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Tail-based sampling

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Tail-based sampling

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Tail-based sampling configuration options.

Example config file:

apm-server:
  host: "localhost:8200"
  rum:
    enabled: true

output:
  elasticsearch:
    hosts: ElasticsearchAddress:9200

max_procs: 4

Top-level tail-based sampling settings

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See Tail-based sampling to learn more.

Enable tail-based samplingedit

Set to true to enable tail based sampling. Disabled by default. (bool)

APM Server binary	`sampling.tail.enabled`
Fleet-managed	`Enable tail-based sampling`

Intervaledit

Synchronization interval for multiple APM Servers. Should be in the order of tens of seconds or low minutes. Default: 1m (1 minute). (duration)

APM Server binary	`sampling.tail.interval`
Fleet-managed	`Interval`

Policiesedit

Criteria used to match a root transaction to a sample rate.

Policies map trace events to a sample rate. Each policy must specify a sample rate. Trace events are matched to policies in the order specified. All policy conditions must be true for a trace event to match. Each policy list should conclude with a policy that only specifies a sample rate. This final policy is used to catch remaining trace events that don’t match a stricter policy. ([]policy)

APM Server binary	`sampling.tail.policies`
Fleet-managed	`Policies`

Storage limitedit

The amount of storage space allocated for trace events matching tail sampling policies. Caution: Setting this limit higher than the allowed space may cause APM Server to become unhealthy.

If the configured storage limit is insufficient, it logs "configured storage limit reached". The event will bypass sampling and will always be indexed when storage limit is reached.

Default: 3GB. (text)

APM Server binary	`sampling.tail.storage_limit`
Fleet-managed	`Storage limit`

Policy-level tail-based sampling settings

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See Tail-based sampling to learn more.

sample_rateedit

The sample rate to apply to trace events matching this policy. Required in each policy.

The sample rate must be greater than or equal to 0 and less than or equal to 1. For example, a sample_rate of 0.01 means that 1% of trace events matching the policy will be sampled. A sample_rate of 1 means that 100% of trace events matching the policy will be sampled. (int)

trace.nameedit

The trace name for events to match a policy. A match occurs when the configured trace.name matches the transaction.name of the root transaction of a trace. A root transaction is any transaction without a parent.id. (string)

trace.outcomeedit

The trace outcome for events to match a policy. A match occurs when the configured trace.outcome matches a trace’s event.outcome field. Trace outcome can be success, failure, or unknown. (string)

service.nameedit

The service name for events to match a policy. (string)

service.environmentedit

The service environment for events to match a policy. (string)

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