Proxmox Backup Server No Subscription Update Repository

The Proxmox Backup Server provides different package repositories for installing updates. For production systems, Thomas-Krenn.AG recommends using a Proxmox Backup Server Subscription.

A valid subscription provides access to the extensively tested Enterprise Repository. Depending on the selected subscription level, technical support from Proxmox is also included. Purchasing a subscription also supports the continuous development of Proxmox Backup Server.

For test and development environments, the publicly available No-Subscription Repository can be used instead. It contains newer packages that have not yet undergone the same extensive testing and validation process as the packages in the Enterprise Repository. Therefore, the No-Subscription Repository is not recommended for production systems.

Error message without a valid subscription

After a default installation, the Enterprise Repository is enabled. If no valid subscription is configured, updating the package lists may result in an error similar to the following:

apt update

Err: https://enterprise.proxmox.com/debian/pbs trixie InRelease
  401 Unauthorized
E: Failed to fetch https://enterprise.proxmox.com/debian/pbs/dists/trixie/InRelease
E: The repository 'https://enterprise.proxmox.com/debian/pbs trixie InRelease' is not signed.

In this case, the Enterprise Repository must be disabled and the No-Subscription Repository must be configured.

The following configuration applies to Proxmox Backup Server 4.x based on Debian 13 “Trixie”.

Disable the Enterprise Repository

By default, the Enterprise Repository is configured in the following file:

/etc/apt/sources.list.d/pbs-enterprise.sources

The file can be opened using an editor such as nano:

nano /etc/apt/sources.list.d/pbs-enterprise.sources

The default repository configuration looks similar to the following:

Types: deb
URIs: https://enterprise.proxmox.com/debian/pbs
Suites: trixie
Components: pbs-enterprise
Signed-By: /usr/share/keyrings/proxmox-archive-keyring.gpg

To disable the Enterprise Repository, add the following line:

Enabled: false

The complete file should then look as follows:

Types: deb
URIs: https://enterprise.proxmox.com/debian/pbs
Suites: trixie
Components: pbs-enterprise
Signed-By: /usr/share/keyrings/proxmox-archive-keyring.gpg
Enabled: false

Alternatively, the repository file can be removed:

rm /etc/apt/sources.list.d/pbs-enterprise.sources

Disabling the repository configuration is generally preferable, as it can easily be enabled again later.

Configure the No-Subscription Repository

Create or edit the following file:

nano /etc/apt/sources.list.d/proxmox.sources

Add the following content:

Types: deb
URIs: http://download.proxmox.com/debian/pbs
Suites: trixie
Components: pbs-no-subscription
Signed-By: /usr/share/keyrings/proxmox-archive-keyring.gpg

Alternatively, the file can be created directly from the command line:

cat > /etc/apt/sources.list.d/proxmox.sources << 'EOF'
Types: deb
URIs: http://download.proxmox.com/debian/pbs
Suites: trixie
Components: pbs-no-subscription
Signed-By: /usr/share/keyrings/proxmox-archive-keyring.gpg
EOF

Verify the repository configuration

Update the package lists:

apt update

The configured package repositories can be checked using the following command:

apt policy

The output should include the No-Subscription Repository for Debian 13 “Trixie”. The Enterprise Repository should no longer be queried.

The system can then be updated:

apt update
apt full-upgrade

After kernel updates or other system-level updates, the Proxmox Backup Server should be restarted:

reboot

Check for outdated repository files

After upgrading from Proxmox Backup Server 3 to Proxmox Backup Server 4, repository entries for Debian 12 “Bookworm” may still be present.

All configured repository files can be checked using the following command:

grep -R --line-number --extended-regexp \
  'bookworm|trixie|enterprise\.proxmox|download\.proxmox' \
  /etc/apt/sources.list \
  /etc/apt/sources.list.d/ 2>/dev/null

Outdated entries containing bookworm must be removed or disabled. Repository entries for different Debian releases must not be mixed.