Environment variables

Environment variables for the Collector.

The Splunk Distribution of the OpenTelemetry Collector uses both upstream and Splunk-specific environment variables.

Upstream environment variables

Upstream environment variables are common to all OpenTelemetry implementations, such as OTEL_RESOURCE_ATTRIBUTES or OTEL_SERVICE_NAME.

For a detailed list of the upstream environment variables, refer to OpenTelemetry official docs. See more at Environment variable specification .

Splunk-specific environment variables

Note: You can use the legacy or new API and service endpoint URLs as of March 24, 2026. The legacy endpoints have the domain signalfx, and the new endpoints have the domain observability.splunkcloud. Thus, you can use the legacy ingest endpoint ingest.realm.signalfx.com or the new ingest endpoint ingest.realm.observability.splunkcloud.com. See Splunk Observability Cloud domain change for more information.
Splunk-specific environment variables are listed on the table below:

Name

Description

Default config?

SPLUNK_ACCESS_TOKEN

The Splunk access token to authenticate requests.

Yes

SPLUNK_API_URL

The Splunk API URL. For example, https://api.us0.observability.splunkcloud.com.

Yes

SPLUNK_BALLAST_SIZE_MIB (deprecated)

memory_ballast is deprecated. If you’re using this variable, see how to update your configuration.

No

SPLUNK_BUNDLE_DIR

The path to the Smart Agent bundle. For example, /usr/lib/splunk-otel-collector/agent-bundle.

Yes

SPLUNK_COLLECTD_DIR

The path to the collectd config directory for the Smart Agent. For example, /usr/lib/splunk-otel-collector/agent-bundle/run/collectd.

Yes

SPLUNK_CONFIG

Destination path of the Collector custom configuration file.

No

SPLUNK_CONFIG_YAML

Specifies your custom configuration YAML. This is useful in environments where access to the underlying file system is not readily available.

No

SPLUNK_DEBUG_CONFIG_SERVER (deprecated)

By default, the Collector provides a sensitive value-redacting, local config server listening at http://localhost:55554/debug/configz/effective, which is helpful in troubleshooting. To deactivate it, set SPLUNK_DEBUG_CONFIG_SERVER to any value other than true. To set the desired port to listen to, use SPLUNK_DEBUG_CONFIG_SERVER_PORT.

No

SPLUNK_HEC_TOKEN

The Splunk HEC authentication token.

Yes

SPLUNK_HEC_URL

The Splunk HEC endpoint URL. For example, https://ingest.us0.observability.splunkcloud.com/v1/log.

Yes

SPLUNK_INGEST_URL

The Splunk ingest URL. For example, https://ingest.us0.observability.splunkcloud.com.

Yes

SPLUNK_LISTEN_INTERFACE

The network interface the agent receivers listen on. 0.0.0.0 by default.

Yes

SPLUNK_MEMORY_LIMIT_MIB

Use it to set the memory limit for the memory_limiter processor. 512 MiB by default.

No

SPLUNK_MEMORY_TOTAL_MIB

Total memory in MiB to allocate to the Collector. SPLUNK_MEMORY_TOTAL_MIB sets GOMEMLIMIT of the Collector, although an explicit GOMEMLIMIT setting takes precedence.

No

SPLUNK_REALM

Your Splunk realm.

No

SPLUNK_TRACE_URL

The Splunk trace endpoint URL. For example, https://ingest.us0.observability.splunkcloud.com/v2/trace.

Yes

SPLUNK_*_URL environment variables are automatically derived from SPLUNK_REALM. For example, SPLUNK_INGEST_URL = https://ingest.SPLUNK_REALM.observability.splunkcloud.com.