I’m trying to use proxmox-backup-client from an external Debian server (Netcup/Contabo) to send backups to a central Proxmox Backup Server (PBS). The PBS is placed behind an Nginx Proxy Manager and is accessible via HTTPS at backup.REDACTED:443.
The client machine is not a Proxmox VE host, it’s just a standard Debian with the PBS client. The goal is to back up the Linux server into the PBS datastore.
The manual command we use is:
<span><span>proxmox-backup-client backup </span><span><span>"manual-<span>$(date +%F)</span></span></span><span>.pxar:/" \<br> --repository </span><span><span>'root@REDACTED'</span></span><span> \<br> --exclude /proc --exclude /sys --exclude /dev --exclude /run \<br> --exclude /mnt --exclude /media<br></span></span>
The problem is that, although it worked once, most of the time we get:
<span><span><span>Starting</span></span><span> backup protocol...<br></span><span><span>Error</span></span><span>: permission check failed.<br></span></span>
We have tried several approaches: running via cron, setting environment variables, using an API token with datastore permissions, even granting temporary Admin privileges, but the result is always the same. The PBS GUI works fine, but from external Linux clients (through the reverse proxy) the backup consistently fails.
So the main question is: is this scenario officially supported (external Linux servers → PBS behind an Nginx Proxy Manager reverse proxy)?
And if so, what are the minimal required privileges for the user/token so that proxmox-backup-client backup works without “permission check failed” errors?
The client machine is not a Proxmox VE host, it’s just a standard Debian with the PBS client. The goal is to back up the Linux server into the PBS datastore.
The manual command we use is:
<span><span>proxmox-backup-client backup </span><span><span>"manual-<span>$(date +%F)</span></span></span><span>.pxar:/" \<br> --repository </span><span><span>'root@REDACTED'</span></span><span> \<br> --exclude /proc --exclude /sys --exclude /dev --exclude /run \<br> --exclude /mnt --exclude /media<br></span></span>
The problem is that, although it worked once, most of the time we get:
<span><span><span>Starting</span></span><span> backup protocol...<br></span><span><span>Error</span></span><span>: permission check failed.<br></span></span>
We have tried several approaches: running via cron, setting environment variables, using an API token with datastore permissions, even granting temporary Admin privileges, but the result is always the same. The PBS GUI works fine, but from external Linux clients (through the reverse proxy) the backup consistently fails.
So the main question is: is this scenario officially supported (external Linux servers → PBS behind an Nginx Proxy Manager reverse proxy)?
And if so, what are the minimal required privileges for the user/token so that proxmox-backup-client backup works without “permission check failed” errors?
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