PBS Post Install Scripts breaks PBS LXC

[hsb-tonmoy]

✅ Have you read and understood the above guidelines?

yes

🔎 Did you run the script with verbose mode enabled?

Yes, verbose mode was enabled and the output is included below

📜 What is the name of the script you are using?

PBS Post Install

📂 What was the exact command used to execute the script?

bash -c "$(curl -fsSL https://raw.githubusercontent.com/community-scripts/ProxmoxVE/main/tools/pve/post-pbs-install.sh)"

⚙️ What settings are you using?

• Default Settings
• Advanced Settings

🖥️ Which Linux distribution are you using?

Debian 13

📈 Which Proxmox version are you on?

pve-manager/9.1.2/9d436f37a0ac4172 (running kernel: 6.17.2-1-pve)

📝 Provide a clear and concise description of the issue.

I got PBS installed as an unprivileged LXC using the script. I was able to access the GUI, SSH into it right after the installation. Then I ran the PBS Post Install script, said yes to all the prompts, rebooted the LXC and now it's inaccessible through all paths. The web GUI won't load, ssh just hangs there. Even the LXC console connects but shows a blank screen.

I'm able to connect to it through pct enter and I see the following outputs:

root@pbs:~# systemctl status proxmox-backup-proxy.service
○ proxmox-backup-proxy.service - Proxmox Backup API Proxy Server
     Loaded: loaded (/usr/lib/systemd/system/proxmox-backup-proxy.service; enabled; preset: enabled)
     Active: inactive (dead)
        Job: 125

root@pbs:~# journalctl -b -u proxmox-backup-proxy.service
-- No entries --

root@pbs:~# journalctl -u proxmox-backup-proxy.service
Dec 06 12:16:46 pbs systemd[1]: Stopping proxmox-backup-proxy.service - Proxmox Backup API Proxy Server...
Dec 06 12:16:46 pbs systemd[1]: proxmox-backup-proxy.service: Deactivated successfully.
Dec 06 12:16:46 pbs systemd[1]: Stopped proxmox-backup-proxy.service - Proxmox Backup API Proxy Server.

root@pbs:~# systemctl  status proxmox-backup.service
○ proxmox-backup.service - Proxmox Backup API Server
     Loaded: loaded (/usr/lib/systemd/system/proxmox-backup.service; enabled; preset: enabled)
     Active: inactive (dead)
        Job: 122
root@pbs:~# systemctl start proxmox-backup.service

Attempting to start proxmox-backup.service or proxmox-backup-proxy.service just hangs there.

🔄 Steps to reproduce the issue.

1. Install PBS as an unprivileged LXC using Proxmox Backup Server (PBS) script:
   bash -c "$(curl -fsSL https://raw.githubusercontent.com/community-scripts/ProxmoxVE/main/ct/proxmox-backup-server.sh)"
2. Run PBS Post Install script on it

❌ Paste the full error output (if available).

Dec 06 12:30:32 pbs systemd-journald[46]: Journal started
Dec 06 12:30:32 pbs systemd-journald[46]: Runtime Journal (/run/log/journal/5fbcc645c003408a83ba2deb03dded9d) is 8M, max 637.3M, 629.3M free.
Dec 06 12:30:32 pbs systemd-modules-load[47]: Failed to find module 'zfs'
Dec 06 12:30:32 pbs lvm[41]:   /dev/mapper/control: mknod failed: Operation not permitted
Dec 06 12:30:32 pbs lvm[41]:   Failure to communicate with kernel device-mapper driver.
Dec 06 12:30:32 pbs lvm[41]:   Check that device-mapper is available in the kernel.
Dec 06 12:30:32 pbs lvm[41]:   Incompatible libdevmapper 1.02.205 (2025-02-27) and kernel driver (unknown version).
Dec 06 12:30:32 pbs systemd[1]: Finished nftables.service - nftables.
Dec 06 12:30:32 pbs systemd[1]: Finished systemd-tmpfiles-setup-dev-early.service - Create Static Device Nodes in /dev gracefully.
Dec 06 12:30:32 pbs systemd[1]: Reached target network-pre.target - Preparation for Network.
Dec 06 12:30:32 pbs systemd[1]: Starting systemd-journal-flush.service - Flush Journal to Persistent Storage...
Dec 06 12:30:32 pbs systemd[1]: systemd-sysusers.service - Create System Users was skipped because no trigger condition checks were met.
Dec 06 12:30:32 pbs systemd[1]: systemd-timesyncd.service - Network Time Synchronization was skipped because of an unmet condition check (ConditionVirtualization=!container).
Dec 06 12:30:32 pbs systemd[1]: Reached target time-set.target - System Time Set.
Dec 06 12:30:32 pbs systemd[1]: Starting systemd-tmpfiles-setup-dev.service - Create Static Device Nodes in /dev...
Dec 06 12:30:32 pbs systemd[1]: Finished systemd-sysctl.service - Apply Kernel Variables.
Dec 06 12:30:32 pbs systemd[1]: Finished lvm2-monitor.service - Monitoring of LVM2 mirrors, snapshots etc. using dmeventd or progress polling.
Dec 06 12:30:32 pbs systemd-journald[46]: Time spent on flushing to /var/log/journal/5fbcc645c003408a83ba2deb03dded9d is 501us for 17 entries.
Dec 06 12:30:32 pbs systemd-journald[46]: System Journal (/var/log/journal/5fbcc645c003408a83ba2deb03dded9d) is 16M, max 3.9G, 3.8G free.
Dec 06 12:30:32 pbs systemd[1]: Finished systemd-tmpfiles-setup-dev.service - Create Static Device Nodes in /dev.
Dec 06 12:30:32 pbs systemd[1]: Reached target local-fs-pre.target - Preparation for Local File Systems.
Dec 06 12:30:32 pbs systemd[1]: systemd-udevd.service - Rule-based Manager for Device Events and Files was skipped because of an unmet condition check (ConditionPathIsReadWrite=/sys).
Dec 06 12:30:32 pbs systemd[1]: Finished systemd-journal-flush.service - Flush Journal to Persistent Storage.
Dec 06 12:30:33 pbs systemd[1]: Mounting run-proxmox\x2dbackup.mount - Mount tmpfs at /run/proxmox-backup...
Dec 06 12:30:33 pbs systemd[1]: Mounted run-proxmox\x2dbackup.mount - Mount tmpfs at /run/proxmox-backup.
Dec 06 12:30:42 pbs zfs[59]: /dev/zfs and /proc/self/mounts are required.
Dec 06 12:30:42 pbs zfs[59]: Try running 'udevadm trigger' and 'mount -t proc proc /proc' as root.
Dec 06 12:30:42 pbs systemd[1]: zfs-mount.service: Main process exited, code=exited, status=1/FAILURE
Dec 06 12:30:42 pbs systemd[1]: zfs-mount.service: Failed with result 'exit-code'.
Dec 06 12:30:42 pbs systemd[1]: Failed to start zfs-mount.service - Mount ZFS filesystems.
Dec 06 12:30:42 pbs systemd[1]: Reached target local-fs.target - Local File Systems.
Dec 06 12:30:42 pbs zvol_wait[77]: /dev/zfs and /proc/self/mounts are required.
Dec 06 12:30:42 pbs zvol_wait[77]: Try running 'udevadm trigger' and 'mount -t proc proc /proc' as root.
Dec 06 12:30:42 pbs zvol_wait[60]: No zvols found, nothing to do.
Dec 06 12:30:42 pbs systemd[1]: Listening on systemd-sysext.socket - System Extension Image Management.
Dec 06 12:30:42 pbs systemd[1]: Starting networking.service - Network initialization...
Dec 06 12:30:42 pbs systemd[1]: Starting pbs-network-config-commit.service - Commit any pending Proxmox Backup Server network changes...
Dec 06 12:30:42 pbs systemd[1]: Starting proxmox-backup-banner.service - Proxmox Backup Server Login Banner...
Dec 06 12:30:42 pbs systemd[1]: systemd-binfmt.service - Set Up Additional Binary Formats was skipped because of an unmet condition check (ConditionPathIsMountPoint=/proc/sys/fs/binfmt_misc).
Dec 06 12:30:42 pbs systemd[1]: systemd-confext.service - Merge System Configuration Images into /etc/ was skipped because no trigger condition checks were met.
Dec 06 12:30:42 pbs systemd[1]: systemd-sysext.service - Merge System Extension Images into /usr/ and /opt/ was skipped because no trigger condition checks were met.
Dec 06 12:30:42 pbs systemd[1]: Starting systemd-tmpfiles-setup.service - Create System Files and Directories...
Dec 06 12:30:42 pbs systemd[1]: Finished zfs-volume-wait.service - Wait for ZFS Volume (zvol) links in /dev.
Dec 06 12:30:42 pbs systemd[1]: Reached target zfs-volumes.target - ZFS volumes are ready.
Dec 06 12:30:42 pbs systemd[1]: Finished pbs-network-config-commit.service - Commit any pending Proxmox Backup Server network changes.
Dec 06 12:30:42 pbs systemd[1]: Finished proxmox-backup-banner.service - Proxmox Backup Server Login Banner.
Dec 06 12:30:42 pbs systemd-tmpfiles[94]: /usr/lib/tmpfiles.d/legacy.conf:14: Duplicate line for path "/run/lock", ignoring.
Dec 06 12:30:42 pbs networking[91]: networking: Configuring network interfaces
Dec 06 12:30:42 pbs systemd[1]: Finished systemd-tmpfiles-setup.service - Create System Files and Directories.
Dec 06 12:30:42 pbs systemd[1]: ldconfig.service - Rebuild Dynamic Linker Cache was skipped because no trigger condition checks were met.
Dec 06 12:30:42 pbs systemd[1]: systemd-firstboot.service - First Boot Wizard was skipped because of an unmet condition check (ConditionFirstBoot=yes).
Dec 06 12:30:42 pbs systemd[1]: first-boot-complete.target - First Boot Complete was skipped because of an unmet condition check (ConditionFirstBoot=yes).
Dec 06 12:30:42 pbs systemd[1]: systemd-journal-catalog-update.service - Rebuild Journal Catalog was skipped because of an unmet condition check (ConditionNeedsUpdate=/var).
Dec 06 12:30:42 pbs systemd[1]: systemd-machine-id-commit.service - Save Transient machine-id to Disk was skipped because of an unmet condition check (ConditionPathIsMountPoint=/etc/machine-id).
Dec 06 12:30:42 pbs systemd[1]: systemd-update-done.service - Update is Completed was skipped because no trigger condition checks were met.
Dec 06 12:30:42 pbs systemd[1]: Reached target sysinit.target - System Initialization.
Dec 06 12:30:42 pbs systemd[1]: Started postfix-resolvconf.path - Watch for resolv.conf updates for postfix.
Dec 06 12:30:42 pbs systemd[1]: Started apt-daily.timer - Daily apt download activities.
Dec 06 12:30:42 pbs systemd[1]: Started apt-daily-upgrade.timer - Daily apt upgrade and clean activities.
Dec 06 12:30:42 pbs systemd[1]: Started apt-listchanges.timer - Try hourly to initialize apt-listchanges database for APT.
Dec 06 12:30:42 pbs systemd[1]: Started dpkg-db-backup.timer - Daily dpkg database backup timer.
Dec 06 12:30:42 pbs systemd[1]: Started e2scrub_all.timer - Periodic ext4 Online Metadata Check for All Filesystems.
Dec 06 12:30:42 pbs systemd[1]: fstrim.timer - Discard unused filesystem blocks once a week was skipped because of an unmet condition check (ConditionVirtualization=!container).
Dec 06 12:30:42 pbs systemd[1]: Started logrotate.timer - Daily rotation of log files.
Dec 06 12:30:42 pbs systemd[1]: Started man-db.timer - Daily man-db regeneration.

🖼️ Additional context (optional).

No response

[MickLesk]

Cant reproduce it. Fresh Install, add Post Install after success, reboot, Work all fine. Can you deliver an journalctl?

[MickLesk]

Ive investigate a little bit deeper;
The issue is not with the post-install script itself. The problem is that the PBS is running in an unprivileged LXC container

After apt dist-upgrade the ZFS kernel modules are pulled in as dependencies. However, in an unprivileged container:

• No access to /dev/zfs
• No kernel module loading (Failed to find module 'zfs')
• No device-mapper access (mknod failed: Operation not permitted)

The proxmox-backup-proxy.service depends on zfs-mount.service which fails, causing the whole service chain to hang.

Soltion for you:

• Use a privileged LXC for PBS (recommended for production and in combination with zfs)
  Or:
  -Disable ZFS services in the unprivileged container:

  systemctl mask zfs-mount.service zfs-import-cache.service zfs-import-scan.service
  systemctl restart proxmox-backup-proxy

``