[SOLVED] Backup error permission denied

[HaZu]

Hi, I am currently setting up a PBS and trying to back up a container with a mapped drive. The Root Disk of the container is backed up fine, but my mount point is skipped. Doing the backup manually I get "INFO: failed to open file: "nextcloud": access denied" so it seems there is an issue with the permissions (obviously). Unfortunately I have no idea which permissions to set and where. The mount point is ZFS.

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Proxmox
Virtual Environment 7.4-3
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Container 106 (Nextcloud) on node 'homeserver'
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INFO: starting new backup job: vzdump 106 --storage pbs --node homeserver --notes-template '{{guestname}}' --remove 0 --mode snapshot
INFO: Starting Backup of VM 106 (lxc)
INFO: Backup started at 2023-04-05 18:28:27
INFO: status = running
INFO: CT Name: Nextcloud
INFO: including mount point rootfs ('/') in backup
INFO: including mount point mp1 ('/srv/nextcloud') in backup
INFO: backup mode: snapshot
INFO: ionice priority: 7
INFO: suspend vm to make snapshot
INFO: create storage snapshot 'vzdump'
  Logical volume "snap_vm-106-disk-0_vzdump" created.
INFO: resume vm
INFO: guest is online again after 2 seconds
INFO: creating Proxmox Backup Server archive 'ct/106/2023-04-05T16:28:27Z'
INFO: run: lxc-usernsexec -m u:0:100000:65536 -m g:0:100000:65536 -- /usr/bin/proxmox-backup-client backup --crypt-mode=none pct.conf:/var/tmp/vzdumptmp2979189_106/etc/vzdump/pct.conf root.pxar:/mnt/vzsnap0 --include-dev /mnt/vzsnap0/./ --include-dev /mnt/vzsnap0/./srv/nextcloud --skip-lost-and-found --exclude=/tmp/?* --exclude=/var/tmp/?* --exclude=/var/run/?*.pid --backup-type ct --backup-id 106 --backup-time 1680712107 --repository admin@pbs@192.168.1.24:backup1
INFO: Starting backup: ct/106/2023-04-05T16:28:27Z
INFO: Client name: homeserver
INFO: Starting backup protocol: Wed Apr  5 18:28:29 2023
INFO: Downloading previous manifest (Wed Apr  5 18:23:35 2023)
INFO: Upload config file '/var/tmp/vzdumptmp2979189_106/etc/vzdump/pct.conf' to 'admin@pbs@192.168.1.24:8007:backup1' as pct.conf.blob
INFO: Upload directory '/mnt/vzsnap0' to 'admin@pbs@192.168.1.24:8007:backup1' as root.pxar.didx
INFO: failed to open file: "nextcloud": access denied
INFO: root.pxar: had to backup 120.099 MiB of 4.353 GiB (compressed 19.609 MiB) in 35.39s
INFO: root.pxar: average backup speed: 3.394 MiB/s
INFO: root.pxar: backup was done incrementally, reused 4.236 GiB (97.3%)
INFO: Uploaded backup catalog (1.338 MiB)
INFO: Duration: 35.63s
INFO: End Time: Wed Apr  5 18:29:04 2023
INFO: adding notes to backup
INFO: cleanup temporary 'vzdump' snapshot
  Logical volume "snap_vm-106-disk-0_vzdump" successfully removed
INFO: Finished Backup of VM 106 (00:00:39)
INFO: Backup finished at 2023-04-05 18:29:06
INFO: Backup job finished successfully
TASK OK

 

[HaZu]

Just for all who stumble over the same issue: I granted the root User of the container read permission to the respective host zfs directory. This resolved the issue as vzdump of an unprivileged container runs as the root User of the LXC Container.