Cannot backup level.dat and playerdata

[utsudashinou]

Describe the problem

I use tarball backup method. And backups are stored file server via NFS.

When I update latest images, suddenly, this message appeared.

backups-1  | tar: ./world/playerdata/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.dat: Cannot open: Permission denied
backups-1  | tar: ./world/level.dat: Cannot open: Permission denied
backups-1  | tar: ./world/level.dat_old: Cannot open: Permission denied

Permission of files of playerdata directory and level.dat are 600. I tried to chmod 622, but permission was overwritten, when started container and logined minecraft.

Container definition

services:
  mc:
    image: itzg/minecraft-server
    tty: true
    stdin_open: true
    restart: unless-stopped
    ports:
      - 25565:25565
    environment:
      EULA: "TRUE"
      VERSION: "1.21.6"
      ICON: /icon.png
      OVERRIDE_ICON: true
      #WORLD: /base
      MEMORY: 3G
      OPS: "UtsudaShinou"
      MAX_PLAYERS: 2
      MAX_TICK_TIME: "-1"
    volumes:
      - mc:/data
      - ./server-icon.png:/icon.png
      #- ./world:/base
  backups:
    image: itzg/mc-backup
    environment:
      BACKUP_INTERVAL: "24h"
      PRUNE_BACKUPS_DAYS: 3
      # instead of network_mode below, could declare RCON_HOST
      # RCON_HOST: mc
    volumes:
      # mount the same volume used by server, but read-only
      - mc:/data:ro
      # use a host attached directory so that it in turn can be backed up
      # to external/cloud storage
      - ./mc-backups:/backups
    # share network namespace with server to simplify rcon access
    network_mode: "service:mc"

volumes:
  mc:

Container logs

Edit: Moved to here

[itzg]

I'm not sure so far what it might be doing.

Can you provide more of the backup container logs surrounding that error?

Thanks for checking the permission bits. Can you also check the owner of the world files it doesn't like? Use ls -ld to see if the numerical user ID owner matches up.

[MacKey-255]

@utsudashinou try to use:

chown 1000:1000 ../minecraft/ -R

Tips:

• Add :z to volumes to indicating shared volume
• Set tty to true

Example:

version: "3.8"

services:
  # Docs: https://docker-minecraft-server.readthedocs.io/en/latest/
  minecraft:
    image: itzg/minecraft-server
    stdin_open: true
    tty: true
    ports:
      - "25565:25565"
    environment:
      EULA: "TRUE"
      ...
    volumes:
      - ./mc-data:/data:z

[utsudashinou]

I'm not sure so far what it might be doing.

Can you provide more of the backup container logs surrounding that error?

Sorry, forget upload all logs. It is long, so upload here.

Thanks for checking the permission bits. Can you also check the owner of the world files it doesn't like? Use ls -ld to see if the numerical user ID owner matches up.

I executed ls -ld on some directories.

$ docker compose exec mc ls -ld
drwxrwxr-x 7 minecraft minecraft 4096 Jun 22 10:57 .
$ docker compose exec mc ls -ld world
drwxr-xr-x 12 minecraft minecraft 4096 Jul  2 14:43 world
$ docker compose exec backups ls -ld
drwxrwxrwx 2 500 users 4096 Jul  3 01:19 .
$ docker compose exec backups ls -ld /data
drwxrwxr-x 7 1000 1000 4096 Jun 22 10:57 /data
$ docker compose exec backups ls -ld /data/world
drwxr-xr-x 12 1000 1000 4096 Jul  2 14:43 /data/world

[itzg]

Thanks. I'm sorry, I meant to request the command ls -ln, with an "n" instead of "d", mainly

docker compose exec backups ls -ln /data/world

[utsudashinou]

@utsudashinou try to use:

chown 1000:1000 ../minecraft/ -R

Tips:

* Add `:z` to volumes to indicating shared volume

* Set `tty` to `true`

Example:

version: "3.8"

services:
  # Docs: https://docker-minecraft-server.readthedocs.io/en/latest/
  minecraft:
    image: itzg/minecraft-server
    stdin_open: true
    tty: true
    ports:
      - "25565:25565"
    environment:
      EULA: "TRUE"
      ...
    volumes:
      - ./mc-data:/data:z

I tried your solutions, unfortunately, it was a failure.

[utsudashinou]

Thanks. I'm sorry, I meant to request the command ls -ln, with an "n" instead of "d", mainly

docker compose exec backups ls -ln /data/world

Ok. Here you are.

$ docker compose exec backups ls -ln /data/world
total 156
drwxr-xr-x 6 1000 1000  4096 Jul  5  2023 DIM-1
drwxr-xr-x 6 1000 1000  4096 Jul  5  2023 DIM1
drwxr-xr-x 2 1000 1000  4096 Jul  2 05:19 advancements
drwxr-xr-x 2 1000 1000 12288 Jul  2 14:38 data
drwxr-xr-x 3 1000 1000  4096 Jul  5  2023 datapacks
drwxr-xr-x 2 1000 1000 32768 Jul  2 13:57 entities
-rw------- 1 1000 1000  1659 Jul  3 03:14 level.dat
-rw------- 1 1000 1000  1656 Jul  3 03:13 level.dat_old
drwxr-xr-x 2 1000 1000  4096 Jul  2 14:42 playerdata
drwxr-xr-x 2 1000 1000 28672 Jul  2 13:58 poi
drwxr-xr-x 2 1000 1000 36864 Jun 30 13:17 region
-rw-r--r-- 1 1000 1000     3 Jul  3 03:12 session.lock
drwxr-xr-x 2 1000 1000  4096 Jul  2 05:19 stats
-rw-r--r-- 1 1000 1000    16 Jul  5  2023 uid.dat

[itzg]

Try setting this to 1000 for the backup service

https://docs.docker.com/reference/compose-file/services/#user

[utsudashinou]

Try setting this to 1000 for the backup service

https://docs.docker.com/reference/compose-file/services/#user

Thank you! Backup completed!

But this setting is difficult to understand for me. I wish this thing would be documented.

[itzg]

But this setting is difficult to understand for me. I wish this thing would be documented.

Good point. I'll find a place to document and probably update the example to include it.