Configuring the printer on a Linux NICE DCV Server - NICE DCV
Troubleshooting printer issues
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Configuring the printer on a Linux NICE DCV Server

NICE DCV allows you to print either to a local redirected printer or to a virtual NICE DCV printer.

If you're using a supported Linux distribution, you must configure the NICE DCV server to support printing.

If you're using a Windows NICE DCV server, no additional configuration is required.

To enable printer redirection on your Linux NICE DCV server

  1. Install CUPS service on your server.

    • Amazon Linux 2, RHEL, and CentOS

      $ sudo yum install cups

    • Ubuntu

      $ sudo apt-get install cups

    • SUSE Linux Enterprise

      $ sudo zypper install cups

  2. Add the dcv user to the printer administrator group. The name of the printer administrator group can vary by operating system. For example, if your printer administrator group is named lpadmin, run the following command:

    $ usermod -a -G lpadmin dcv

  3. Make sure that the printer administrator group is referenced in the SystemGroup parameter in the cups configuration file. For example, if your printer administrator group is named lpadmin, use a text editor to open /etc/cups/cups-files.conf and look for the following line.

    SystemGroup lpadmin

    If the line appears in the configuration file, the installation is complete. Continue to the next step.

    If the line doesn't appear in the configuration file, add it manually in the following format and then save and close the file.

    SystemGroup printer_admin_groupname

  4. (SUSE Linux Enterprise only) Make sure that the printer administrator group has permission to read the cups local certificate. This certificate is located in the following directory: /var/run/cups/certs/. For example, if your printer administrator group is named lpadmin, run the following command:

    $ sudo chgrp -R lpadmin /var/run/cups/certs/ && chmod g+x /var/run/cups/certs

  5. Restart the cups service.

    $ sudo systemctl restart cups

  6. Stop and restart the NICE DCV server.

Troubleshooting printer issues

SUSE Linux Enterprise and RHEL 8 might prevent connections to the printer socket. If you're running one of these operating systems and have printing issues, check the log file to determine if this is the cause.

Using a text editor, open /var/log/audit/audit.log and check if you log has a line that's similar to the following:

type=AVC msg=audit(1617716179.487:504): avc:  denied  { connectto } for  pid=33933 comm="dcvcupsbackend" path=002F636F6D2F6E696365736F6674776172652F6463762F637570732F636F6E736F6C65 scontext=system_u:system_r:cupsd_t:s0-s0:c0.c1023 tcontext=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 tclass=unix_stream_socket permissive=0

If a similar line appears in your log file, then the operating system is preventing access to the printer socket.

To resolve the issue, you must create a cups policy that allows access to the printer socket. To do this, perform the following steps:

  1. Create the required policy file. Using your preferred text editor, create a new file that's named cupsd_policy and add the following content.

    #============= cupsd_t ==============
allow cupsd_t unconfined_t:unix_stream_socket connectto;

  2. Install the policy.

    $ ausearch -c 'dcvcupsbackend' --raw | audit2allow -M dcv-printer-policy
    $ semodule -X 300 -i dcv-printer-policy.pp