It requires you to install CrashPlan on your client computer, manually editing a config file, and using SSH port forwarding.
==Troubleshooting==
===Fixing Java RTE errors on the CrashPlan desktop===
If you use the CrashPlan desktop on version 3.5.3 you may experience a Java error - when starting the Crashplan desktop the splash image shows for a few seconds, and then vanishes, but the application doesn't open.
It appears that CrashPlan 3.5.3 bundles a buggy version of the "Eclipse Standard Widget Toolkit". To fix, you just need to replace that toolkit with the latest one from the developer.
Download swt-4.3-gtk-linux-x86.zip and swt-4.3-gtk-linux-x86_64.zip from [http://download.eclipse.org/eclipse/downloads/drops4/R-4.3-201306052000/#SWT Eclipse].
Extract swt.jar from the x86_64 file and rename it as swt-64.jar, and extract swt.jar from the second file. I saved them both to the home directory. (You can do this from terminal from the directory in which you saved the .zip files):
{{Code|unzip -e swt-4.3-gtk-linux-x86_64.zip swt.jar -d ~
mv ~/swt.jar ~/swt-64.jar
unzip -e swt-4.3-gtk-linux-x86.zip swt.jar -d ~}}
Then you need to copy these to the CrashPlan library. On my HDA CrashPlan was installed to /var/hda/web-apps/crashplan/html. If your installation is different you will need to replace the commands below this your directory.
Stop the crashplan server
{{Code|sudo systemctl stop crashplan.service}}
Back up the old files and copy in the new ones
{{Code|cd /var/hda/web-apps/crashplan/html/lib **change this to your own installation if it is different, remember to put the /lib at the end**
mv swt.jar swt.jar.old
mv swt-64.jar swt-64.jar.old
mv ~/swt.jar swt.jar
mv ~/swt-64.jar swt-64.jar}}
Restart the crashplan server
Stop the crashplan server
{{Code|sudo systemctl start crashplan.service}}
Should be working now.
[Source: [https://forums.amahi.org/viewtopic.php?f=26&t=4951 this forum post]]