[SOLVED] [NFS] Permission denied on second network during backup

[Bristow]

Hello to all !

I currently have a Proxmox 7.0-8 which allows me to host different services, and in particular services on the students' LAN (FOG) but also virtual machines on a LAN DMZ so that they can be accessed from outside. So I have 2 network interfaces on Proxmox.

I also have a huge Synology NAS on which I want to do all my backups. I created two volumes Sauvegardes and Sauvegardes221 and I exported these volumes on my 2 networks of Proxmox via an NFS export.
I can see my 2 storages on my Proxmox (I put a network interface on each network on the NAS side).

The problem is that the backups on the student LAN work, but not on the DMZ. I have a Permission Denied when creating the backup archive. I am aware that having different legs on networks is not a great approach, but we do the best in education...

INFO: create storage snapshot 'vzdump'
  Logical volume "snap_vm-101-disk-0_vzdump" created.
INFO: creating vzdump archive '/mnt/pve/Nas-NFS221/dump/vzdump-lxc-101-2021_10_11-14_09_06.tar.zst'
INFO: tar: /mnt/pve/Nas-NFS221/dump/vzdump-lxc-101-2021_10_11-14_09_06.tmp: Cannot open: Permission denied
INFO: tar: Error is not recoverable: exiting now
INFO: cleanup temporary 'vzdump' snapshot

Do you know what could prevent these backups?

Thanks a lot !

 

[Dunuin]

If you try to backup a unprivileged LXC you need to take the user-remapping into account. Your LXCs root user needs access to the share and that should be mapped to UID 100000. So you could...
1.) set your NFS share to chmod 777 so eberyone has full access
2.) allow UID 100000 to write to the share
3.) edit your /etc/vzdump.conf and point the tmpdir to a local folder with 777 rights like "/tmp".

If its not a unprivileged LXC you possibly did something wrong on the NAS side.

 

[Bristow]

Thanks @Dunuin

I have edited my /etc/vzdump.conf and point the tmpdir to the local folder /tmp.

 

[ladidadi]

Hi,

I have the same issue, seems like tmp is being locked while backing it up....Did you had to do for the whole cluster hosts or just the one that was causing issues?

 

[Bristow]

I did it on my proxmox, so, on all the LXC... I didn't notice any particular problem.

 

[Polygon9881]

Thanks @Dunuin

I have edited my /etc/vzdump.conf and point the tmpdir to the local folder /tmp.

Had the same issue, this fixed it!

 

[alexskysilk]

I have edited my /etc/vzdump.conf and point the tmpdir to the local folder /tmp.

Careful doing this. on a large source file system you may overrun your local storage. To prevent this from killing your host, either put limits (quotas) on the total usage of /tmp, or move /tmp to its own file system.