> ## Documentation Index
> Fetch the complete documentation index at: https://docs.honeycomb.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Send Data from Instrumented Code to Collectors

> Configure your OpenTelemetry-instrumented applications to export telemetry to the Collectors running in your Kubernetes cluster.

If you're already using OpenTelemetry, or you've decided to instrument your code with OpenTelemetry's SDKs, you need to tell the SDKs where to send the telemetry data.

## Before You Begin

Before beginning this guide, you should have:

* Created a running Kubernetes cluster.
* Deployed some applications to your cluster and instrumented them with OpenTelemetry.
* [Deployed an OpenTelemetry Collector in DaemonSet mode, listening on the Node IP](/send-data/kubernetes/opentelemetry/create-telemetry-pipeline/#step-4-deploy-collectors).

## Forward Data from Your Application Code to the Collectors

Now that you have a telemetry pipeline in your cluster, you must configure the SDKs to forward the telemetry data to your Collectors.
To do this, you will use the [Kubernetes Downward API](https://kubernetes.io/docs/concepts/workloads/pods/downward-api/), which allows you to pass information about the wider context of your Kubernetes environment into your deployments and therefore your pods.
For example, you can use the Downward API to add environment variables that can store pieces of metadata, like the Cluster name.

In our Kubernetes Quick Start, you deployed a DaemonSet-mode Collector listening on the IP address of the node, which is where your SDK must send telemetry data.

1. Using the Downward API, create an environment variable and pass in the node's IP address:

   ```yaml theme={}
     env:
     - name: NODE_IP
       valueFrom:
         fieldRef:
           fieldPath: status.hostIP
   ```

2. Configure the node's environment variable name and value. In this example, we use .NET's standard environment variable, which is named `OTEL_EXPORTER_OTLP_ENDPOINT`, and set it to the value of the node's IP address.

   ```yaml theme={}
     env:
     - name: NODE_IP
       valueFrom:
         fieldRef:
           fieldPath: status.hostIP
     - name: OTEL_EXPORTER_OTLP_ENDPOINT
       value: http://$(NODE_IP):4317 
   ```

   <Note>
     For a list of OTLP exporter configuration options, visit [OpenTelemetry's Protocol Exporter](https://opentelemetry.io/docs/specs/otel/protocol/exporter/).
   </Note>

After a few minutes, data should start flowing through your observability pipeline and into Honeycomb.