An alarm represents a stateful condition of the server or a resource that might indicate
a problem, such as low disk space or external server unavailability. A gauge defines a
set of threshold values with a specified severity that, when crossed, cause the server
to enter or exit an alarm state. Gauges are used for monitoring continuous values like
CPU load or free disk space (Numeric Gauge), or an enumerated set of values such as
'server available' or ‘server unavailable’ (Indicator Gauge). Gauges generate alarms,
when the gauge’s severity changes because of changes in the monitored value. Like
alerts, alarms have severity (NORMAL, WARNING, MINOR, MAJOR, CRITICAL), name, and
message. Alarms will always have a Condition
property, and can have a
Specific Problem or Resource property. If surfaced through SNMP, a
ProbableCause
property and AlarmType
property are
also listed. Alarms can be configured to generate alerts when the alarm's severity
changes.
There are two alert types supported by the server - standard and alarm-specific. The
server constantly monitors for conditions that might need attention by administrators,
such as low disk space. For this condition, the standard alert is
low-disk-space-warning
, and the alarm-specific alert is
alarm-warning
. The server can be configured to generate
alarm-specific alerts instead of, or in addition to, standard alerts. By default,
standard alerts are generated for conditions internally monitored by the server.
However, gauges can only generate alarm-alerts.
The server installs a set of gauges that are specific to the product and that can be cloned or configured through the dsconfig tool. Existing gauges can be tailored to fit each environment by adjusting the update interval and threshold values. Configuration of system gauges determines the criteria by which alarms are triggered. The Stats Logger can be used to view historical information about the value and severity of all system gauges.
PingDirectory servers are compliant with the International
Telecommunication Union CCITT Recommendation X.733 (1992) standard for generating and
clearing alarms. If configured, entering or exiting an alarm state can result in one or
more alerts. An alarm state is exited when the condition no longer applies. An
alarm_cleared
alert type is generated by the system when an alarm's
severity changes from a non-normal severity to any other severity. An
alarm_cleared
alert will correlate to a previous alarm when
Condition and Resource property are the same. The Alarm Manager, which governs the
actions performed when an alarm state is entered, is configurable through the
dsconfig tool and Administrative Console.
Like the Alerts Backend, which stores information in cn=alerts
, the
Alarm Backend stores information within the cn=alarms
backend. Unlike
alerts, alarm thresholds have a state over time that can change in severity and be
cleared when a monitored value returns to normal. Alarms can be viewed with the
status tool. As with other alert types, alert handlers can be
configured to manage the alerts generated by alarms. A complete listing of system
alerts, alarms, and their severity is available in
<server-root>/docs/admin-alerts-list.csv.