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Department of Computer Science Printing System Administration (CUPS)

This document describes how to maintain the CUPS printing system in the Department of Computer Science. I will not go into how to set up the system as there are some well written documentation on the web. I will provide links and some helpfull hints.

CUPS printing system in the Department of Computer Science

Installation and configuration

The documentation available at http://www.cups.org/sam.html is well written and comprehensive.

Computer Science Administration

• 3.1 Managing printers
• 3.2 Adding clients
• 3.3 Problem Determination and Logs

There are 2 servers running cups in the department. crystal.cs.yale.edu and cyndra.cs.yale.edu.

TO DO: Keep the print servers configurations in sync...

3.1 Managing printers

Adding a new printer or managing an exisiting one can easily be done through the web interface either http://cyndra.cs.yale.edu:631/admin or http://wkspt6.cs.yale.edu/:631/admin. You know the admin user and password, right?

A majority of the HP LaserJet printers were also configured to use the generic HP LaserJet drivers because we found that the model specific drivers did not implement duplex printing. For higher quality print jobs, it might be beneficial to use the model specific drivers.

When adding a printer, it's important to be specific in the description field. For example, don't just enter "LaserJet 4050N" enter "Fourth Floor - LaserJet 4050N". This is because by default, OS X clients identify printers according to their description, and so, within one building there may be three LaserJet 4050Ns.

WARNING: Any changes made on one server MUST be made on the other. There is currently no automagic way of doing this.

3.2 Adding clients

Linux

The linux clients should be running the cupsd daemon to take advantage of having backup print servers. The post-install-cs-9 script on the ftp server will take care of new machines.

To enable a linux client to print through the servers edit the /etc/cups/cupsd.conf file and add the server IP addresses:

BrowsePoll 128.36.229.87:631
BrowsePoll 128.36.229.125:631
       

and then restart the cupsd daemon...

/etc/rc.d/init.d/cups restart
       

If you don't wish to run the cups daemon you can also print through the servers by editing /etc/cups/client.conf and adding:

ServerName server
       

However, If that server goes down printing service will be disabled.

You should also check to make sure you are using the correct printer binaries. RedHat has a gui to switch between LPRng and CUPS, redhat-switch-printer. You can also use the alternatives command.

/usr/sbin/alternatives --display print
       

will show what printer binaries are currently selected.

/usr/sbin/alternatives --set print /usr/bin/lpr.cups
       

will set the print binaries to the cups version.

Setting default printer and options lpoptions -d printer

MacOS X

Adding a MacOS X client is the same as the linux client.

WARNING: I found that if I didn't use the cups daemon and use the client.conf file I cannot print from the MacOS X GUI. Only from the shell.

NOTE: Mac OS X does not set ImplicitClasses by default http://cyndra:631/sam.html#ImplicitClasses and configuring for two servers will show double the printers available. Edit /etc/cups/cupsd.conf and set

ImplicitClasses On

Windows

NOTE: Windows does not use a cups daemon for spooling and cannot take advantage of redundant print servers. Sorry.

• Printer Wizard

  To add a printer to a Windows machine open the Printer Wizard and run though the network printer install steps.

• Browse method

  Open the windows printer folder on the server with:

  [ Start ]

  [ Run ]

  [ \\cyndra ]

  Right click on the printer icon and select connect.... The printer should now be configured for use.

3.3 Problem determination and logs

lpstat -o : list jobs in queue

/usr/bin/cancel job-id : remove a stuck job from the queue

lpstat -p : list status of printers

Logs can be found in

/var/log/cups
   

http://cyndra:631/sam.html#PRINTER_ACCOUNTING gives a description of log formats.

User Help

• How to use CUPS
• Linux users can check printer status with a web browser

Online Documentation and References

• Cups Documentation http://cyndra.cs.yale.edu:631/documentation.html
• Cups System Admin Documentation http://cyndra.cs.yale.edu:631/sam.html
• Cups User Guide Documentation http://cyndra.cs.yale.edu:631/sum.html