What Is OpenTelemetry? Observability Standard Explained Simply

pip install opentelemetry-sdk \
            opentelemetry-instrumentation-fastapi \
            opentelemetry-exporter-otlp

# main.py
from opentelemetry import trace
from opentelemetry.sdk.trace import TracerProvider
from opentelemetry.sdk.trace.export import BatchSpanProcessor
from opentelemetry.exporter.otlp.proto.grpc.trace_exporter import OTLPSpanExporter
from opentelemetry.instrumentation.fastapi import FastAPIInstrumentor
from fastapi import FastAPI
 
# Set up tracing
provider = TracerProvider()
processor = BatchSpanProcessor(
    OTLPSpanExporter(endpoint="http://otel-collector:4317")
)
provider.add_span_processor(processor)
trace.set_tracer_provider(provider)
 
app = FastAPI()
FastAPIInstrumentor.instrument_app(app)  # Auto-instruments all routes
 
tracer = trace.get_tracer(__name__)
 
@app.get("/users/{user_id}")
def get_user(user_id: str):
    with tracer.start_as_current_span("get-user-from-db") as span:
        span.set_attribute("user.id", user_id)
        # ... your code
        return {"id": user_id}

# otel-collector-config.yaml
receivers:
  otlp:
    protocols:
      grpc:
        endpoint: 0.0.0.0:4317
      http:
        endpoint: 0.0.0.0:4318
 
processors:
  batch:
    timeout: 1s
  resource:
    attributes:
    - key: service.environment
      value: production
      action: insert
 
exporters:
  jaeger:
    endpoint: jaeger:14250
  prometheus:
    endpoint: "0.0.0.0:8889"
  loki:
    endpoint: http://loki:3100/loki/api/v1/push
 
service:
  pipelines:
    traces:
      receivers: [otlp]
      processors: [batch, resource]
      exporters: [jaeger]
    metrics:
      receivers: [otlp]
      processors: [batch]
      exporters: [prometheus]
    logs:
      receivers: [otlp]
      processors: [batch]
      exporters: [loki]

apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: otel-collector
  namespace: monitoring
spec:
  selector:
    matchLabels:
      app: otel-collector
  template:
    spec:
      containers:
      - name: collector
        image: otel/opentelemetry-collector-contrib:latest
        ports:
        - containerPort: 4317  # OTLP gRPC
        - containerPort: 4318  # OTLP HTTP
        volumeMounts:
        - name: config
          mountPath: /etc/otelcol
      volumes:
      - name: config
        configMap:
          name: otel-collector-config

# Install the operator
kubectl apply -f https://github.com/open-telemetry/opentelemetry-operator/releases/latest/download/opentelemetry-operator.yaml

# Annotate your deployment to enable auto-instrumentation
apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app
  annotations:
    instrumentation.opentelemetry.io/inject-python: "true"  # or java, nodejs, dotnet