Arangodump backup to a USB drive from within a docker container?

Question

I'm running ArangoDB version 3.8.0 in a docker container on my primary drive on Ubuntu 21.04.

That drive is unfortunately full, and I can't clear enough data to make a backup.

I have the folder /dumps in the container mapped to a place on that drive, /media/m/Data/.

I do however have a USB drive with enough space to store the backup, but I can't figure out how to get Arango to dump to a harddrive connected via USB. I believe the answer will involve mapping the drive to somewhere in the docker container, but I don't know enough about how docker works to solve this on my own.

Things tried:

Set arangodumps output directory to /dev/fd/1 -> FATAL {dump} cannot write to output directory /dev/fd/1

Changed the mapping of the drive in /usr/lib/systemd/system/docker.service -> container disappeared, thought I lost the data and panicked a little. Changed it back and everything was okay.

Answer 1

You cannot add a mount to your running container. However you can do as described here: How can I add a volume to an existing Docker container?

• Commit your container
• Run the new image with added mount
• Check if the container has all your changes make you dump in this container

Answer 2

Managed to solve this problem by installing arango on another machine on the same network with the USB drive and ran:

arangodump --output-directory <Mounted USB drive> --server.endpoint <local IP:8529 of the over-full computer> 

And it dumped to the USB drive!