OTEL OAuth2 Exporter Configuration

Configure the OpenTelemetry Collector to authenticate to backends using OAuth2 client credentials flow.

Table of Contents

• Overview
• Configuration Pattern
• Environment Variable Injection
• TLS Configuration
• Helm Chart Integration
• Troubleshooting

Overview

When exporting traces to backends that require authentication (e.g., MLflow with Keycloak), the OTEL Collector can use the oauth2clientauthextension to obtain and attach bearer tokens automatically.

Configuration Pattern

Extension Configuration

extensions:
  oauth2client/mlflow:
    client_id: ${env:MLFLOW_CLIENT_ID}
    client_secret: ${env:MLFLOW_CLIENT_SECRET}
    token_url: ${env:KEYCLOAK_TOKEN_URL}
    scopes: ["openid"]
    timeout: 10s
    tls:
      ca_file: /etc/pki/ca-trust/extracted/pem/tls-ca-bundle.pem

Exporter with Auth

exporters:
  otlphttp/mlflow:
    traces_endpoint: http://mlflow:5000/v1/traces
    auth:
      authenticator: oauth2client/mlflow

Full Pipeline Configuration

extensions:
  health_check: {}
  oauth2client/mlflow:
    client_id: ${env:MLFLOW_CLIENT_ID}
    client_secret: ${env:MLFLOW_CLIENT_SECRET}
    token_url: ${env:KEYCLOAK_TOKEN_URL}
    scopes: ["openid"]
    timeout: 10s
    tls:
      ca_file: /etc/pki/ca-trust/extracted/pem/tls-ca-bundle.pem

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

processors:
  batch:
    timeout: 1s
    send_batch_size: 100

exporters:
  otlphttp/mlflow:
    traces_endpoint: http://mlflow:5000/v1/traces
    auth:
      authenticator: oauth2client/mlflow

service:
  extensions: [health_check, oauth2client/mlflow]
  pipelines:
    traces:
      receivers: [otlp]
      processors: [batch]
      exporters: [otlphttp/mlflow]

Environment Variable Injection

From Kubernetes Secret

containers:
  - name: otel-collector
    env:
      - name: MLFLOW_CLIENT_ID
        valueFrom:
          secretKeyRef:
            name: mlflow-oauth-secret
            key: MLFLOW_CLIENT_ID
      - name: MLFLOW_CLIENT_SECRET
        valueFrom:
          secretKeyRef:
            name: mlflow-oauth-secret
            key: MLFLOW_CLIENT_SECRET
      - name: KEYCLOAK_TOKEN_URL
        value: "http://keycloak-service.keycloak.svc.cluster.local:8080/realms/master/protocol/openid-connect/token"

TLS Configuration

For External Token Endpoints

When the Keycloak endpoint uses HTTPS with a custom CA:

oauth2client/mlflow:
  tls:
    ca_file: /etc/pki/ca-trust/extracted/pem/tls-ca-bundle.pem
    insecure: false

For Internal Token Endpoints

When using the internal HTTP endpoint:

oauth2client/mlflow:
  token_url: http://keycloak-service.keycloak.svc.cluster.local:8080/realms/master/protocol/openid-connect/token
  # No TLS configuration needed

Helm Chart Integration

In charts/rossoctl-deps/templates/otel-collector.yaml:

{{- if .Values.otelCollector.mlflow.oauth2.enabled }}
extensions:
  oauth2client/mlflow:
    client_id: ${env:MLFLOW_CLIENT_ID}
    client_secret: ${env:MLFLOW_CLIENT_SECRET}
    token_url: {{ .Values.otelCollector.mlflow.oauth2.tokenUrl }}
    scopes: ["openid"]
    timeout: 10s
    {{- if .Values.otelCollector.mlflow.oauth2.tlsEnabled }}
    tls:
      ca_file: {{ .Values.otelCollector.mlflow.oauth2.caFile }}
    {{- end }}
{{- end }}

Troubleshooting

Token Request Fails

1. Check credentials:

kubectl exec -it otel-collector-xxx -n rossoctl-system -- env | grep MLFLOW

2. Test token endpoint manually:

curl -X POST "$KEYCLOAK_TOKEN_URL" \
  -d "grant_type=client_credentials" \
  -d "client_id=$MLFLOW_CLIENT_ID" \
  -d "client_secret=$MLFLOW_CLIENT_SECRET"

TLS Errors

1. Verify CA bundle is mounted:

kubectl exec -it otel-collector-xxx -n rossoctl-system -- \
  ls -la /etc/pki/ca-trust/extracted/pem/

2. Use internal Keycloak URL to avoid TLS:

http://keycloak-service.keycloak.svc.cluster.local:8080

Extension Not Loading

1. Ensure extension is listed in service.extensions
2. Check collector logs:

kubectl logs -n rossoctl-system -l app=otel-collector

Collector Image Requirements

The standard OTEL collector image includes oauth2clientauthextension. If using a custom build, ensure it's included:

# builder-config.yaml
extensions:
  - gomod: go.opentelemetry.io/collector/extension/auth/oauth2clientauthextension v0.x.x

Related Skills

• auth:keycloak-confidential-client
• openshift:trusted-ca-bundle
• genai:semantic-conventions - OTel GenAI semantic conventions for traces