Sun SNMP Management Agent for Sun Fire and Netra Systems

This chapter describes the properties and function of traps.

The chapter contains the following sections:

• Overview
• Standard Trap Properties
• Trap Types

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Overview

The SNMP agent provides traps to provide asynchronous updates to management applications. The agent provides notifications for the following:

• Change of value within an object
• Removal of an object from the management model
• Addition of an object to the management model
• Raising of an error or warning condition against a component within the model
• Clearance of an error or warning condition

The SNMP agent determines whether an error or warning condition exists against an object based on any sensors related to that object and/or any sub components of that object. For example, a CPU can have an associated fan and the fan can have an associated tachometer. All three components have an ability to report their operational status. If the tachometer reports that it has a failed operational status, this relates only to the health of the tachometer.

However if the tachometer reports that the speed of the fan has fallen below a particular threshold, a trap is raised against the fan rather than the tachometer. At this point the CPU may be still be completely functional. If the CPU has a related temperature sensor and the fan continues to fail to function, the temperature could rise. If, at some point, the temperature exceeds a threshold value, a fault is issued against the CPU.

Multiple thresholds can be set for all numeric sensors:

• upperFatal
• upperCritical
• upperNonCritical
• lowerFatal
• lowerCritical
• lowerNonCritical

The precise semantics of these thresholds depends on the underlying component and not all components use all the thresholds. Where a component uses a threshold, the agent always creates a trap when the threshold is crossed. This means that if the current value reported by the sensor changes dramatically and crosses multiple thresholds at the same time, multiple traps are delivered.

You can determine the threshold values assigned to a numeric sensor by reading the following properties:

• sunPlatNumericSensorLowerThresholdNonCritical
• sunPlatNumericSensorUpperThresholdNonCritical
• sunPlatNumericSensorLowerThresholdCritical
• sunPlatNumericSensorUpperThresholdCritical
• sunPlatNumericSensorLowerThresholdFatal
• sunPlatNumericSensorUpperThresholdFatal

These are all 32 bit integer values, the actual numeric threshold being determined by applying the exponent value provided by sunPlatNumericSensorExponent.

For binary sensors, a trap is sent when the value reported by sunPlatBinarySensorCurrent is not the same as that specified by sunPlatBinarySensorExpected. A trap indicating the problem has cleared is sent when sunPlatBinarySensorCurrent returns to the same value as sunPlatBinarySensorExpected.

For any binary sensor, you can determine the precise semantics of the reported values from the descriptions supplied by sunPlatBinarySensorInterpretTrue and sunPlatBinarySensorInterpretFalse.

To configure the agent to send traps to a particular management application please see Chapter 3.

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Standard Trap Properties

The information communicated in traps generated by the agent is based on a common set of attributes. For clarity, the sunPlatNotification prefix has been omitted from the following attribute names:

• EventId

This is an integer uniquely identifying the notification and an indication of the order in which the notifications were generated by the agent.

• Time

This is a timestamp indicating the time at which the notification was generated.

• Object

This attribute is an OID that provides a direct reference to an entry in the MIB representing the resource with which the event is associated.

• CorrelatedNotifications

This attribute is comma-separated list of ID values that identify the other events to which this event is associated.

• AdditionalInfo

This attribute provides an additional OID that further qualifies the purpose of the trap. Not all traps populate this value, and a value of 0.0 identifies that no trap specific value is relevant to the trap.

• AdditionalText

This attribute provides a further textual description for the trap. The exact content of the string varies depending on the cause of the trap. However, the format used for this string is always of the form:

<serial number>/<hostname>/<entPhysicalName>:<trap specific text>

where entPhysicalName identifies the physical name of the object raising the trap.

Examples of the <trap specific text> include:

• Voltage threshold crossed
• Current threshold crossed
• Tachometer threshold crossed
• Temperature threshold

• PerceivedSeverity

This attribute describes the severity of the cause of the trap. The attribute can take the following values:

• indeterminate(1)
• critical(2)
• major(3)
• minor(4)
• warning(5)
• cleared(6)

• ProbableCause

This attribute provides a textual description of the probable cause.

Example of the permitted values include:

• lowTemperature
• coolingSystemFailure
• externalEquipmentFailure

• SpecificProblem

This attribute provides an additional textual description that supplies further information about the cause of the trap.

• RepairAction

This attribute provides a textual description of the potential repair actions. Multiple repair actions may be described, in which case <CR><LF> sequences are used to delimit individual descriptions of the actions.

• ChangedOID

This attribute provides the OID of an object whose value changing caused the trap to be sent

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Trap Types

This section describes the function and properties of the following trap types:

• Object creation and deletion traps
• Property change traps
• Environmental and status alarm traps

Object Creation and Deletion Traps

The sunPlatObjectCreation trap is sent when an object is created within the agent to represent a new component. For example, a new component has been hotplugged into the system. The agent sends object creation traps only for objects added once it has started, so traps are not generated during the initial phase of discovery when the agent first starts.

The sunPlatObjectDeletion trap is sent when an object is deleted as a result of a component being removed or unconfigured from the system. Object creation and deletion traps have the following properties:

• EventId

This attribute is set as described in Standard Trap Properties.

• Time

This attribute is set as described in Standard Trap Properties.

• Object

The attribute is OID of the parent of the object being created or deleted. The OID is that of the entPhysicalDescr object for the row in entPhysicalTable that represents the parent object.

• CorrelatedNotifications

This is currently assigned to an empty string.

• AdditionalInfo

This attribute is the OID of object being created. The OID is that of the entPhysicalDescr object for the row in entPhysicalTable being created.

• AdditionalText

For details, see Standard Trap Properties.

Property Change Traps

The agent can deliver traps whenever a value in an object changes. The type of trap depends on the type of the object:

• The sunPlatStateChange trap is sent when a state attribute changes value.
• The sunPlatAttributeChangeInteger trap is sent when the value of an integer property changes. This trap is used for all integer property value changes, with the exception of current values with respect to numeric sensors as such values can change rapidly and can result in a large number of traps.
• The sunPlatAttributeChangeString trap is sent when the value of a string property changes. This trap is used for all string property value changes.
• The sunPlatAttributeChangeOID trap is sent when the value of an OID property changes. This trap is used for all OID property value changes.

Depending on the object type causing the trap, different attributes in the trap body are used to supply both before and after values of the changed attribute:

• OldInteger

This attribute is used for sunPlatStateChange and sunPlatAttributeChangeInteger traps. The attribute provides the original value of the object identified by sunPlatNotificationChangedOID.

• NewInteger

This attribute is used for sunPlatStateChange and sunPlatAttributeChangeInteger traps. The attribute provides the new value of the object identified by sunPlatNotificationChangedOID.

• OldString

This attribute is used by the sunPlatAttributeChangeString trap. This is the original value of the object identified by sunPlatNotificationChangedOID.

• NewString

This attribute is used by the sunPlatAttributeChangeString trap. This is the new value of the object identified by sunPlatNotificationChangedOID.

• OldOID

This attribute is used by the sunPlatAttributeChangeOID trap. This is the original value of the object identified by sunPlatNotificationChangedOID.

• NewOID

This attribute is used by the sunPlatAttributeChangeOID trap. This is the new value of the object identified by sunPlatNotificationChangedOID.

Environmental and Status Alarm Traps

The agent sends traps to report potential environmental problems and other warning or error conditions. The definition of environmental, or other, condition depends on the component, but examples include the speed of a fan dropping below a pre-determined threshold and the temperature of a component rising above a threshold.

Sensors, such as numeric sensors, have multiple thresholds defined to reflect warning, critical and failure conditions. If a sensor value crosses multiple thresholds when sampled, traps are sent for all thresholds that have been crossed. Similarly, when the reading provided by the sensor returns to a value within an acceptable range, trap(s) are sent to indicate that the warning or error condition has cleared.

The traps used by the agent are:

• sunPlatCommunicationsAlarm
• sunPlatEnvironmentalAlarm
• sunPlatEquipmentAlarm
• sunPlatProcessingErrorAlarm

The trap used depends on the nature of the problem as defined by the generic network information model (ITU-T Recommendation M.3100). The attributes supplied by the traps are:

• EventId

This attribute is set as described in Standard Trap Properties.

• Time

This attribute is set as described in Standard Trap Properties.

• Object

This attribute is set as described in Standard Trap Properties.

• CorrelatedNotifications

This attribute is assigned an empty string when an alarm is first raised. When the alarm condition is cleared, the value is the string representation of the sunPlatNotificationEventId value that was sent in the trap when the alarm condition was first raised.

• AdditionalInfo

This attribute is set as described in Standard Trap Properties.

• AdditionalText

This attribute is set as described in Standard Trap Properties.

• PerceivedSeverity

This attribute is set as described in Standard Trap Properties.

• ProbableCause

This attribute is set as described in Standard Trap Properties.

• SpecificProblem

This attribute is set as described in Standard Trap Properties.

• RepairAction

This attribute is set as described in Standard Trap Properties.

Sun SNMP Management Agent for Sun Fire and Netra Systems

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Copyright © 2006, Sun Microsystems, Inc. All Rights Reserved.