Problems with CUPS

Some of the problems which appear to be CUPS related are actually caused by things like applications producing faulty postscript, here are some hints to keep things going.

Note that MDP and chargeable (AT) print queues go via the IS printing system. You can access their print logs etc via https://www.manageprint.is.ed.ac.uk/

Hints

Login to infcups and run a browser there - connect to http://localhost:631/ (you may need to kill off existing browser windows first) Open a window on infcups and become root.

If a printer has jobs queued but says something like, 'Waiting for job to complete' or 'Printer busy - retrying in X seconds' and nothing is moving. Make sure that the web interface doesn't show 2 jobs for the same printer listed as 'processing'. On infcups do 'ps -fe' and grep for the printer's DNS name (note name e.g. philadelphia not alias if513m1). There should only be one ipp process per printer. You can usually kill off any obviously day or more old processes.

Check the number of the job that's stuck at the head of the queue and do lp -i jobNumber -H hold

this should stop the job at the top of the queue and let the second and subsequent jobs go.

If you have two ipp's processing you may need to hold everything, until you get down to just one ipp. You can then resume the jobs (as above replacing hold with resume ) If you leave it until last you can sometimes even resume the original stuck job, and it'll work. Alternatively just lprm it.

On Canon MFDs you may need to power-cycle the machine if it's chewing bad postscript. It's web interface may show - deleting/canceling. Trying to soft power-cycle just leaves the same hanging state.

-- GordonReid - 30 Jun 2009

If cloud printing is down

There are basically three parts to cloud printing:

  1. the spooling of jobs to the cloud from the client
  2. authentication at the cloud printer to enable copying/scanning/releasing of print jobs
  3. spooling print jobs from the cloud to the printer

We are more or less at the mercy of IS to solve any problems with the above, however a recent problem with step two, the authentication, meant we discovered a work around that would at least enable copying and scanning again for an affected cloud printer.

2 Allowing anonymous scanning/copying on a cloud printer

The following should only be temporary fix while IS are having problems, it should be reverted once the problem has been resolved.

  1. Log in to the web interface of the device you want to enable unauthenticated copying and scanning. Details of which can be found in /afs/inf.ed.ac.uk/group/services-unit/printing/xerox/useful

  2. In Properties -> Login/Permissions/Accounting set:
    • xerox-acc.png Accounting Methods to "None" (from "Network")

    • xerox-anon.png User Permissions -> User Permissions Roles -> Non-Logged-In Users -> Services & Tools to "Allow access to everything except Tools (Standard Access)", the previous setting was "Custom" where everything was denied apart from Jobs Status and Job deletion, which was allowed.

-- CraigStrachan - 05 Apr 2007

Topic revision: r5 - 12 Jun 2018 - 09:51:21 - NeilBrown
 
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