SNMP trap event handler

The SNMP trap event handler sends alert messages as SNMP traps.

Configuration

Configuration as well as default option values for the SNMP trap event handler are set in your kapacitor.conf. Below is an example configuration:

[snmptrap]
  enabled = true
  addr = "localhost:162"
  community = "kapacitor"
  retries = 1

enabled

Set to true to enable the SNMP trap event handler.

addr

The host:port address of the SNMP trap server.

community

The community to use for traps.

retries

Number of retries when sending traps.

Options

The following SNMP trap event handler options can be set in a handler file or when using .snmpTrap() in a TICKscript.

Name Type Description
trap-oid string OID of the trap.
data-list object Each data object has oid, type, and value fields. Each field is a string.

SNMP Trap Data Types

The SNMP trap event handler supports the following data types:

Abbreviation Datatype
c Counter
i Integer
n Null
s String
t Time ticks

Example: handler file

id: handler-id
topic: topic-name
kind: snmptrap
options:
  trap-oid: 1.3.6.1.4.1.1
  data-list:
    - oid: 1.3.6.1.4.1.1.5
      type: s
      value: '{{ .Level }}'
    - oid: 1.3.6.1.4.1.1.6
      type: i
      value: 50
    - oid: 1.3.6.1.4.1.1.7
      type: c
      value: '{{ index .Fields "num_requests" }}'
    - oid: 1.3.6.1.4.1.1.8
      type: s
      value: '{{ .Message }}'

Example: TICKscript

|alert()
  // ...
  .snmpTrap('1.3.6.1.4.1.1')
    .data('1.3.6.1.4.1.1.5', 's', '{{ .Level }}')
    .data('1.3.6.1.4.1.1.6', 'i', '50')
    .data('1.3.6.1.4.1.1.7', 'c', '{{ index .Fields "num_requests" }}')
    .data('1.3.6.1.4.1.1.8', 's', '{{ .Message }}')

Using the SNMP trap event handler

The SNMP trap event handler can be used in both TICKscripts and handler files to send alerts as SNMP traps.

Sending SNMP traps from a TICKscript

The following TICKscript uses the .snmptrap() event handler to send alerts as SNMP traps whenever idle CPU usage drops below 10%.

snmptrap-cpu-alert.tick

stream
  |from()
    .measurement('cpu')
  |alert()
    .crit(lambda: "usage_idle" < 10)
    .message('Hey, check your CPU')
    .snmpTrap('1.3.6.1.2.1.1')
      .data('1.3.6.1.2.1.1.7', 'i', '{{ index .Field "value" }}')

Publish to multiple topics from a defined handler

The following setup sends an alert to the cpu topic with the message, “Hey, check your CPU”. An SNMP trap handler is added that subscribes to the cpu topic and sends new alerts as SNMP traps.

Create a TICKscript that publishes alert messages to a topic. The TICKscript below sends an alert message to the cpu topic any time idle CPU usage drops below 10%.

cpu_alert.tick

stream
  |from()
    .measurement('cpu')
  |alert()
    .crit(lambda: "usage_idle" < 10)
    .message('Hey, check your CPU')
    .topic('cpu')

Add and enable the TICKscript:

kapacitor define cpu_alert -tick cpu_alert.tick
kapacitor enable cpu_alert

Create a handler file that subscribes to the cpu topic and uses the SNMP trap event handler to send alerts as SNMP traps.

snmptrap_cpu_handler.yaml

id: snmptrap-cpu-alert
topic: cpu
kind: snmptrap
options:
  trap-oid: '1.3.6.1.2.1.1'
  data-list:
    - oid: '1.3.6.1.2.1.1.7'
      type: i
      value: '{{ index .Field "value" }}'

Add the handler:

kapacitor define-topic-handler snmptrap_cpu_handler.yaml

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