# OpenTelemetry Collector

> This document describes a sample setup for sending metrics to Last9 via OpenTelemetry Collector.

Source: https://last9.io/docs/integrations/observability/opentelemetry-collector/

## Prerequisites

1. Create a Last9 cluster by following [Getting Started](/docs/onboard/)
2. Keep the following information handy after creating the cluster:
   - `$levitate_remote_write_url`: Last9's Remote write endpoint
   - `$levitate_remote_write_username`: Cluster ID
   - `$levitate_remote_write_password`: Write token created for the cluster

## OpenTelemetry Collector Basics

![Information flow - Metrics to Last9 via OpenTelemetry](../../../../../../../assets/content/docs/integrations/observability/opentelemetry/opentelemetry-collector/1c188f8-image.png)

OpenTelemetry collectors consist of three parts:

1. Receivers
   - A receiver, which can be push or pull-based sends data to the collector
   - In this doc, we will use Prometheus receiver, as an example, which will receive metrics
2. Processors
   - Processors are run on data between being received and being exported
   - Processors are not mandatory for sending data to Last9
3. Exporters
   - An exporter, which can be push or pull-based, sends data to one or more
     backends/destinations
   - We will use Last9 as an exporter destination

## Setup

1. Create a `docker-compose.yaml` file with the following config:

   ```yaml
   version: "3.5"
   services:
     otel-collector:
       container_name: otel-collector-contrib
       image: otel/opentelemetry-collector-contrib:0.150.0
       command: ["--config=/etc/otelcol-config.yaml"]
       ports:
         - "8888:8888" # Prometheus metrics exposed by the collector
         - "13133:13133" # health_check extension
       volumes:
         - ./otel-config.yaml:/etc/otelcol-config.yaml
       restart: always
       networks:
         - monitoring
   networks:
     monitoring:
       driver: bridge
   ```

2. Create `otel-config.yaml` with a sample scrape config. Replace this scrape config by your desired config:

   ```
   extensions:
     basicauth/prw:
       client_auth:
         # Replace these variables by their actual values
         username: $levitate_remote_write_username
         password: $levitate_remote_write_password

   receivers:
     prometheus:
       config:
         scrape_configs:
         - job_name: 'otel-collector-01'
           scrape_interval: 60s
           static_configs:
           - targets: ['otel-collector:8888']

   exporters:
     prometheusremotewrite:
       auth:
         authenticator: basicauth/prw
       endpoint: "$levitate_remote_write_url" # Replace this variable by its actual value

   service:
     extensions: [basicauth/prw]
     pipelines:
       metrics:
         receivers: [prometheus]
         exporters: [prometheusremotewrite]
   ```

3. Deploy the setup using:

   ```
   docker-compose up
   ```

As per the config, the entire flow is combined in the `pipelines` section under the `service` where the data flows from OpenTelemetry Collector to Last9 using the basic auth mechanism.

:::note
The same config file `otel-config.yaml` can be used when using another compute layer e.g. K8s.
:::

---

## Troubleshooting

Please get in touch with us on [Discord](https://discord.com/invite/Q3p2EEucx9) or [Email](mailto:support@last9.io) if you have any questions.