Kapacitor can be integrated into a monitoring system by sending alert messages to supported event handlers. Currently, Kapacitor can send alert messages to specific log files and specific URLs, as well as to many third party applications.
Note: Setup instructions are not currently available for all supported event handlers, but additional information will be added over time. If you are familiar with the setup process for a specific event handler, please feel free to contribute.
Configuring Event Handlers
Required and default configuration options for most event handlers are
configured in your Kapacitor configuration file,
The default location for this is
/etc/kapacitor/kapacitor.conf, but may be
different depending on your Kapacitor setup.
Many event handlers provide options that can be defined in a TICKscript or in a handler file while some can only be configured in a handler file. These configurable options are outlined in the documentation for each handler.
Adding and using event handlers
If necessary, enable the desired event handler in your
enabled, you can create use the handler in two different ways.
- Create a topic handler with a handler file.
Note: Not all event handlers can be used in TICKscripts.
An event handler file is a simple YAML or JSON file that contains information about the handler. Though many handlers can be added in a TICKscript, this can become combersome when managing multiple handlers. Handler files allow you to add and use handlers outside of TICKscripts. For some handler types, using handler files is the only option.
The handler file contains the following:
- ID*: The unique ID of the handler.
- Topic*: The topic to which the handler subscribes.
- Match: A lambda expression to filter matching alerts. By default all alerts match. Learn more about match expressions.
- Kind*: The kind of handler.
- Options: Configurable options determined by the handler kind. If none are
provided, default values defined for the handler in the
kapacitor.confwill be used.
id: handler-id topic: topic-name match: changed() kind: slack options: channel: '#oh-nos'
Add the handler
Use the Kapacitor CLI to define a new handler with a handler file:
# Pattern kapacitor define-topic-handler <handler-file-name> # Example kapacitor define-topic-handler slack_cpu_handler.yaml
Many event handlers can be used directly in TICKscripts to send events.
This is generally done with handlers that send messages to third-parties. Below
is an example TICKscript that publishes CPU alerts to Slack using the
stream |from() .measurement('cpu') |alert() .crit(lambda: "idle_usage" < 10) .message('You better check your CPU usage.') .slack()
Events are sent to handlers if the alert is in a state other than ‘OK’ or the alert just changed to the ‘OK’ state from a non ‘OK’ state (a.k.a. the alert recovered). Using the AlertNode.StateChangesOnly property events will only be sent to handlers if the alert changed state.