Strange backup error on NFS storage on only one LXC container

openaspace

Well-Known Member
Sep 16, 2019
486
13
58
Italy
Strange backup error on NFS storage on only one LXC container:

Code:
2021-10-19 22:17:17 INFO: Starting Backup of VM 101 (lxc)
2021-10-19 22:17:17 INFO: status = running
2021-10-19 22:17:17 INFO: CT Name: alphine-proxy
2021-10-19 22:17:17 INFO: including mount point rootfs ('/') in backup
2021-10-19 22:17:17 INFO: backup mode: snapshot
2021-10-19 22:17:17 INFO: ionice priority: 7
2021-10-19 22:17:17 INFO: create storage snapshot 'vzdump'
2021-10-19 22:17:17 INFO: creating vzdump archive '/mnt/pve/synology/dump/vzdump-lxc-101-2021_10_19-22_17_17.tar.lzo'
2021-10-19 22:17:18 INFO: tar: /mnt/pve/synology/dump/vzdump-lxc-101-2021_10_19-22_17_17.tmp: Cannot open: Permission denied
2021-10-19 22:17:18 INFO: tar: Error is not recoverable: exiting now
2021-10-19 22:17:18 INFO: cleanup temporary 'vzdump' snapshot
2021-10-19 22:17:18 ERROR: Backup of VM 101 failed - command 'set -o pipefail && lxc-usernsexec -m u:0:100000:65536 -m g:0:100000:65536 -- tar cpf - --totals --one-file-system -p --sparse --numeric-owner --acls --xattrs '--xattrs-include=user.*' '--xattrs-include=security.capability' '--warning=no-file-ignored' '--warning=no-xattr-write' --one-file-system '--warning=no-file-ignored' '--directory=/mnt/pve/synology/dump/vzdump-lxc-101-2021_10_19-22_17_17.tmp' ./etc/vzdump/pct.conf ./etc/vzdump/pct.fw '--directory=/mnt/vzsnap0' --no-anchored '--exclude=lost+found' --anchored '--exclude=./tmp/?*' '--exclude=./var/tmp/?*' '--exclude=./var/run/?*.pid' ./ | lzop >/mnt/pve/synology/dump/vzdump-lxc-101-2021_10_19-22_17_17.tar.dat' failed: exit code 2
 
hi,

Code:
2021-10-19 22:17:18 INFO: tar: /mnt/pve/synology/dump/vzdump-lxc-101-2021_10_19-22_17_17.tmp: Cannot open: Permission denied

when you make a backup of an unprivileged container, the backup is executed in the context of the unprivileged user (which doesn't have write-permission on your NFS share)

you can set a tmpdir variable in the /etc/vzdump.conf file to a world-writable location and then it should work :)