[Datadog collection] Update instructions for trace forwarding (#1911)

Co-authored-by: Clayton Cornell <131809008+clayton-cornell@users.noreply.github.com>
(cherry picked from commit 4d18fc4)

docs/sources/collect/datadog-traces-metrics.md

@@ -14,23 +14,23 @@ You can configure {{< param "PRODUCT_NAME" >}} to collect [Datadog][] traces and
 
 This topic describes how to:
 
-* Configure metrics and traces delivery.
+* Configure {{< param "PRODUCT_NAME" >}} to send traces and metrics.
 * Configure the {{< param "PRODUCT_NAME" >}} Datadog Receiver.
-* Configure the Datadog Agent to forward metrics to the {{< param "PRODUCT_NAME" >}} Datadog Receiver.
+* Configure the Datadog Agent to forward traces and metrics to the {{< param "PRODUCT_NAME" >}} Datadog Receiver.
 
 ## Before you begin
 
 * Ensure that at least one instance of the [Datadog Agent][] is collecting metrics and/or traces.
-* Identify where you will write collected metrics.
-  Metrics can be written to [Prometheus]() or any other OTel-compatible database such as Grafana Mimir, Grafana Cloud, or Grafana Enterprise Metrics.
+* Identify where you will write the collected telemetry.
+  Metrics can be written to [Prometheus]() or any other OpenTelemetry-compatible database such as Grafana Mimir, Grafana Cloud, or Grafana Enterprise Metrics.
   Traces can be written to Grafana Tempo, Grafana Cloud, or Grafana Enterprise Traces.
 * Be familiar with the concept of [Components][] in {{< param "PRODUCT_NAME" >}}.
 
-## Configure metrics delivery
+## Configure {{% param "PRODUCT_NAME" %}} to send traces and metrics
 
-Before components can collect Datadog metrics, you must have a component responsible for writing those metrics somewhere.
+Before components can collect Datadog telemetry signals, you must have a component responsible for writing this telemetry somewhere.
 
-The [otelcol.exporter.otlp][] component is responsible for delivering OTLP data to OTel-compatible endpoints.
+The [otelcol.exporter.otlp][] component is responsible for delivering OTLP data to OpenTelemetry-compatible endpoints.
 
 1. Add the following `otelcol.exporter.otlp` component to your configuration file.
 
@@ -45,7 +45,7 @@ The [otelcol.exporter.otlp][] component is responsible for delivering OTLP data
 
    Replace the following:
 
-    - _`<OTLP_ENDPOINT_URL>`_: The full URL of the OTel-compatible endpoint where metrics and traces will be sent, such as `https://otlp-gateway-prod-eu-west-2.grafana.net/otlp`.
+    - _`<OTLP_ENDPOINT_URL>`_: The full URL of the OpenTelemetry-compatible endpoint where metrics and traces will be sent, such as `https://otlp-gateway-prod-eu-west-2.grafana.net/otlp`.
 
 1. If your endpoint requires basic authentication, paste the following inside the `endpoint` block.
 
@@ -61,7 +61,7 @@ The [otelcol.exporter.otlp][] component is responsible for delivering OTLP data
     - _`<USERNAME>`_: The basic authentication username.
     - _`<PASSWORD>`_: The basic authentication password or API key.
 
-## Configure Datadog Receiver
+## Configure the {{% param "PRODUCT_NAME" %}} Datadog Receiver
 
 1. Add the following `otelcol.processor.batch` component to your configuration file.
 
@@ -122,18 +122,21 @@ The [otelcol.exporter.otlp][] component is responsible for delivering OTLP data
     - _`<USERNAME>`_: The basic authentication username.
     - _`<PASSWORD>`_: The basic authentication password or API key.
 
-## Configure Datadog Agent to forward metrics to the Datadog Receiver
+## Configure Datadog Agent to forward telemetry to the {{% param "PRODUCT_NAME" %}} Datadog Receiver
 
-You can set up your Datadog Agent to forward Datadog metrics simultaneously to {{< param "PRODUCT_NAME" >}} and Datadog.
+You can set up your Datadog Agent to forward Datadog metrics and traces simultaneously to {{< param "PRODUCT_NAME" >}} and Datadog.
 
 We recommend this approach for current Datadog users who want to try using {{< param "PRODUCT_NAME" >}}.
 
-1. Add the following environment variable to your datadog-agent installation.
+1. Add the following environment variables to your Datadog-agent installation.
 
    ```bash
    DD_ADDITIONAL_ENDPOINTS='{"http://<DATADOG_RECEIVER_HOST>:<DATADOG_RECEIVER_PORT>": ["datadog-receiver"]}'
+   DD_APM_ADDITIONAL_ENDPOINTS='{"http://<DATADOG_RECEIVER_HOST>:<DATADOG_RECEIVER_PORT>": ["datadog-receiver"]}'
    ```
 
+   `DD_ADDITIONAL_ENDPOINTS` is used for forwarding metrics, whereas `DD_APM_ADDITIONAL_ENDPOINTS` is for traces.
+
    Replace the following:
 
     - _`<DATADOG_RECEIVER_HOST>`_: The hostname where the {{< param "PRODUCT_NAME" >}} receiver is found.
@@ -154,9 +157,10 @@ Or by setting an environment variable:
    DD_DD_URL='{"http://<DATADOG_RECEIVER_HOST>:<DATADOG_RECEIVER_PORT>": ["datadog-receiver"]}'
    ```
 
-## Run {{% param "PRODUCT_NAME" %}} with the Datadog Receiver
+## Run {{% param "PRODUCT_NAME" %}}
 
-Some of the components used here are experimental. In order to run them, you need to start {{< param "PRODUCT_NAME" >}} with additional command line flags:
+The `otelcol.receiver.datadog` component is experimental.
+To use this component, you need to start {{< param "PRODUCT_NAME" >}} with additional command line flags:
 
    ```bash
    alloy run config.alloy --stability.level=experimental