Backup container fails to start

[cburza]

When using mcbackup, the backup container fails to start with:

level=fatal msg="Failed to run sub-command" error="fork/exec /usr/bin/backup: operation not permitted".

My Helm values:

mcbackup:
  enabled: true
  persistence:
    annotations:
      nfs.io/storage-path: minecraft-backups
    storageClass: deimos-nfs

    backupDir:
      enabled: true
      Size: 5Gi

I checked and I have the following permissions set for the backups directory:
drwxrwxrwx 1 1000 2000 6 Jan 12 05:55 backups

I have not been able to get the backup container to run unless I make the runAsUser root:

securityContext:
    runAsUser: 0

Is there perhaps another way? Or should the Helm chart allow us to set the run as user as root?

I assume the issue is in entrypoint-demoter that tries to change the user which runs the backup command.

setCredentials(uid, gid, command)

[cburza]

Or perhaps not use entrypoint-demoter at all and run the backup script directly?

[itzg]

Your suggestion about entrypoint-demoter was very helpful. It wasn't skipping the "demoting" when the current user wasn't root. I have a test image to try out by setting mcbackup.imageTag to "test-skip-non-root".

[jesseops]

@itzg this tag does appear to do the trick for me:

bash-5.1$ ls -lah /backups/
total 264M
drwxrwsr-x 3 root 2000 4.0K Feb  1 06:21 .
drwxr-xr-x 1 root root 4.0K Feb  1 06:19 ..
drwxrws--- 2 root 2000  16K Jan 22 23:52 lost+found
-rw-r--r-- 1 1000 2000 264M Feb  1 06:22 minecraft-with-friends-dwarven-fortress-20220201-062148.tgz

[itzg]

The latest itzg/mc-backup image now includes the fix.