docs: re-add agent config doc (#1161)

Author: JTorreG

content/agent/configuration/configure-nginx-agent-features.md

@@ -0,0 +1,88 @@
+---
+title: Features configuration
+weight: 150
+toc: true
+nd-docs: DOCS-000
+nd-content-type: how-to
+---
+
+## Overview
+
+This guide describes the F5 NGINX Agent features, and how to enable and disable features using the NGINX Agent configuration file.
+
+## Before you begin
+
+Before you start, make sure that you have:
+
+- [NGINX Agent installed]({{< ref "/agent/installation-upgrade/" >}}) in your system.
+- Access to the NGINX Agent configuration file.
+
+## Features
+
+The following table lists the NGINX Agent features:
+
+{{< table "features" >}}
+| Feature Name     | Description                                                             | Default/Non-default |
+| ---------------- | ----------------------------------------------------------------------- | ------------------- |
+| registration     | Registering the NGINX Agent with the management plane.                  | Default             |
+| nginx-config-async | Enable the publishing and uploading of NGINX configurations from the management plane. | Default             |
+| metrics          | Enable collecting of NGINX metrics.                                     | Default             |
+| metrics-throttle | Batch metrics before sending.                                           | Non-default         |
+| metrics-sender   | Reports metrics over the gRPC connection.                               | Non-default         |
+| dataplane-status | Report the health of the NGINX Instance.                                | Default             |
+| process-watcher  | Observe changes to the NGINX process.                                   | Default             |
+| file-watcher     | Observe changes to the NGINX configuration or any changes to files on disk. | Default          |
+| activity-events  | Send NGINX or NGINX Agent related events to the management plane.       | Default             |
+| agent-api        | Enable the NGINX Agent REST API.                                        | Default             |
+{{< /table >}}
+
+## Use cases
+
+### Enable metrics only
+
+1. Access the NGINX instance: Connect using SSH to the VM or server where NGINX Agent is running.
+
+   `ssh user@your-nginx-instance`
+
+1. Open the NGINX Agent configuration file in a text editor.
+
+   `sudo vim /etc/nginx-agent/nginx-agent.conf`
+
+1. Add the features section: Add the following to the end of the configuration file if it doesn't already exist.
+
+   ```nginx
+   features:
+      - metrics
+      - metrics-throttle
+      - dataplane-status
+   ```
+
+1. Restart the NGINX Agent service to apply the changes.
+
+   `sudo systemctl restart nginx-agent`
+
+Once the steps have been completed, users will be able to view metrics data being sent but will not have the capability to push NGINX configuration changes.
+
+### Enable the publishing of NGINX configurations and disable the collection of metrics
+
+1. Access the NGINX instance: Connect using SSH to the VM or server where NGINX Agent is running.
+
+   `ssh user@your-nginx-instance`
+
+1. Open the NGINX Agent configuration file in a text editor.
+
+   `sudo vim /etc/nginx-agent/nginx-agent.conf`
+
+1. Add the fetures section: Add the following to the end of the configuration file if it doesn't already exist.
+
+   ```nginx
+   features:
+      - nginx-config-async
+      - dataplane-status
+      - file-watcher
+
+1. Restart the NGINX Agent service to apply the changes.
+
+   `sudo systemctl restart nginx-agent`
+
+Once the steps have been completed, users will be able to publish NGINX configurations but metrics data will not be collected by the NGINX Agent.