Alarm Logging Service¶
The alarm logging service records all alarm messages to create an archive of all alarm state changes and the associated actions.
This historical data can be used to:
Discover alarm patterns and trends
Generate Statistical reports on alarms
Debug the alarm system
Logged Alarm Messages¶
The alarm logging service creates kafka streams which can be configured to monitor one or more alarm topics. All associated with state change or configuration change are filtered, time stamped and added to an elastic index.
Examples:
Configuration changes
e.g. when new alarm nodes or pvs are added or removed or existing ones are enabled/disabled
State changes
e.g. alarm state changes from OK to MAJOR
Commands
e.g. a user actions to Acknowledge an alarm
Automatic purge of Elasticsearch indices¶
To avoid issues related to a high number of Elasticsearch indices, automatic purge can be enabled in order to delete
indices considered obsolete. This is done by setting the preferences date_span_units
and retain_indices_count
such
that they evaluate to a number larger or equal to 100. The default retain_indices_count
is 0, i.e. automatic purge is disabled by default.
The automatic purge is run using a cron expression defined in preference purge_cron_expr
, default is
0 0 0 * * SUN
, i.e. midnight each Sunday. See the SpringDocumentation on how to define the cron expression.
An Elasticsearch index is considered eligible for deletion if the last inserted message date is before current time
minus the number of days computed from date_span_units
and retain_indices_count
.