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Alex Spinov
Alex Spinov

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Grafana Alloy Has a Free API — The OpenTelemetry Collector You Actually Want

#opentelemetry #grafana #observability #devops

TL;DR

Grafana Alloy is an open-source OpenTelemetry Collector distribution that replaces Grafana Agent. It collects metrics, logs, and traces with a programmable pipeline — and it's completely free.

What Is Grafana Alloy?

Grafana Alloy is Grafana's vendor-neutral telemetry collector:

  • OpenTelemetry native — built on OTel Collector components
  • Programmable pipelines — River configuration language (like HCL)
  • Metrics + Logs + Traces — all three signals in one binary
  • Grafana ecosystem — ships to Prometheus, Loki, Tempo, Mimir
  • Free and open source — Apache 2.0 license

Quick Start 

# Install on macOS
brew install grafana/grafana/alloy

# Install on Linux
curl -fsSL https://apt.grafana.com/gpg.key | sudo gpg --dearmor -o /etc/apt/keyrings/grafana.gpg
sudo apt-get install alloy

# Or Docker
docker run -v ./config.alloy:/etc/alloy/config.alloy \
  -p 12345:12345 grafana/alloy:latest \
  run /etc/alloy/config.alloy
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Configuration with River 

// config.alloy — Collect metrics from Prometheus endpoints

prometheus.scrape "default" {
  targets = [
    {"__address__" = "localhost:8080", "job" = "my-app"},
    {"__address__" = "localhost:9090", "job" = "prometheus"},
  ]
  forward_to = [prometheus.remote_write.grafana_cloud.receiver]
  scrape_interval = "15s"
}

prometheus.remote_write "grafana_cloud" {
  endpoint {
    url = "https://prometheus-prod.grafana.net/api/prom/push"
    basic_auth {
      username = env("GRAFANA_CLOUD_USER")
      password = env("GRAFANA_CLOUD_TOKEN")
    }
  }
}
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Collecting Logs 

// Tail log files and ship to Loki

local.file_match "app_logs" {
  path_targets = [{__path__ = "/var/log/app/*.log"}]
}

loki.source.file "logs" {
  targets    = local.file_match.app_logs.targets
  forward_to = [loki.write.grafana_cloud.receiver]
}

loki.write "grafana_cloud" {
  endpoint {
    url = "https://logs-prod.grafana.net/loki/api/v1/push"
    basic_auth {
      username = env("GRAFANA_CLOUD_USER")
      password = env("GRAFANA_CLOUD_TOKEN")
    }
  }
}
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OpenTelemetry Traces 

// Receive OTLP traces and forward to Tempo

otelcol.receiver.otlp "default" {
  grpc { endpoint = "0.0.0.0:4317" }
  http { endpoint = "0.0.0.0:4318" }
}

otelcol.exporter.otlp "tempo" {
  client {
    endpoint = "tempo-prod.grafana.net:443"
    auth     = otelcol.auth.basic.grafana_cloud.handler
  }
}

otelcol.auth.basic "grafana_cloud" {
  username = env("GRAFANA_CLOUD_USER")
  password = env("GRAFANA_CLOUD_TOKEN")
}

otelcol.receiver.otlp.default.output {
  traces = [otelcol.exporter.otlp.tempo.input]
}
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Alloy vs Other Collectors

Feature Alloy OTel Collector Datadog Agent Vector
Price Free Free Paid Free
Config language River (HCL) YAML YAML TOML
Metrics ✅ ✅ ✅ ✅
Logs ✅ ✅ ✅ ✅
Traces ✅ ✅ ✅ ❌
Programmable ✅ ❌ ❌ ✅
Live debugging UI ✅ :12345 ❌ ❌ ❌

Built-in Debug UI

Alloy ships with a debug UI at http://localhost:12345:

  • See pipeline graph visualization
  • Check component health
  • View live data flowing through
  • Debug configuration errors

Resources

Need to monitor your scraping infrastructure? My Apify tools extract web data at scale — pair with Grafana Alloy to monitor your data pipelines. Questions? Email spinov001@gmail.com

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