Printers are disappearing after CUPS is restarted in RHEL 7 and later versions

Issue

• We configured some printers on Tuesday. We checked the printers the same day and they were still available, but now the printers are not available on this server and we did not remove the printers.

• Some printers are being removed after CUPS restarts. For example, we create some print queues:

  # lpadmin -p ABS2-12 -E -v socket://10.185.35.224
  # lpadmin -p ABS2-11 -E -v socket://10.185.35.223
  

  and then check to make sure the queues are configured:

  # lpstat -t | grep ABS2-12
  device for ABS2-12: socket://10.185.35.224
  ABS2-12 accepting requests since Mon 26 Sep 2022 08:56:51 AM GMT
  printer ABS2-12 is idle.  enabled since Mon 26 Sep 2022 08:56:51 AM GMT
  # lpstat -t | grep ABS2-11
  device for ABS2-11: socket://10.185.35.223
  ABS2-11 accepting requests since Mon 26 Sep 2022 08:56:55 AM GMT
  printer ABS2-11 is idle.  enabled since Mon 26 Sep 2022 08:56:55 AM GMT
  

  but after we restart CUPS:

  # systemctl restart cups
  # systemctl status cups
  ● cups.service - CUPS Printing Service
     Loaded: loaded (/usr/lib/systemd/system/cups.service; enabled; vendor preset: enabled)
     Active: active (running) since Mon 2022-09-26 08:57:36 GMT; 6s ago
   Main PID: 5999 (cupsd)
     CGroup: /system.slice/cups.service
             └─5999 /usr/sbin/cupsd -f
  

  the queues are gone:

  # lpstat -t | grep ABS2-12
  # lpstat -t | grep ABS2-11