Last modified on $Date$ Before being able to use PyKota, you have of course to install it first. But before installing, you must carefully plan your installation. First you have to determine which machine will be the PyKota Storage Server. The Storage Server is the host responsible for keeping a centralized database of print usage for all your printers, users and groups. Then you have to list all the Print Servers for which you plan to use print quota facilities. Finally you have to download PyKota's latest version or buy an official package, from http://www.librelogiciel.com/software/. If you've just bought an official package, then as soon as you've receive it you have to decompress and visit its archive, to do so just type the following commands : jerome@nordine:~$ tar -zxf pykota-1.23_official.tar.gz jerome@nordine:~$ cd pykota-1.23_official jerome@nordine:~/pykota-1.23_official$ You can see many files in this directory, the first ones to read are README, then COPYING and LICENSE. They will give you basic installation instructions and explain the licensing terms under which PyKota is distributed. Of course they are also mostly boring to read ! Detailed installation and operating instructions are defined in the ./docs directory, in the form of SGML documentation in the DocBook format. You have to compile these files into readable documentation like the HTML or PDF formats, or buy an official PyKota package which already contains these compiled forms of the documentation. Of course you already know this because that's what you are currently reading ! Now we will see what has to be done on each of the servers we are planning to use. Of course, depending on the size of your network, you may very well use the same machine as both a Print Server and a Storage Server. This is especially the case if you've got only one server. Depending on PyKota's version number, different types of storage backends may be supported, so we will see for each one of them how to configure it. PostgreSQL is an Object Relationnal DataBase Management System distributed under a Free Software license from the http://www.postgresql.org web site. It certainely is the free RDBMS which has the most advanced features, and is widely used all over the world. To configure your Storage Server, you must have PostgreSQL already working. The complete installation of PostgreSQL is not covered by the present manual, please refer to your system's documentation or to http://www.postgresql.org for details. One thing you have to check, though, is that every Print Server on which you want to install the print quota mechanism, must be able to connect to the PostgreSQL server. In the default installation of PostgreSQL this may not be the case for security reasons, except if both servers are in fact the same machine. In any case, it is recommended that you check the /etc/postgresql/pg_hba.conf file and modify it if needed. This file is self documented and its modification is straightforward. You also have to make sure that PostgreSQL accepts TCP/IP connections. To do so you either have to launch it with the -i option or modify the /etc/postgresql/postgresql.conf file, which is self documented and easy to modify too. Allowing TCP/IP connections is not necessary though if your Quota Storage Server and your Print Server are the very same host. Here's an excerpt from a pg_hba.conf file. This one rejects all connections to PyKota's database excepted when made from the same host by PostgreSQL users pykotauser or pykotaadmin with the correct password. local all postgres ident sameuser local all all reject host pykota pykotauser 127.0.0.1 255.255.255.255 crypt host pykota pykotaadmin 127.0.0.1 255.255.255.255 crypt host pykota all 127.0.0.1 255.255.255.255 reject Of course if your print server and your database servers have different IP addresses, you have to replace the 127.0.0.1 address above with your print server's IP address. As an alternative, you could still keep these lines and add similar lines with other IP addresses if you have several print servers for which you want a single centralized database. Don't forget to restart PostgreSQL if you modify any of its configuration files, in order for the changes to take effect. Be careful, you may be unable to connect from a Print Server to the PostgreSQL server even if the configuration is correct. Sometimes your connections may be blocked by one or more network firewalls along the route from one machine to the other. If this is the case, then the best thing you can do is to ask your Network Administrator to not filter the IP port used by PostgreSQL, which is usually port 5432/tcp. The TCP/IP network port used by PostgreSQL may be different. When in doubt, ask your System Administrator for the correct value. Now that your PostgreSQL server is up and running, and is waiting for your connections, you have to create the Quota Storage DataBase. To do so, you'll have to feed PostgreSQL with the pykota-1.23/initscripts/postgresql/pykota-postgresql.sql file. This file will create a Quota DataBase administrator in the PostgreSQL system, then create an empty Quota DataBase and set some permissions on it. The Quota DataBase administrator is the PostgreSQL's user used to manage the Quota database. The Quota DataBase Administrator is not present in the Quota Database itself, he is only defined in PostgreSQL and don't have to exist on any system, nor in the Quota DataBase. His default name is pykotaadmin. A Quota Storage read-only user is also created under the name of pykotauser. This read-only user is used by PyKota to connect to the Quota Storage when an user who is not a PyKota administrator a PyKota administrator is an user who can read the ~pykota/pykotadmin.conf file. launches a pykota command. This prevents normal users from being able to modify their own, or other users', quota information. The database which will be created will be named pykota by default. You can choose other names if you want, just modify the initscripts/postgresql/pykota-postgresql.sql file accordingly, and report your changes into PyKota's configuration files. To run this script, you can use the psql frontend to PostgreSQL, but your priviledges must be sufficient to be allowed to create users and databases. You can launch psql as the postgres user which is PostgreSQL's default administrator, and connect to the default database named template1. From a command line interpreter (i.e. shell), type the following commands : jerome@nordine:~$ cd pykota-1.23_official/initscripts/postgresql jerome@nordine:~/pykota-1.23_official/initscripts$ psql -h localhost -U postgres template1 Welcome to psql, the PostgreSQL interactive terminal. Type: \copyright for distribution terms \h for help with SQL commands \? for help on internal slash commands \g or terminate with semicolon to execute query \q to quit template1=# \i pykota-postgresql.sql ... a lot of output lines pykota=# If you use RPM or DEB packages, usually the pykota-postgresql.sql file gets installed into the /usr/share/pykota/postgresql directory, along with a README file. For security reasons, you may want to set passwords in PostgreSQL for the pykotaadmin and pykotauser users. Otherwise any user able to connect to PostgreSQL on your Quota Storage Server could connect to the quota database, and either see it, or even modify it without problem. To do so, just type the following lines while still being at the psql prompt (replace the password values by your own, and do the same for the pykotauser user) : pykota=# ALTER USER pykotaadmin PASSWORD 'somepassword'; ALTER USER pykota=# \q jerome@nordine:~/pykota-1.23_official/initscripts/postgresql$ The \q command above will quit the psql program and return you to the shell's command line prompt. To improve security further, you could encrypt your database connections, or take any other step as needed. Please refer to PostgreSQL's documentation for details. Defining passwords may not be sufficient if your database access rule is set to trust in the /etc/postgresql/pg_hba.conf. Again, please refer to PostgreSQL's documentation for details. Also, passwords will fly unencrypted over the network by default, so be sure to take any necessary step to secure your database server from unauthorized use. This has nothing to do with PyKota though, it is just a general rule to keep in mind. If no error occured, then your Quota DataBase is ready to be used. Now you can let the Quota Storage Server alone, the remaining work will have to be done on each one of the print servers which will use this particular Quota Storage Server. If an error occured, maybe your PostgreSQL version is too old, or an unexpected problem (like a bug) happened. Please contact us via email so that we can try to fix the problem. Thanks in advance. Any LDAP server, and particularly OpenLDAP, can be used as a Quota Storage Backend. Some other LDAP servers can be used, but this is currently untested in production. OpenLDAP is a Lightweight Directory Access Protocol server implementation published as Free Software. You can download it from http://www.openldap.org. To use OpenLDAP as your Quota Storage Backend, you have to copy the pykota/initscripts/ldap/pykota.schema into OpenLDAP's schemas directory. Under Debian GNU/Linux, this is something like : $ cp pykota.schema /etc/ldap/schema If you use RPM or DEB packages, the pykota.schema file is usually installed into the /usr/share/pykota/ldap directory, along with a README file, and may also be installed automatically in your LDAP server's schemas directory. Then edit /etc/ldap/slapd.conf and add a line to include the PyKota schema. You should have something like : # Schema and objectClass definitions include /etc/ldap/schema/core.schema include /etc/ldap/schema/cosine.schema include /etc/ldap/schema/nis.schema include /etc/ldap/schema/inetorgperson.schema include /etc/ldap/schema/pykota.schema While this is not mandatory, it is recommended that you setup some indexes for some often accessed PyKota attributes. Here are the minimal indexes lines you may want to put in slapd.conf : # Indexes for PyKota index pykotaUserName pres,eq,sub index pykotaGroupName pres,eq,sub index pykotaPrinterName pres,eq,sub index pykotaBillingCode pres,eq,sub index pykotaLastJobIdent eq Now you must ensure that the DNs you'll use to bind to your OpenLDAP server don't have search queries size limits, which gives for example (OpenLDAP 2.1.x or above) : # No Limits for PyKota's administrator and read-only user limits dn="cn=pykotaadmin,dc=example,dc=com" size.soft=-1 size.hard=soft limits dn="cn=pykotauser,dc=example,dc=com" size.soft=-1 size.hard=soft Where pykotaadmin and pykotauser are the usernames used to bind to your OpenLDAP server within PyKota, respectively in ReadWrite mode (as set in pykotadmin.conf) and in ReadOnly mode (as set in pykota.conf). Finally, stop the OpenLDAP server, generate the index files, and restart OpenLDAP $ /etc/init.d/slapd stop $ slapindex $ /etc/init.d/slapd start With an LDAP backend, PyKota will need some branches in your LDAP directory to put its own datas. You can configure PyKota to either attach its datas to your existing users and groups, or to put them in their own ou. But some ous dedicated to PyKota are needed in any case, so the best bet may be to put all PyKota's datas below an ou=PyKota branch. While this will separate these datas from your existing users and groups entries, this may ease the maintainance. PyKota needs at least an ou for printers, for users quotas, for groups quotas, for print jobs, for billing codes, and for pointers to the last job of each printer. In the future, this last ou may disappear as its content will probably be attached to each printer. Actually PyKota doesn't create these ous for you, because it's difficult to guess what is the best configuration for you. So you have to create them by yourself, either directly with a text editor and the ldapadd command, or with some specialized tool like gq. You can look at the initscripts/ldap/pykota-sample.ldif file to see which minimal branches are necessary. If you use RPM or DEB packages, usually the pykota-sample.ldif file is installed into the /usr/share/pykota/ldap directory, along with a README file. If no error occured, then your Quota DataBase is ready to be used. Now you can let the Quota Storage Server alone, the remaining work will have to be done on each one of the print servers which will use this particular Quota Storage Server. If an error occured, maybe your OpenLDAP version is too old, or an unexpected problem (like a bug) happened. Please contact us via email so that we can try to fix the problem. Thanks in advance. A MySQL Storage Backend is planned, but it actually doesn't exist. A Berkeley DB Storage Backend is planned, but it actually doesn't exist. It seems that remote storage won't be possible with such a backend, so in other terms this means that you will have a different quota database on each print server. This may still prove to be useful for small configurations. For each Print Server on which you plan to implement the print quota mechanism, you have, of course, to have an already working printing environment. Currently PyKota works with CUPS but older releases also supported LPRng. LPRng support might be re-added in the future. Here's the list of software you have to install on each Print Server, version numbers are given as an indication of which was successfully tested, but older versions may work too. CUPS version 1.1.14 or above. You can download it from http://www.cups.org Python version 2.1 or above. You can download it from http://www.python.org. While PyKota itself will try to preserve compatibility with Python version 2.1 for the near future, some Python modules which are needed by PyKota may mandate the use of a more recent version of this language. Quota Storage client libraries, depending on your Quota Storage Backend : PostgreSQL backend : PostgreSQL client libraries. They must match the PostgreSQL version used on your Quota Storage Server. The PygreSQL python module. It must have been compiled against the same PostgreSQL client libraries. PygreSQL is normally included in PostgreSQL, but you may want to download it from http://www.pygresql.org OpenLDAP backend : OpenLDAP client libraries. They must match the OpenLDAP version used on your Quota Storage Server. The Python-LDAP python module. It must have been compiled against the same OpenLDAP client libraries. You may download this module from http://python-ldap.sourceforge.net MySQL backend : Not supported yet. Berkeley DB backend : Not supported yet. ucd-snmp or net-snmp tools, version 4.2.5 or above. You only need the snmpget command. You can download this software from http://www.sourceforge.net/projects/net-snmp/. You only need this if you plan to query your printers for their internal page counter via SNMP. netatalk version 1.6.1 or above. You only need the pap command. You can download this software from http://netatalk.sourceforge.net/. You only need this if you plan to query your printers for their internal page counter via AppleTalk. eGenix' mxDateTime Python module version 2.0.3 or above. It must match your default Python version. You can download it from http://www.egenix.com. The Python acccelerator Psyco. It must match your default Python version. You can download it from http://psyco.sourceforge.net. You only need this if you run on the x86 architecture because Psyco doesn't yet exist on other architectures. The pysnmp Python module version 3.4.2, 3.4.3 or 3.4.4 exclusively. You can download it from http://pysnmp.sourceforge.net. The JAXML Python module. You can download it from http://www.librelogiciel.com/software/. The ReportLab Toolkit Python module. You can download it from http://www.reportlab.org. The Python Imaging Library - PIL module. You can download it from http://www.pythonware.com. The PyOSD Python module. You can download it from http://repose.cx/pyosd/. The pkpgcounter Generic Page Description Language parser. You can download it from http://www.librelogiciel.com/software/. Instead of downloading all these programs' sources and compiling them, which really is a boring task considering that many software are needed, you may prefer to look into the packages included with your GNU/Linux distribution of choice (if you use this operating system of course). Most, if not all, GNU/Linux distributions include all the software mentionned above, in the form of packages which are easier to install than sources tarballs. This is probably the same for the many *BSD distributions. You can check that all needed software is installed by launching the checkdeps.py command : $ python checkdeps.py Once all these software are installed, installing PyKota itself is a breeze. PyKota being written entirely in the Python language, which is interpreted, there's no need to compile anything. You just have to execute the installation script : $ python setup.py install The setup script will automatically create the /usr/share/pykota/conf directory and put the sample configuration files conf/pykota.conf.sample and conf/pykotadmin.conf.sample there, along with a README file explaining their purpose. Now you have to create a pykota system user and group. The PyKota software will automatically search its configuration files in user pykota's home directory. For example we could create the user and group, and set /etc/pykota as the home directory, but any other home directory will do : adduser --system --group --home /etc/pykota --gecos PyKota pykota You now have to copy the sample configuration files into the ~pykota directory, under the respective names pykota.conf and pykotadmin.conf. Once copied there, you just have to modify these files to adapt them to your own setup. These files are heavily commented, so you should have no problem. Also their format is quite common, because it's the one used by Samba for example, or by .ini files under MS-Windows, so you may already be familiar with this syntax. In a future release, this documentation will include the complete reference for all configuration fields available. Keep in mind that PyKota can be really heavily customized, and can delegate some work to any external command of your choice. Please create a backup copy of the ~pykota directory before modifying a working installation. PyKota features some interesting possibilities which allow you to define options either globally so that they apply to all printers, or on a per printer basis. Please see the sample configuration files to see what I mean. In the simplest form, only a [global] section is needed. In more complex configurations, you will have to create one section per printer. Each section in the configuration files begins with a name between square brackets []. The name to use to define a particular printer section is the name of the print queue on which you want to set quotas. After you have modified PyKota's configuration files, you have to double check their permissions, otherwise your installation may be insecure or may not work at all. The main configuration file ~pykota/pykota.conf doesn't contain much sensitive information, so it can be made readable by anyone. If normal users read this file, at best they will learn the username and optional password of the read-only database user. This means that beside being allowed to read all the contents of the quota database, they won't be allowed to modify or delete it. On the other hand, the ~pykota/pykotadmin.conf file contains the read-write user's identity and password. You must then ensure that no normal user can read this file. It should only be readable by the root user, which is always the case, and by PyKota administrators. In addition, users for which CUPS doesn't run as user root will have to ensure that the user their printing system is run as can read both of these files. An easy way to do so is to put the lp user (for example) into the pykota system group, then to give the correct permissions to PyKota's configuration files : $ chown pykota.pykota ~pykota/pykota.conf $ chmod 644 ~pykota/pykota.conf $ chown pykota.pykota ~pykota/pykotadmin.conf $ chmod 640 ~pykota/pykotadmin.conf All the users allowed to read the ~pykota/pykotadmin.conf are considered to be PyKota administrators. So be careful with these files permissions. On some systems, you may be able to strenghten permissions like this : $ chown pykota.pykota ~pykota/pykota.conf $ chmod 640 ~pykota/pykota.conf $ chown pykota.pykota ~pykota/pykotadmin.conf $ chmod 600 ~pykota/pykotadmin.conf And on other ones, you may need to relax them, and change the files' owner : $ chown lp.pykota ~pykota/pykota.conf $ chmod 640 ~pykota/pykota.conf $ chown lp.pykota ~pykota/pykotadmin.conf $ chmod 640 ~pykota/pykotadmin.conf This all depends on the printing system you are using, and the user the printing system is usually running as. You need to remember two things : The user your printing system runs as MUST be allowed to read both PyKota's configuration files. Any user who can read pykotadmin.conf is a PyKota administrator, and can do whatever he wants to the print quota database. Don't forget to restart your print server sofware if you changed group membership for the user it runs as, otherwise your change wouldn't be taken into account. Now depending on your printing system, the configuration to do is particular. We will now see how to plug PyKota into your printing system. From version 1.16alpha7 on, configuring PyKota to integrate within CUPS is more than easy. You just have to create a symbolic link to the cupspykota command in CUPS' backend directory : $ cd /usr/lib/cups/backend $ ln -s /usr/share/pykota/cupspykota cupspykota You have to restart CUPS for this modification to take effect : $ /etc/init.d/cupsys restart Now point your web browser to CUPS configuration page, usually at http://localhost:631 on your print server. Then when creating new printers or reconfiguring existing ones, just choose devices which are PyKota managed Debian 3.0 Woody is known to have problems : CUPS 1.1.14 doesn't automatically detect PyKota managed devices. So you have to manually modify CUPS' printers.conf file as explained in PyKota's toplevel README file. instead of normal devices. You've got one PyKota managed device for each regular device available from CUPS, so just choose the appropriate one. Repeat the above procedure for each print queue on which you want to use PyKota. That's all ! In case of problem, the simplest way to solve it is currently to ask on PyKota's mailing list, describing the symptoms, as well as the hardware and software you use. In a future release of this document, a section dedicated to Frequently Asked Questions will be included. You can now also ask us questions on IRC : /server irc.freenode.net /join #pykota