An integer between 1 and 7 that allows filtering messages based on the
severity level. The different severity levels supported by the Cisco ASA are:

[width="30%",cols="^1,2",options="header"]
|===========================
| log_level | severity
|     1     | Alert
|     2     | Critical
|     3     | Error
|     4     | Warning
|     5     | Notification
|     6     | Informational
|     7     | Debugging
|===========================

A value of 7 (default) will not filter any messages. A lower value will drop
any messages with a severity level higher than the specified value. For
example, `var.log_level: 3` will allow messages of level 1 (Alert), 2 (Critical)
and 3 (Error). All other messages will be dropped.

NOTE: The filtering is done in the ingest pipeline, if this setting is
changed, the ingest pipeline need to be reloaded manually. To reload
the ingest pipeline, set `filebeat.overwrite_pipelines: true` and
manually <<load-ingest-pipelines>>.