Selfhosted @lemmy.world avnrt @lemmy.world 1y ago

[Help] Backing up Nextcloud with Duplicati (Docker)

I would like to back up my nextcloud data using duplicati, but I absolutely can‘t figure out how to give Duplicati access to the Nextcloud volume. Both are running fine in separate Docker containers. I can’t figure out how to properly mount the volume, below is my current compose for duplicati. Do I need to mount the volume as source? Does it need to be declared or mapped separately?

---
version: "2.1"
services:
  duplicati:
    image: lscr.io/linuxserver/duplicati:latest
    container_name: duplicati
    environment:
      - PUID=1000
      - PGID=1000
      - TZ=XXX
      - CLI_ARGS= #optional
    volumes:
      - /path/to/appdata/config:/config
      - /path/to/backups:/backups
      - /path/to/source:/var/lib/docker/volumes/073ac2751cd65ffd84750e578c38482905c3c7e4851a8cbb0bbbc5c33a285e84
    ports:
      - 8200:8200
    restart: unless-stopped

16 comments

You might try adding :rw after each of your volume paths, like this:

volumes: - /path/to/appdata/config:/config:rw

My honest suggestion would be to ditch Duplicati for Duplicacy. Duplicacy is one time payment, but it's much more polished than Duplicati. I actually had major issues with recovering files from Duplicati; sometimes it would work and sometimes it wouldn't. Not ideal for something as critical as backup software.
- But it should not need write access to those files.
  
  I bet it is due to different UID. Nextcloud runs with the www-data user, and UID 1000 is likely whatever user OP set up on the host machine. Make Duplicati run with the same UID as nextcloud and it will have the permission to read the files.
  
  You are probably correct! I always forget about the UID..
  
  IIRC nextcloud docker image uses UID 33 instead of 1000.
- I'll take a look at Duplicacy, thanks
You've got your path backwards, do:

/var/lib/docker/volumes:/source

And then access the data at /source in Duplicati.
- Thanks! A drop down chevron has appeared next to the "Source Data" folder in duplicati, but it is still empty, showing neither the volume, nor its contents. Any idea what else I can try/modify?
  
  Does it show the root / filesystem inside the container?
  
  You may need to update the folder permissions on the Nextcloud volume to allow all users to read data.
Why are you mounting the volume with the file system path, instead of the volume name? You should be able to mount the volume normally by specifying it in the volume section, i.e.

services: duplicati: volumes: - nextcloud_data:ro volumes: - nextcloud_data - external: true

That should grant Duplicati read-only access to the entire volume without messing around with absolute file paths.
- Thanks, I didn't fully understand the syntax before. I now see the volume in the duplicati GUI, but not its contents. When I just back up the entire volume, the backup size is basically zero (should be more like 800MB).

16 comments