Configuration

You can configure the OpenTelemetry Collector to suit your observability needs. Before you learn how Collector configuration works, familiarize yourself with the following content:

• Data collection concepts, to understand the repositories applicable to the OpenTelemetry Collector.
• Security guidance for end users
• Security guidance for component developers

Location

By default, the Collector configuration is located in /etc/<otel-directory>/config.yaml, where <otel-directory> can be otelcol, otelcol-contrib, or another value, depending on the Collector version or the Collector distribution you’re using.

You can provide one or more configurations using the --config option. For example:

otelcol --config=customconfig.yaml

You can also provide configurations using environment variables, HTTP URIs, or YAML paths. For example:

otelcol --config=env:MY_CONFIG_IN_AN_ENVVAR --config=https://server/config.yaml
otelcol --config="yaml:exporters::debug::verbosity: normal"

To validate a configuration file, use the validate command. For example:

otelcol validate --config=customconfig.yaml

Configuration structure

The structure of any Collector configuration file consists of four classes of pipeline components that access telemetry data:

• Receivers
• Processors
• Exporters
• Connectors

After each pipeline component is configured you must enable it using the pipelines within the service section of the configuration file.

Besides pipeline components you can also configure extensions, which provide capabilities that can be added to the Collector, such as diagnostic tools. Extensions don’t require direct access to telemetry data and are enabled through the service section.

The following is an example of Collector configuration with a receiver, a processor, an exporter, and three extensions.

receivers:
  otlp:
    protocols:
      grpc:
        endpoint: 0.0.0.0:4317
      http:
        endpoint: 0.0.0.0:4318
processors:
  batch:

exporters:
  otlp:
    endpoint: otelcol:4317

extensions:
  health_check:
  pprof:
  zpages:

service:
  extensions: [health_check, pprof, zpages]
  pipelines:
    traces:
      receivers: [otlp]
      processors: [batch]
      exporters: [otlp]
    metrics:
      receivers: [otlp]
      processors: [batch]
      exporters: [otlp]
    logs:
      receivers: [otlp]
      processors: [batch]
      exporters: [otlp]

Note that receivers, processors, exporters and pipelines are defined through component identifiers following the type[/name] format, for example otlp or otlp/2. You can define components of a given type more than once as long as the identifiers are unique. For example:

receivers:
  otlp:
    protocols:
      grpc:
        endpoint: 0.0.0.0:4317
      http:
        endpoint: 0.0.0.0:4318
  otlp/2:
    protocols:
      grpc:
        endpoint: 0.0.0.0:55690

processors:
  batch:
  batch/test:

exporters:
  otlp:
    endpoint: otelcol:4317
  otlp/2:
    endpoint: otelcol2:4317

extensions:
  health_check:
  pprof:
  zpages:

service:
  extensions: [health_check, pprof, zpages]
  pipelines:
    traces:
      receivers: [otlp]
      processors: [batch]
      exporters: [otlp]
    traces/2:
      receivers: [otlp/2]
      processors: [batch/test]
      exporters: [otlp/2]
    metrics:
      receivers: [otlp]
      processors: [batch]
      exporters: [otlp]
    logs:
      receivers: [otlp]
      processors: [batch]
      exporters: [otlp]

The configuration can also include other files, causing the Collector to merge them in a single in-memory representation of the YAML configuration:

receivers:
  otlp:
    protocols:
      grpc:
        endpoint: 0.0.0.0:4317

exporters: ${file:exporters.yaml}

service:
  extensions: []
  pipelines:
    traces:
      receivers: [otlp]
      processors: []
      exporters: [otlp]

With the exporters.yaml file being:

otlp:
  endpoint: otelcol.observability.svc.cluster.local:443

The final result in memory will be:

receivers:
  otlp:
    protocols:
      grpc:
        endpoint: 0.0.0.0:4317

exporters:
  otlp:
    endpoint: otelcol.observability.svc.cluster.local:443

service:
  extensions: []
  pipelines:
    traces:
      receivers: [otlp]
      processors: []
      exporters: [otlp]

Receivers

Receivers collect telemetry from one or more sources. They can be pull or push based, and may support one or more data sources.

Receivers are configured in the receivers section. Many receivers come with default settings, so that specifying the name of the receiver is enough to configure it. If you need to configure a receiver or want to change the default configuration, you can do so in this section. Any setting you specify overrides the default values, if present.

Configuring a receiver does not enable it. Receivers are enabled by adding them to the appropriate pipelines within the service section.

The Collector requires one or more receivers. The following example shows various receivers in the same configuration file:

receivers:
  # Data sources: logs
  fluentforward:
    endpoint: 0.0.0.0:8006

  # Data sources: metrics
  hostmetrics:
    scrapers:
      cpu:
      disk:
      filesystem:
      load:
      memory:
      network:
      process:
      processes:
      paging:

  # Data sources: traces
  jaeger:
    protocols:
      grpc:
        endpoint: 0.0.0.0:4317
      thrift_binary:
      thrift_compact:
      thrift_http:

  # Data sources: traces, metrics, logs
  kafka:
    protocol_version: 2.0.0

  # Data sources: traces, metrics
  opencensus:

  # Data sources: traces, metrics, logs
  otlp:
    protocols:
      grpc:
        endpoint: 0.0.0.0:4317
      http:
        endpoint: 0.0.0.0:4318

  # Data sources: metrics
  prometheus:
    config:
      scrape_configs:
        - job_name: otel-collector
          scrape_interval: 5s
          static_configs:
            - targets: [localhost:8888]

  # Data sources: traces
  zipkin:

For detailed receiver configuration, see the receiver README.

Processors

Processors take the data collected by receivers and modify or transform it before sending it to the exporters. Data processing happens according to rules or settings defined for each processor, which might include filtering, dropping, renaming, or recalculating telemetry, among other operations. The order of the processors in a pipeline determines the order of the processing operations that the Collector applies to the signal.

Processors are optional, although some are recommended.

You can configure processors using the processors section of the Collector configuration file. Any setting you specify overrides the default values, if present.

Configuring a processor does not enable it. Processors are enabled by adding them to the appropriate pipelines within the service section.

The following example shows several default processors in the same configuration file. You can find the full list of processors by combining the list from opentelemetry-collector-contrib and the list from opentelemetry-collector.

processors:
  # Data sources: traces
  attributes:
    actions:
      - key: environment
        value: production
        action: insert
      - key: db.statement
        action: delete
      - key: email
        action: hash

  # Data sources: traces, metrics, logs
  batch:

  # Data sources: metrics
  filter:
    metrics:
      include:
        match_type: regexp
        metric_names:
          - prefix/.*
          - prefix_.*

  # Data sources: traces, metrics, logs
  memory_limiter:
    check_interval: 5s
    limit_mib: 4000
    spike_limit_mib: 500

  # Data sources: traces
  resource:
    attributes:
      - key: cloud.zone
        value: zone-1
        action: upsert
      - key: k8s.cluster.name
        from_attribute: k8s-cluster
        action: insert
      - key: redundant-attribute
        action: delete

  # Data sources: traces
  probabilistic_sampler:
    hash_seed: 22
    sampling_percentage: 15

  # Data sources: traces
  span:
    name:
      to_attributes:
        rules:
          - ^\/api\/v1\/document\/(?P<documentId>.*)\/update$
      from_attributes: [db.svc, operation]
      separator: '::'

For detailed processor configuration, see the processor README.

Exporters

Exporters send data to one or more backends or destinations. Exporters can be pull or push based, and may support one or more data sources.

The exporters section contains exporters configuration. Most exporters require configuration to specify at least the destination, as well as security settings, like authentication tokens or TLS certificates. Any setting you specify overrides the default values, if present.

Configuring an exporter does not enable it. Exporters are enabled by adding them to the appropriate pipelines within the service section.

The Collector requires one or more exporters. The following example shows various exporters in the same configuration file:

exporters:
  # Data sources: traces, metrics, logs
  file:
    path: ./filename.json

  # Data sources: traces
  otlp/jaeger:
    endpoint: jaeger-server:4317
    tls:
      cert_file: cert.pem
      key_file: cert-key.pem

  # Data sources: traces, metrics, logs
  kafka:
    protocol_version: 2.0.0

  # Data sources: traces, metrics, logs
  # NOTE: Prior to v0.86.0 use `logging` instead of `debug`
  debug:
    verbosity: detailed

  # Data sources: traces, metrics
  opencensus:
    endpoint: otelcol2:55678

  # Data sources: traces, metrics, logs
  otlp:
    endpoint: otelcol2:4317
    tls:
      cert_file: cert.pem
      key_file: cert-key.pem

  # Data sources: traces, metrics
  otlphttp:
    endpoint: https://otlp.example.com:4318

  # Data sources: metrics
  prometheus:
    endpoint: 0.0.0.0:8889
    namespace: default

  # Data sources: metrics
  prometheusremotewrite:
    endpoint: http://prometheus.example.com:9411/api/prom/push
    # When using the official Prometheus (running via Docker)
    # endpoint: 'http://prometheus:9090/api/v1/write', add:
    # tls:
    #   insecure: true

  # Data sources: traces
  zipkin:
    endpoint: http://zipkin.example.com:9411/api/v2/spans

Notice that some exporters require x.509 certificates in order to establish secure connections, as described in setting up certificates.

For more information on exporter configuration, see the exporter README.md.

Connectors

Connectors join two pipelines, acting as both exporter and receiver. A connector consumes data as an exporter at the end of one pipeline and emits data as a receiver at the beginning of another pipeline. The data consumed and emitted may be of the same type or of different data types. You can use connectors to summarize consumed data, replicate it, or route it.

You can configure one or more connectors using the connectors section of the Collector configuration file. By default, no connectors are configured. Each type of connector is designed to work with one or more pairs of data types and may only be used to connect pipelines accordingly.

Configuring a connector doesn’t enable it. Connectors are enabled through pipelines within the service section.

The following example shows the count connector and how it’s configured in the pipelines section. Notice that the connector acts as an exporter for traces and as a receiver for metrics, connecting both pipelines:

receivers:
  foo:

exporters:
  bar:

connectors:
  count:
    spanevents:
      my.prod.event.count:
        description: The number of span events from my prod environment.
        conditions:
          - 'attributes["env"] == "prod"'
          - 'name == "prodevent"'

service:
  pipelines:
    traces:
      receivers: [foo]
      exporters: [count]
    metrics:
      receivers: [count]
      exporters: [bar]

For detailed connector configuration, see the connector README.

Extensions

Extensions are optional components that expand the capabilities of the Collector to accomplish tasks not directly involved with processing telemetry data. For example, you can add extensions for Collector health monitoring, service discovery, or data forwarding, among others.

You can configure extensions through the extensions section of the Collector configuration file. Most extensions come with default settings, so you can configure them just by specifying the name of the extension. Any setting you specify overrides the default values, if present.

Configuring an extension doesn’t enable it. Extensions are enabled within the service section.

By default, no extensions are configured. The following example shows several extensions configured in the same file:

extensions:
  health_check:
  pprof:
  zpages:

For detailed extension configuration, see the extension README.

Service section

The service section is used to configure what components are enabled in the Collector based on the configuration found in the receivers, processors, exporters, and extensions sections. If a component is configured, but not defined within the service section, then it’s not enabled.

The service section consists of three subsections:

• Extensions
• Pipelines
• Telemetry

Extensions

The extensions subsection consists of a list of desired extensions to be enabled. For example:

service:
  extensions: [health_check, pprof, zpages]

Pipelines

The pipelines subsection is where the pipelines are configured, which can be of the following types:

• traces collect and processes trace data.
• metrics collect and processes metric data.
• logs collect and processes log data.

A pipeline consists of a set of receivers, processors and exporters. Before including a receiver, processor, or exporter in a pipeline, make sure to define its configuration in the appropriate section.

You can use the same receiver, processor, or exporter in more than one pipeline. When a processor is referenced in multiple pipelines, each pipeline gets a separate instance of the processor.

The following is an example of pipeline configuration. Note that the order of processors dictates the order in which data is processed:

service:
  pipelines:
    metrics:
      receivers: [opencensus, prometheus]
      processors: [batch]
      exporters: [opencensus, prometheus]
    traces:
      receivers: [opencensus, jaeger]
      processors: [batch, memory_limiter]
      exporters: [opencensus, zipkin]

Telemetry

The telemetry config section is where you can set up observability for the Collector itself. It consists of two subsections: logs and metrics. To learn how to configure these signals, see Activate internal telemetry in the Collector.

Other Information

Environment variables

The use and expansion of environment variables is supported in the Collector configuration. For example to use the values stored on the DB_KEY and OPERATION environment variables you can write the following:

processors:
  attributes/example:
    actions:
      - key: ${env:DB_KEY}
        action: ${env:OPERATION}

Use $$ to indicate a literal $. For example, representing $DataVisualization would look like the following:

exporters:
  prometheus:
    endpoint: prometheus:8889
    namespace: $$DataVisualization

Proxy support

Exporters that use the net/http package respect the following proxy environment variables:

• HTTP_PROXY: Address of the HTTP proxy
• HTTPS_PROXY: Address of the HTTPS proxy
• NO_PROXY: Addresses that must not use the proxy

If set at Collector start time, exporters, regardless of the protocol, proxy traffic or bypass proxy traffic as defined by these environment variables.

Authentication

Most receivers exposing an HTTP or gRPC port can be protected using the Collector’s authentication mechanism. Similarly, most exporters using HTTP or gRPC clients can add authentication to outgoing requests.

The authentication mechanism in the Collector uses the extensions mechanism, allowing for custom authenticators to be plugged into Collector distributions. Each authentication extension has two possible usages:

• As client authenticator for exporters, adding auth data to outgoing requests
• As server authenticator for receivers, authenticating incoming connections.

For a list of known authenticators, see the Registry. If you’re interested in developing a custom authenticator, see Building an authenticator extension.

To add a server authenticator to a receiver in the Collector, follow these steps:

1. Add the authenticator extension and its configuration under .extensions.
2. Add a reference to the authenticator to .services.extensions, so that it’s loaded by the Collector.
3. Add a reference to the authenticator under .receivers.<your-receiver>.<http-or-grpc-config>.auth.

The following example uses the OIDC authenticator on the receiver side, making this suitable for a remote Collector that receives data from an OpenTelemetry Collector acting as agent:

extensions:
  oidc:
    issuer_url: http://localhost:8080/auth/realms/opentelemetry
    audience: collector

receivers:
  otlp/auth:
    protocols:
      grpc:
        endpoint: 0.0.0.0:4317
        auth:
          authenticator: oidc

processors:

exporters:
  # NOTE: Prior to v0.86.0 use `logging` instead of `debug`.
  debug:

service:
  extensions:
    - oidc
  pipelines:
    traces:
      receivers:
        - otlp/auth
      processors: []
      exporters:
        - debug

On the agent side, this is an example that makes the OTLP exporter obtain OIDC tokens, adding them to every RPC made to a remote Collector:

extensions:
  oauth2client:
    client_id: agent
    client_secret: some-secret
    token_url: http://localhost:8080/auth/realms/opentelemetry/protocol/openid-connect/token

receivers:
  otlp:
    protocols:
      grpc:
        endpoint: 0.0.0.0:4317

processors:

exporters:
  otlp/auth:
    endpoint: remote-collector:4317
    auth:
      authenticator: oauth2client

service:
  extensions:
    - oauth2client
  pipelines:
    traces:
      receivers:
        - otlp
      processors: []
      exporters:
        - otlp/auth

Configuring certificates

In a production environment, use TLS certificates for secure communication or mTLS for mutual authentication. Follow these steps to generate self-signed certificates as in this example. You might want to use your current cert provisioning procedures to procure a certificate for production usage.

Install cfssl and create the following csr.json file:

{
  "hosts": ["localhost", "127.0.0.1"],
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "O": "OpenTelemetry Example"
    }
  ]
}

Then run the following commands:

cfssl genkey -initca csr.json | cfssljson -bare ca
cfssl gencert -ca ca.pem -ca-key ca-key.pem csr.json | cfssljson -bare cert

This creates two certificates:

• An “OpenTelemetry Example” Certificate Authority (CA) in ca.pem, with the associated key in ca-key.pem
• A client certificate in cert.pem, signed by the OpenTelemetry Example CA, with the associated key in cert-key.pem.

Override settings

You can override Collector settings using the --set option. The settings you define with this method are merged into the final configuration after all --config sources are resolved and merged.

The following examples show how to override settings inside nested sections:

otelcol --set "exporters::debug::verbosity=detailed"
otelcol --set "receivers::otlp::protocols::grpc={endpoint:localhost:4317, compression: gzip}"