After some very expensive shenangians with my old Raspberry Pi 3B+ and a screwdriver (more to come) I found myself in need of a new device for my print server
This is easy to achieve I feel that I had to go through many guides and troubleshooting posts before making it work as expected so I’m making yet another guide in hopes to cover all aspects of it for your home server
Odroid SoCs
Odroid series are a Raspberry competitor line of SoCs made by Hardkernel, a South Korea company which offers a very wide variety of SoCs and more consumer-oriented devices based on several chips (Exynos, Rockchip, Amlogic). One of their popular boards is the Odroid-XU4, which, while lacking in some features to the Raspberry 4 it offers similar specs at a more reasonable price (scalpers considered). A plus on this model is that it comes with an extension port for an eMMC storage, which outperforms microSD by a large margin on I/O. Oh, and it has a power button
Printing over the network
Having to print over the USB wire is only valid if the host is connected to the printer and said printer is on the side of said host. Having the printer far away, or introducing multiple devices as print sources complicates this a bit
Instead of sending files over emails, pendrives or having to do strange movements with your USB cables, having a single point is more useful, and even needed. A print server is essentially that: you have your printer visible over the network from any device connected in the same network
CUPS
CUPS (Common UNIX Printing System) is an open source print server developed and maintained by Apple, designed to enable administration of printers and jobs over a network. It is also very lightweight and can be used on minimal distribution without many dependencies
Armbian
Armbian is an open linux ARM distro targeting a lot of development boards, and up to date (current releases are based on Ubuntu Jammy)
While Odroid provides official builds for the XU4, these are based on Ubuntu Focal and Armbian’s are more updated. It also provides more useful a barebones distro optimized for the board and other future purposes (since this board is extremely overkill for a print server, I know)
CUPS setup on Armbian
Aside from being an armhf distro, Armbian is pretty mature and the setup is as straightforward as it is on other platforms (and it also has a configuration wizard for the first boot, allowing the user to choose between bash and zsh). The gist here is getting around printer drivers and configuration
Dependencies
The first step is to install CUPS, its PDF backend, the GIMP driver backends and the printer backend for Canon BJNP protocol (pretty important if, well, you’re using a Canon printer). Second step is to create an user (call it cupsadmin) and add it to the lpadmin group, which is the one authorized by the CUPS service for most operations. Also, samba to enable network access to the PDF printer destination
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Base configuration
Following step is to configure everything. With this basic configuration, we’re telling CUPS to enable LAN access to its web interface on port 631 (its default) requiring the credentials of any user belonging to the lpadmin grpup (namely, cupsadmin, but can be whichever you want).
Using the example base configuration, make the following changes to /etc/cups/cupsd.conf:
Browsing On
# Disable cups internal logging - use logrotate instead
MaxLogSize 0
# Log general information in error_log - change "warn" to "debug"
# for troubleshooting...
LogLevel warn
#PageLogFormat
Listen /run/cups/cups.sock
Listen 0.0.0.0:631
Port 631
# Show shared printers on the local network.
Browsing On
BrowseLocalProtocols dnssd
LogLevel warn
MaxLogSize 1m
Listen 0.0.0.0:631
Listen /run/cups/cups.sock
Port 631
Browsing On
BrowseLocalProtocols dnssd
DefaultAuthType Basic
WebInterface Yes
<Location />
Order allow,deny
Allow localhost
Allow from 192.168.*.*
Allow from 10.0.*.*
</Location>
<Location /admin>
AuthType Basic
Require group lpadmin
Allow all
Order allow,deny
</Location>
<Location /admin/conf>
AuthType Basic
Require group lpadmin
Allow all
Order allow,deny
</Location>
<Location /admin/log>
AuthType Basic
Require group lpadmin
Allow all
Order allow,deny
</Location>
MaxJobs 0
PreserveJobFiles No
PreserveJobHistory No
Adding printers
Paraphrasing Robert van den Aker
- Access the CUPS web interface through the printers panel in the server-manager. Accessing it this way rather than directly has the advantage that you’ll already be logged into the server-manager for “synchronizing the printer lists”, which you need to do after adding or deleting printers through the CUPS web interface. Log on to the CUPS web interface as “admin”.
- In the CUPS web interface, choose “Do Administration Tasks”, then choose “Add a New Printer”. The local devices visible by CUPS will be available to add as a service printer. I have a Canon G3100 so I have these options:
- CUPS-BRF (Virtual Braille BRF Printer)
- Canon G3000 series (Canon G3000 series)
- CUPS-PDF (Virtual PDF Printer)
- Pick a name for your printer. “Location” and “Description” are optional. Please note that the “Location” entry is meant for descriptive information about the physical location of your printer, like “Printer room” or “Cupboard upstairs” or even “Honolulu” if you do remote printing. In the case of a PDF printer there is no physical printer location and you can leave this empty.
- Select the
Share this printercheckbox, this is very important for it be network-accessible - Press
Continue. - Select a driver. As the one I need is provided by gutenprint, in my case it is
Canon PIXMA G3000 - CUPS+Gutenprint v5.3.3. CUPS provides generic and raw drivers if needed - Press
Add Printer
To add the PDF printer as a network device, steps are the same (minus the driver selection).
Default settings
If having multiple printers like the physical and virtual PDF devices it’s a good idea to set the physical as the server default (Select your printer in the Printers section and then select the Set As Server Default action on the Maintenance dropbox)
While it’s the host OS the one that defines the print’s settings it’s also a good idea to set the default options on the CUPS printer that match your device’s specs. This is done by the Set Default Options action on the Maintenance dropbox. When getting the printer recognized over the network by a client the options will probably be to set up again the the device on that client, but it’s important to keep consistency
PDFs over the network
To make the PDF printer fully functional there is a final step remaining which is configuring and sharing its output directory. Asuming user cupsadmin:
Set up the samba configuration:
[sambashare]
comment = Samba on Armbian
path = /home/cupsadmin/sambashare/
read only = no
browsable = yes
And create a samba password for the user:
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Now edit the CUPS-pdf config on /etc/cups/cups-pdf.conf and set the output directory to be the samba share:
Out /home/cupsadmin/sambashare/
Finally, restart the cups and samba services
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Troubleshooting
I spent a couple of hours dealing with this (no so unusual) error on the CUPS server which made jobs fail silently:
HTTP_STATE_WAITING Closing for error 32 (Broken pipe)
There are lots of links when searching but it usually boils down to one of these:
- Network connectivity issue (firewall rules and whatnot)
- CUPS driver issue (this was my issue, I needed the BJNP backend for my Canon printer)
After sorting that out, I couldn’t print in color. That required setting up appropiate defauls on the server printer and resetting the CUPS service
Bonus track
On Armbian (and any linux distro in general), you can manually execute the motd scripts. The one that shows the sensor readings and system stats is this one:
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(replace zsh if you didn’t pick it up as the default shell)
