Libvirt Plugin: Automation

Bacula Enterprise Only

This solution is only available for Bacula Enterprise. For subscription inquiries, please reach out to sales@baculasystems.com.

The Libvirt Plugin performs several automated tasks - such as managing checkpoints and handling offline virtual machines—to ensure reliable and consistent operation. These automated behaviors are described in the sections below.

Starting Virtual Machines in Paused State

When the cold_backup parameter is enabled, the Libvirt Plugin starts virtual machines that are powered off at backup time in a paused state.

If the virtual machine remains paused throughout the backup, the plugin powers it off once the backup completes. However, if the virtual machine transitions to a state other than paused during the backup process, the plugin does not power it off and issues a warning instead.

Checkpoint Management

The Libvirt Plugin automatically manages checkpoints created during backup operations. Checkpoints are created when required and removed automatically once they are no longer needed for retention or restore operations.

LVM Unmount Handling

In certain environments, issues have been observed when backing up disks that use the Linux Logical Volume Manager (LVM). These issues are caused by LVM auto-scanning behavior: when the plugin attempts to disconnect a disk, it encounters errors. In such cases, the associated NBD device may become unusable, sometimes requiring a host reboot to recover.

To mitigate this issue, the plugin includes an automation that deactivates LVM before unmounting the NBD device. This mechanism is intentionally minimal and does not cover all possible scenarios. Bacula recommends using appropriate tools to disable such automount behavior.

Linux Permissions (DAC and MAC)

The plugin attempts to manage Linux permissions automatically, including Discretionary Access Control (DAC) and Mandatory Access Control (MAC). For more information, see this section.

If automatic permission handling is not desired, it can be disabled using the mandatory_access_control parameter.