[[monitor-options]]
=== Common monitor options

You can specify the following options when defining a {beatname_uc} monitor in any location.
These options are the same for all monitors. Each monitor type has additional configuration
options that are specific to that monitor type.

[float]
[[monitor-type]]
==== `type`

The type of monitor to run. See <<monitor-types>>.

[float]
[[monitor-id]]
==== `id`

A unique identifier for this configuration. This should not change with edits to the monitor configuration
regardless of changes to any config fields. Examples: `uploader-service`, `http://example.net`, `us-west-loadbalancer`. Note that this uniqueness is only within a given beat instance. If you want to monitor the same endpoint from multiple locations it is recommended that those heartbeat instances use the same IDs so that their results can be correlated. You can use the `host.geo.name` property to disambiguate them.

When querying against indexed monitor data this is the field you will be aggregating with. Appears in the
<<exported-fields,exported fields>> as `monitor.id`.

If you do not set this explicitly the monitor's config will be hashed and a generated value used. This value will
change with any options change to this monitor making aggregations over time between changes impossible. For this reason
it is recommended that you set this manually.

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[[monitor-name]]
==== `name`

Optional human readable name for this monitor. This value appears in the <<exported-fields,exported fields>>
as `monitor.name`.


[float]
[[service-name]]
==== `service.name`

Optional APM service name for this monitor. Corresponds to the `service.name` ECS field. Set this when monitoring an app
that is also using APM to enable integrations between Uptime and APM data in Kibana.

[float]
[[monitor-enabled]]
==== `enabled`

A Boolean value that specifies whether the module is enabled. If the `enabled`
option is missing from the configuration block, the module is enabled by
default.

[float]
[[monitor-schedule]]
==== `schedule`

A cron-like expression that specifies the task schedule. For example:

* `*/5 * * * * * *` runs the task every 5 seconds (for example, at 10:00:00,
10:00:05, and so on).
* `@every 5s` runs the task every 5 seconds from the time when {beatname_uc} was
started.

The `schedule` option uses a cron-like syntax based on https://github.com/gorhill/cronexpr#implementation[this `cronexpr` implementation],
but adds the `@every` keyword.

For stats on the execution of scheduled tasks you can enable the HTTP stats server with `http.enabled: true` in heartbeat.yml, then run `curl http://localhost:5066/stats | jq .heartbeat.scheduler` to view the scheduler's stats. Stats are provided for both jobs and tasks. Each time a monitor is scheduled is considered to be a single job, while portions of the work a job does, like DNS lookups and executing network requests are defined as tasks. The stats provided are:

* **jobs.active:** The number of actively running jobs/monitors.
* **jobs.missed_deadline:** The number of jobs that executed after their scheduled time. This can be caused either by overlong long timeouts from the previous job or high load preventing heartbeat from keeping up with work.
* **tasks.active:** The number of tasks currently running.
* **tasks.waiting:** If the global `schedule.limit` option is set, this number will reflect the number of tasks that are ready to execute, but have not been started in order to prevent exceeding `schedule.limit`.

Also see the <<monitors-scheduler,task scheduler>> settings.

[float]
[[monitor-ipv4]]
==== `ipv4`

A Boolean value that specifies whether to ping using the ipv4 protocol if
hostnames are configured. The default is `true`.

[float]
[[monitor-ipv6]]
==== `ipv6`

A Boolean value that specifies whether to ping using the ipv6 protocol
if hostnames are configured. The default is `true`.

[float]
[[monitor-mode]]
==== `mode`

If `mode` is `any`, the monitor pings only one IP address for a hostname. If
`mode` is `all`, the monitor pings all resolvable IPs for a hostname. The
`mode: all` setting is useful if you are using a DNS-load balancer and want to
ping every IP address for the specified hostname. The default is `any`.

[float]
[[monitor-timeout]]
==== `timeout`

The total running time for each ping test. This is the total time allowed for
testing the connection and exchanging data. The default is 16 seconds (16s).

If the timeout is exceeded, {beatname_uc} publishes a `service-down` event. If the
value specified for `timeout` is greater than `schedule`, intermediate checks
will not be executed by the scheduler.

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[[monitor-fields]]
==== `fields`

Optional fields that you can specify to add additional information to the
output. For example, you might add fields that you can use for filtering log
data. Fields can be scalar values, arrays, dictionaries, or any nested
combination of these. By default, the fields that you specify here will be
grouped under a `fields` sub-dictionary in the output document. To store the
custom fields as top-level fields, set the `fields_under_root` option to true.
If a duplicate field is declared in the general configuration, then its value
will be overwritten by the value declared here.

[float]
[[monitor-fields-under-root]]
==== `fields_under_root`

If this option is set to true, the custom <<monitor-fields,fields>>
are stored as top-level fields in the output document instead of being grouped
under a `fields` sub-dictionary. If the custom field names conflict with other
field names added by {beatname_uc}, then the custom fields overwrite the other
fields.

[float]
[[monitor-tags]]
==== `tags`

A list of tags that will be sent with the monitor event. This setting is optional.

[float]
[[monitor-processors]]
==== `processors`

A list of processors to apply to the data generated by the monitor.

See <<filtering-and-enhancing-data>> for information about specifying
processors in your config.

[float]
[[monitor-pipeline]]
===== `pipeline`

The Ingest Node pipeline ID to set for the events generated by this input.

NOTE: The pipeline ID can also be configured in the Elasticsearch output, but
this option usually results in simpler configuration files. If the pipeline is
configured both in the input and output, the option from the
input is used.

[float]
[[monitor-index]]
===== `index`

If present, this formatted string overrides the index for events from this input
(for elasticsearch outputs), or sets the `raw_index` field of the event's
metadata (for other outputs). This string can only refer to the agent name and
version and the event timestamp; for access to dynamic fields, use
`output.elasticsearch.index` or a processor.

Example value: `"%{[agent.name]}-myindex-%{+yyyy.MM.dd}"` might
expand to `"heartbeat-myindex-2019.11.01"`.

[float]
[[monitor-keep-null]]
==== `keep_null`

If this option is set to true, fields with `null` values will be published in
the output document. By default, `keep_null` is set to `false`.
