#SDK Variables

OpenTelemetry SDK behavior is controlled through environment variables that configure various aspects of telemetry collection, processing, and export. The Instrumentation custom resource allows you to set these variables to customize how your instrumented applications generate and send telemetry data.

#Common SDK Environment Variables

The following environment variables are commonly used to configure OpenTelemetry SDK behavior:

#Service Identification

• OTEL_SERVICE_NAME - Defines the logical name of the service
• OTEL_RESOURCE_ATTRIBUTES - Specifies additional resource attributes as key-value pairs

#Exporter Configuration

• OTEL_TRACES_EXPORTER - Configures the trace exporter (e.g., otlp, jaeger, zipkin)
• OTEL_METRICS_EXPORTER - Configures the metrics exporter (e.g., otlp, prometheus)
• OTEL_LOGS_EXPORTER - Configures the logs exporter (e.g., otlp)

#OTLP Endpoint Configuration

• OTEL_EXPORTER_OTLP_ENDPOINT - Sets the OTLP endpoint for all signals
• OTEL_EXPORTER_OTLP_TRACES_ENDPOINT - Sets the OTLP endpoint specifically for traces
• OTEL_EXPORTER_OTLP_METRICS_ENDPOINT - Sets the OTLP endpoint specifically for metrics
• OTEL_EXPORTER_OTLP_LOGS_ENDPOINT - Sets the OTLP endpoint specifically for logs

#Protocol Configuration

• OTEL_EXPORTER_OTLP_PROTOCOL - Specifies the OTLP protocol (grpc or http/protobuf)
• OTEL_EXPORTER_OTLP_TRACES_PROTOCOL - Protocol for traces
• OTEL_EXPORTER_OTLP_METRICS_PROTOCOL - Protocol for metrics

#Configuring SDK Variables in Instrumentation CR

You can set SDK environment variables in the Instrumentation custom resource:

apiVersion: opentelemetry.io/v1alpha1
kind: Instrumentation
metadata:
  name: my-instrumentation
spec:
  env:
    - name: OTEL_RESOURCE_ATTRIBUTES
      value: deployment.environment.name=production
    - name: OTEL_TRACES_EXPORTER
      value: otlp
    - name: OTEL_METRICS_EXPORTER
      value: otlp
    - name: OTEL_EXPORTER_OTLP_ENDPOINT
      value: http://otel-collector:4318
    - name: OTEL_EXPORTER_OTLP_PROTOCOL
      value: http/protobuf

These variables are automatically injected into instrumented application containers.

#Sampling Configuration

Control trace sampling behavior with these variables:

• OTEL_TRACES_SAMPLER - Sampling strategy (e.g., always_on, always_off, traceidratio, parentbased_always_on)
• OTEL_TRACES_SAMPLER_ARG - Argument for the sampler (e.g., sampling ratio for traceidratio)

Example configuration:

spec:
  env:
    - name: OTEL_TRACES_SAMPLER
      value: parentbased_traceidratio
    - name: OTEL_TRACES_SAMPLER_ARG
      value: "0.1"

This configuration samples 10% of traces while respecting parent span sampling decisions.

#Propagation Configuration

Configure context propagation formats:

• OTEL_PROPAGATORS - Comma-separated list of propagators (e.g., tracecontext,baggage,b3)

Example:

spec:
  env:
    - name: OTEL_PROPAGATORS
      value: tracecontext,baggage

#Batch Processing Configuration

Control how telemetry data is batched before export:

• OTEL_BSP_SCHEDULE_DELAY - Delay interval between batch exports (milliseconds)
• OTEL_BSP_EXPORT_TIMEOUT - Maximum time to wait for export (milliseconds)
• OTEL_BSP_MAX_QUEUE_SIZE - Maximum queue size for batching
• OTEL_BSP_MAX_EXPORT_BATCH_SIZE - Maximum batch size for export

#Logging Configuration

Configure SDK logging behavior:

• OTEL_LOG_LEVEL - SDK log level (e.g., debug, info, warn, error)

#Variable Precedence

When the same variable is defined in multiple places, the following precedence order applies (highest to lowest):

1. Environment variables defined directly in the pod specification
2. Environment variables from the Instrumentation CR
3. Default values from the instrumentation library