tip> 
413      </para>
414    </sect2> 
416    <sect2>
417      <title>MySQL</title>
419      <para>
420        <application>MySQL</application> is supported but not documented for now.
421      </para>
422    </sect2> 
424    <sect2>
425      <title>SQLite</title>
427      <para>
428        <application>SQLite</application> is supported but not documented for now.
429      </para>
430    </sect2> 
432    <sect2>
433      <title>Berkeley DB</title>
435      <para>
436        A <application>Berkeley DB</application> Storage Backend is planned, but it actually
437        doesn't exist. It seems that remote storage won't be possible with such a backend,
438        so in other terms this means that you will have a different quota database on
439        each print server. This may still prove to be useful for small configurations.
440      </para>
441    </sect2> 
442  </sect1> 
444  <sect1>
445    <title>Print Server Installation</title>
447    <para>
448      For each Print Server on which you plan to implement the print quota
449      mechanism, you have, of course, to have an already working printing environment.
450      Currently <application>PyKota</application> works with
451      <ulink url=""><application>CUPS</application></ulink>
452      but older releases also supported <ulink url=""><application>LPRng</application></ulink>.
453      <application>LPRng</application> support might be re-added in the future.
454    </para>
456    <para>
457      Here's the list of software you have to install on each Print Server, version numbers
458      are given as an indication of which was successfully tested, but older versions may
459      work too.
460      <itemizedlist>
461        <listitem>
462          <para>
463            <application>CUPS</application> version 1.1.14 or above.
464            You can download it from <ulink url=""></ulink>
465          </para>
466        </listitem> 
467        <listitem>
468          <para>
469            <application>Python</application> version 2.2 or above.
470            You can download it from <ulink url=""></ulink>.
471            While <application>PyKota</application> itself will try to preserve compatibility
472            with <application>Python</application> version 2.2 for the near future, some <application>Python</application>
473            modules which are needed by <application>PyKota</application> may require a more recent version
474            of this language.
475          </para>
476        </listitem> 
477        <listitem>
478          <para>
479            Quota Storage client libraries, depending on your Quota Storage Backend :
480            <itemizedlist>
481              <listitem>
482                <para>
483                  PostgreSQL backend :
484                  <itemizedlist>
485                    <listitem>
486                      <para>
487                        <application>PostgreSQL</application> client libraries. They must match the <application>PostgreSQL</application>
488                        version used on your Quota Storage Server.
489                      </para>
490                    </listitem> 
491                    <listitem>
492                      <para>
493                        The <application>PygreSQL</application> python module.
494                        It must have been compiled against the same
495                        <application>PostgreSQL</application> client libraries.
496                        <application>PygreSQL</application> is normally included in
497                        <application>PostgreSQL</application>, but you may want to
498                        download it from <ulink url=""></ulink>
499                      </para>
500                    </listitem> 
501                  </itemizedlist> 
502                </para>
503              </listitem> 
504              <listitem>
505                <para>
506                  OpenLDAP backend :
507                  <itemizedlist>
508                    <listitem>
509                      <para>
510                        <application>OpenLDAP</application> client libraries. They must match
511                        the <application>OpenLDAP</application> version used on your Quota Storage Server.
512                      </para>
513                    </listitem> 
514                    <listitem>
515                      <para>
516                        The <application>Python-LDAP</application> python module.
517                        It must have been compiled against the same
518                        <application>OpenLDAP</application> client libraries.
519                        You may download this module from <ulink url=""></ulink>
520                      </para>
521                    </listitem> 
522                  </itemizedlist>
523                </para>
524              </listitem>
525              <listitem>
526                <para>
527                  MySQL backend : Supported but not documented yet.
528                </para>
529              </listitem>
530              <listitem>
531                <para>
532                  SQLite backend : Supported but not documented yet.
533                </para>
534              </listitem>
535              <listitem>
536                <para>
537                  Berkeley DB backend : Not supported yet.
538                </para>
539              </listitem>
540            </itemizedlist> 
541          </para>
542        </listitem> 
543        <listitem>
544          <para>
545            <application>ucd-snmp</application> or <application>net-snmp</application> tools, version 4.2.5 or above. You only need
546            the <command>snmpget</command> command.
547            You can download this software from <ulink url=""></ulink>.
548            You only need this if you plan to query your printers for their internal page counter via SNMP.
549          </para>
550        </listitem> 
551        <listitem>
552          <para>
553            <application>netatalk</application> version 1.6.1 or above. You only need
554            the <command>pap</command> command.
555            You can download this software from <ulink url=""></ulink>.
556            You only need this if you plan to query your printers for their internal page counter via AppleTalk.
557          </para>
558        </listitem> 
559        <listitem>
560          <para>
561            eGenix' mxDateTime Python module version 2.0.3 or above. It must match your default Python version.
562            You can download it from <ulink url=""></ulink>.
563          </para>
564        </listitem> 
565        <listitem>
566          <para>
567            The Python acccelerator <application>Psyco</application>. It must match your default Python version.
568            You can download it from <ulink url=""></ulink>.
569            You only need this if you run on the <literal>x86</literal> architecture because
570            <application>Psyco</application> doesn't yet exist on other architectures.
571          </para>
572        </listitem> 
573        <listitem>
574          <para>
575            The <application>pysnmp</application> Python module version 3.4.2, 3.4.3 or 3.4.4 exclusively.
576            You can download it from <ulink url=""></ulink>.
577          </para>
578        </listitem> 
579        <listitem>
580          <para>
581            The <application>JAXML</application> Python module.
582            You can download it from <ulink url=""></ulink>.
583          </para>
584        </listitem> 
585        <listitem>
586          <para>
587            The <application>ReportLab</application> Toolkit Python module.
588            You can download it from <ulink url=""></ulink>.
589          </para>
590        </listitem> 
591        <listitem>
592          <para>
593            The <application>Python Imaging Library - PIL</application> module.
594            You can download it from <ulink url=""></ulink>.
595          </para>
596        </listitem> 
597        <listitem>
598          <para>
599            The <application>PyOSD</application> Python module.
600            You can download it from <ulink url=""></ulink>.
601          </para>
602        </listitem> 
603        <listitem>
604          <para>
605            The <application>pkpgcounter</application> Generic Page Description Language parser.
606            You can download it from <ulink url=""></ulink>.
607          </para>
608        </listitem> 
609        <listitem>
610          <para>
611            The <application>PyPAM</application> Python interface to <acronym>PAM</acronym>.
612            You'll need this if you plan to ask users to authenticate when printing through <command>pknotify</command>
613            and <command>pykoticon</command>. You don't need this module otherwise.
614            If needed, you can download it from <ulink url=""></ulink>.
615          </para>
616        </listitem> 
617      </itemizedlist> 
618    </para>
620    <para>
621      Instead of downloading all these programs' sources and compiling them, which really
622      is a boring task considering that many software are needed, you may prefer to look
623      into the packages included with your GNU/Linux distribution of choice (if you use
624      this operating system of course). Most, if not all, GNU/Linux distributions include
625      all the software mentionned above, in the form of packages which are easier to
626      install than sources tarballs. This is probably the same for the many *BSD
627      distributions.
628    </para>
630    <para>
631       You can check that all needed software is installed by launching the <command></command>
632       command :
633      <screen>     
634$ python     
635      </screen>
636    </para>
638    <para>
639      Once all these software are installed, installing PyKota itself is a breeze.
640      PyKota being written entirely in the Python language, which is interpreted,
641      there's no need to compile anything. You just have to execute the installation
642      script :
643      <screen>     
644$ python install     
645      </screen>
646    </para>
648    <para>
649      The setup script will automatically create the
650      <filename>/usr/share/pykota/conf</filename> directory and put the sample
651      configuration files <filename>conf/pykota.conf.sample</filename> and
652      <filename>conf/pykotadmin.conf.sample</filename> there, along with
653      a <filename>README</filename> file explaining their purpose.
654    </para>
656    <para>
657      Now you have to create a <literal>pykota</literal> system user and group. The <application>PyKota</application>
658      software will automatically search its configuration files in user <literal>pykota</literal>'s
659      home directory. For example we could create the user and group, and set <filename>/etc/pykota</filename>
660      as the home directory, but any other home directory will do :
662    adduser --system --group --home /etc/pykota --gecos PyKota pykota
664    </para>
666    <para>
667      You now have to copy the sample configuration files into the <filename>~pykota</filename>
668      directory, under the respective names <filename>pykota.conf</filename> and
669      <filename>pykotadmin.conf</filename>. Once copied there, you just
670      have to modify these files to adapt them to your own setup.
671      These files are heavily commented, so you should have no problem.
672      Also their format is quite common, because it's the one used by
673      <application>Samba</application> for example, or by <literal>.ini</literal>
674      files under <application>MS-Windows</application>, so you may already
675      be familiar with this syntax.
676      In a future release, this documentation will include the complete
677      reference for all configuration fields available. Keep in mind that
678      <application>PyKota</application> can be really heavily customized, and can delegate some work
679      to any external command of your choice.
680    </para>
682    <para>
683      Please create a backup copy of the <filename>~pykota</filename>
684      directory before modifying a working installation.
685    </para>
687    <para>
688      PyKota features some interesting possibilities which allow you to
689      define options either globally so that they apply to all printers,
690      or on a per printer basis. Please see the sample configuration files
691      to see what I mean. In the simplest form, only a <literal>[global]</literal> section is
692      needed. In more complex configurations, you will have to create
693      one section per printer. Each section in the configuration files
694      begins with a name between square brackets <literal>[]</literal>.
695      The name to use to define a particular printer section is the name
696      of the print queue you want to manage with PyKota.
697    </para>
699    <para>
700      After you have modified <application>PyKota</application>'s configuration files, you have to
701      double check their permissions, otherwise your installation may be
702      insecure or may not work at all.
703      The main configuration file <filename>~pykota/pykota.conf</filename>
704      doesn't contain much sensitive information, so it can be made
705      readable by anyone. If normal users read this file, at best they
706      will learn the username and optional password of the read-only
707      database user. This means that beside being allowed to read all the contents of
708      the quota database, they won't be allowed to modify or delete it.
709      On the other hand, the <filename>~pykota/pykotadmin.conf</filename>
710      file contains the read-write user's identity and password. You must then
711      ensure that no normal user can read this file. It should only be readable
712      by the <literal>root</literal> user, which is always the case, and by
713      <application>PyKota</application> administrators. In addition,
714      users for which <application>CUPS</application> doesn't run as user <literal>root</literal> will
715      have to ensure that the user their printing system is run as
716      can read both of these files. An easy way to do so is to put the <literal>lp</literal> user
717      (for example) into the <literal>pykota</literal> system group, then
718      to give the correct permissions to <application>PyKota</application>'s configuration files :
719      <screen>
720$ chown pykota.pykota ~pykota/pykota.conf     
721$ chmod 644 ~pykota/pykota.conf     
722$ chown pykota.pykota ~pykota/pykotadmin.conf     
723$ chmod 640 ~pykota/pykotadmin.conf     
724      </screen>
726      <warning>
727        <title>Warning</title>
728        <para>
729          All the users allowed to read the <filename>~pykota/pykotadmin.conf</filename>
730          are considered to be <application>PyKota</application> administrators. So be
731          careful with these files permissions.
732        </para>
733      </warning>
734    </para>
736    <para>
737      On some systems, you may be able to strenghten permissions like this :
738      <screen>
739$ chown pykota.pykota ~pykota/pykota.conf     
740$ chmod 640 ~pykota/pykota.conf     
741$ chown pykota.pykota ~pykota/pykotadmin.conf     
742$ chmod 600 ~pykota/pykotadmin.conf     
743      </screen>
744    </para>
746    <para>
747      And on other ones, you may need to relax them, and change the files' owner :
748      <screen>
749$ chown lp.pykota ~pykota/pykota.conf     
750$ chmod 640 ~pykota/pykota.conf     
751$ chown lp.pykota ~pykota/pykotadmin.conf     
752$ chmod 640 ~pykota/pykotadmin.conf     
753      </screen>
754    </para>
756    <para>
757      This all depends on the printing system you are using, and the user the
758      printing system is usually running as. You need to remember three things :
760      <itemizedlist>
761        <listitem>
762          <para>
763            The user your printing system runs as MUST be allowed to read
764            both <application>PyKota</application>'s configuration files.
765          </para> 
766        </listitem> 
767        <listitem>       
768          <para>
769            Any user who can read <filename>pykotadmin.conf</filename>
770            is a <application>PyKota</application> administrator, and
771            can do whatever he wants to the print quota database.
772          </para>
773        </listitem>
774        <listitem>       
775          <para>
776            If <filename>cupsd.conf</filename> contains <literal>RunAsUser</literal>, then
777            you won't be able to authenticate users with <command>pknotify</command> and <command>pykoticon</command>.
778            Also in this case you may have to make <application>PyKota</application>'s configuration files
779            owned by the user <application>CUPS</application> runs as.
780          </para>
781        </listitem>
782      </itemizedlist> 
783    </para>
785    <para>
786      Don't forget to restart your print server sofware if you changed group membership for the user it runs
787      as, otherwise your change wouldn't be taken into account.
788    </para>
790    <para>
791      Now depending on your printing system, the configuration to do is particular.
792      We will now see how to plug PyKota into <application>CUPS</application> since <application>LPRng</application>
793      is not supported anymore.
794    </para>
796    <sect2>
797      <title>With CUPS</title>
799      <para>
800        From version 1.16alpha7 on, configuring <application>PyKota</application> to integrate
801        within <application>CUPS</application> is more than easy.
802      </para>
804      <para>
805        You just have to create a symbolic link to the <command>cupspykota</command>
806        command in <application>CUPS</application>' backend directory :
807        <screen>       
808$ cd /usr/lib/cups/backend       
809$ ln -s /usr/share/pykota/cupspykota cupspykota
810        </screen>
811      </para>
813      <para>
814        You have to restart <application>CUPS</application> for this modification to
815        take effect :
816        <screen>
817$ /etc/init.d/cupsys restart       
818        </screen>
819      </para>
821      <para>
822        Now point your web browser to CUPS configuration page, usually at
823        <ulink url="http://localhost:631">http://localhost:631</ulink> on
824        your print server.
825      </para>
827      <para>
828        Then when creating new printers or reconfiguring existing ones, just
829        choose devices which are <literal>PyKota managed</literal>
830        <footnote>
831          <para>
832            Debian 3.0 Woody is known to have problems : CUPS 1.1.14 doesn't automatically
833            detect <literal>PyKota managed</literal> devices. So you have to manually
834            modify CUPS' <filename>printers.conf</filename> file as explained in
835            PyKota's toplevel <filename>README</filename> file.
836          </para>
837        </footnote>
838        instead of
839        normal devices. You've got one <literal>PyKota managed</literal> device
840        for each regular device available from CUPS, so just choose the appropriate
841        one.
842      </para>
844      <para>
845        Repeat the above procedure for each print queue on which you want to use
846        PyKota. That's all !
847      </para>
849      <sect3>
850        <title>Troubleshooting</title>
851        <para>
852          In case of problem, the simplest way to solve it is currently
853          to ask on PyKota's mailing list, describing the symptoms, as
854          well as the hardware and software you use.
855        </para>
857        <para>
858          A searchable FAQ is now available at
859          <ulink url=""></ulink>.
860          A FAQ entry explaining in great details how to diagnose a problem correctly is
861          available at
862          <ulink url=""></ulink>.
863        </para>
865        <para>
866          You can now ask questions on IRC :
867          <screen>
869/join #pykota
870          </screen>
871        </para> 
872      </sect3> 
874    </sect2>
876  </sect1> 
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