C
C#•3w ago
Denis

OpenTelemetry Metrics

I'm trying to configure an ASP.NET Core application to send metrics that I can then view via Grafana. I'm pretty confused about the whole observability architecture. Key points: - Everything is running within Docker Compose - I've managed to configure ASP -> OTLP -> Loki -> Grafana - I've managed to configure Prometheus to scrape OTLP metrics Potential issue: all examples I've seen magically connect to the OTLP collector without specifying its endpoint. Whenever I've tried that, didnt work, so I use HttpProtobuf mode with the HTTP endpoint injected from env. My confusion: I'm lost in the architecture. - Do I need OTLP? Why is it useful? - How does Prometheus come into play? Do I send metrics ASP -> OTLP and then configure Prom. to scrape that? Or expose my ASP metrics for Prom. to scrape and expose to Grafana? 
  prometheus:
    container_name: prometheus
    hostname: "prometheus"
    image: prom/prometheus:latest
    ports:
      - "9090:9090"
    volumes:
      - ./configs/prometheus.yml:/etc/prometheus/prometheus.yml
  collector:
    container_name: "collector"
    hostname: "collector"
    image: otel/opentelemetry-collector-contrib:latest
    command: '--config=/etc/otelcol/otel-collector-config.yml'
    volumes:
      - ./configs:/etc/otelcol
    ports:
      - "4317:4317"
      - "4318:4318"
      - "8888:8888"
      - "13133:13133"
      - "55679:55679"
      - "1777:1777"
      - "3500:3500"
      - "3600:3600"
  prometheus:
    container_name: prometheus
    hostname: "prometheus"
    image: prom/prometheus:latest
    ports:
      - "9090:9090"
    volumes:
      - ./configs/prometheus.yml:/etc/prometheus/prometheus.yml
  collector:
    container_name: "collector"
    hostname: "collector"
    image: otel/opentelemetry-collector-contrib:latest
    command: '--config=/etc/otelcol/otel-collector-config.yml'
    volumes:
      - ./configs:/etc/otelcol
    ports:
      - "4317:4317"
      - "4318:4318"
      - "8888:8888"
      - "13133:13133"
      - "55679:55679"
      - "1777:1777"
      - "3500:3500"
      - "3600:3600"
Excerpt from docker-compose.yml 
receivers:
  otlp:
    protocols:
      grpc:
        endpoint: 0.0.0.0:4317
      http:
        endpoint: 0.0.0.0:4318
  prometheus:
    config:
      scrape_configs:
        - job_name: 'collector'
          scrape_interval: 10s
          static_configs:
            - targets: ['0.0.0.0:8888']
exporters:
  otlphttp/metrics:
    endpoint: "http://prometheus:9090/api/v1/otlp"
service:
  pipelines:
    metrics:
      receivers: [otlp,prometheus]
      exporters: [debug,otlphttp/metrics]
receivers:
  otlp:
    protocols:
      grpc:
        endpoint: 0.0.0.0:4317
      http:
        endpoint: 0.0.0.0:4318
  prometheus:
    config:
      scrape_configs:
        - job_name: 'collector'
          scrape_interval: 10s
          static_configs:
            - targets: ['0.0.0.0:8888']
exporters:
  otlphttp/metrics:
    endpoint: "http://prometheus:9090/api/v1/otlp"
service:
  pipelines:
    metrics:
      receivers: [otlp,prometheus]
      exporters: [debug,otlphttp/metrics]
2 Replies
Denis
DenisOP•3w ago
My assumption is that OTLP Collector is a collector that takes logs, metrics and traces, to then distribute them to the desired exporters - loki, prometheus, whatever. But I cannot wrap my head around how to integrate Prometheus into the picture.
Joschi
Joschi•3w ago
Exactly! All apps can simply use the otlp exporter and send all their traces metrics and logs to the otel collector. Typically using the grpc endpoint. The otel collector can tze distribute all that data and also perform some transformations, like redaction and compression.

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