When auditd notices that free disk space on its logging partition is low, it
will trigger the ``space_left_action``. The threshold of remaining disk space
is configured by ``space_left`` in ``/etc/audit/auditd.conf``.

By default, Ubuntu sets this value to 75 megabytes. The STIG doesn't set a
specific requirement for the exact size, so the Ansible task will ensure that
the Ubuntu default of 75 megabytes is set.