Hi,
as those of you also subscribed to the x2go-user mailing list might already have noticed, I'm currently evaluating X2Go-ThinClient-Edition. This is purely for my own, at-home use, as opposed to the published application mode, which I'm using commercially.
One thing that has always annoyed me about X2Go is the mechanism for printing to a locally-attached client printer.
Especially in a thinclient, LAN-only setup, it seems like an unnecessary complex solution to a trivial problem.
My solution: Make the ThinClients behave like a "HP JetDirect" card.
This can easily be done like this (on the server supplying the TC NFS root):
chroot /opt/x2gothinclient/chroot apt-get install openbsd-inetd -y echo "9100 stream tcp nowait root /bin/dd if=- of=/dev/usb/lp0 bs=1024k"
/etc/inetd.conf echo "9101 stream tcp nowait root /bin/dd if=- of=/dev/usb/lp1 bs=1024k" /etc/inetd.conf
Assumption: Thinclients will have no more than two locally attached printers. For more, simply keep adding lines and increment the port numbers by 1 (9102: /dev/usb/lpt2, 9103: /dev/usb/lpt3, etc).
For more flexibility, this could also be created dynamically at boot, by turning inetd.conf into a symlink to a writable file on a ramdisk, and a script checking for the presence of /dev/usb/lp* and /dev/lp* (in case somebody uses an ancient computer with a parallel printer as thinclient).
With this addition (either statically as shown above, or with the use of a script), all you need to do on the CUPS server is set up a printer and specify socket://name-or-ip-of-the-thinclient:portnumber, e.g. socket://thinclient01.example.com:9100, as AppSocket/HP JetDirect URI in CUPS.
Now, this will end up in a mess if you're assigning IPs dynamically via DHCP, and you aren't matching them up with the thinclients' MAC addresses.
The easy solution for that would be using a DNS name, however, right now, it looks like all X2Go thin clients don't request/suggest a DNS name via DHCP, and use the same name "x2gothinclient" locally. Seems like "send host-name = gethostname();" in /etc/dhcp/dhclient.conf somehow doesn't work properly in the thin client environment - possibly because PXE already pulls a DHCP IP and doesn't know about the name? I'm not sure what the mechanism there does.
Therefore, I would like to suggest the addition of some code that adds an individual name to each client, and requests/suggests that via DHCP. The MAC address would come in handy for that. A method to query the MAC address of the currently active interface would be:
IFACE=$(route -n | awk '/^0.0.0.0/ { print $8 }' | head -1) MAC=$( ip a l $IFACE | awk '/^ *link/ { print $2 }' | tr ':' '-' ) hostname "$(cat /etc/hostname)-$MAC" # this sets the hostname dhclient -sf /dev/null $IFACE # this re-registers our lease and updates the name on the DHCP/DNS server, without complaining about a read-only resolv.conf-file # NB: Yes, you really need to use /dev/null, not /dev/zero.
Notes:
- This is a quick hack, feel free to improve it
- I'm not sure where this should be inserted, only that it should be inserted. ;-) Right now, I'm running it in rc.local, but there must be a better place for this. The earlier in the boot process, the better. Maybe as a script in /etc/network/if-up.d/ ?
- I don't know if changing the host name without changing /etc/hostname and /etc/hosts might have some undesired side effects. If it does, these files might have to be symlinked to a ramdisk.
-Stefan