Update N1C getting started guide with instructions on how to enable metrics collection for a NGINX Plus API with SSL enabled

Author: dhurley

content/includes/use-cases/monitoring/enable-nginx-plus-api-with-ssl.md

@@ -0,0 +1,54 @@
+---
+nd-product: MSC
+nd-files:
+- content/nginx-one-console/getting-started.md
+---
+
+If SSL is enabled on the NGINX Plus API with self-signed certificates like this example:
+
+```nginx
+# This block enables the NGINX Plus API and dashboard with SSL
+# For configuration and security recommendations, see:
+# https://docs.nginx.com/nginx/admin-guide/monitoring/live-activity-monitoring/#configuring-the-api
+server {
+    # Change the listen port if 9000 conflicts
+    # (8080 is the conventional API port)
+    listen 9000 ssl;
+    ssl_certificate /etc/nginx/certs/nginx-selfsigned.crt; 
+    ssl_certificate_key /etc/nginx/certs/nginx-selfsigned.key;
+
+    location /api/ {
+        # To restrict write methods (POST, PATCH, DELETE), uncomment:
+        # limit_except GET {
+        #     auth_basic "NGINX Plus API";
+        #     auth_basic_user_file /path/to/passwd/file;
+        # }
+
+        # Enable API in write mode
+        api write=on;
+
+        # To restrict access by network, uncomment the following lines and set your network:
+        # allow 192.0.2.0/24;   # replace with your network
+        # allow 127.0.0.1/32;   # allow local NGINX Agent to call the NGINX Plus API to retrieve metrics
+        # deny  all;
+    }
+
+    # Serve the built-in dashboard at /dashboard.html
+    location = /dashboard.html {
+        root /usr/share/nginx/html;
+    }
+}
+```
+
+NGINX Agent configuration needs to be update with the following to enable the NGINX Agent to be able to call the NGINX Plus API.
+```
+data_plane_config:
+  nginx:
+    api_tls:
+      ca: "/etc/nginx/certs/nginx-selfsigned.crt"
+```
+
+Here is an example of how to generate self-signed certificates 
+```
+openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout /etc/nginx/certs/nginx-selfsigned.key -out /etc/nginx/certs/nginx-selfsigned.crt -subj "/CN=localhost" -addext "subjectAltName=IP:127.0.0.1"
+```

content/nginx-one-console/getting-started.md

@@ -163,6 +163,10 @@ The NGINX One Console dashboard relies on APIs for NGINX Plus and NGINX Open Sou
 
 {{< include "/use-cases/monitoring/enable-nginx-plus-api.md" >}}
 
+### Enable NGINX Plus API with SSL
+
+{{< include "/use-cases/monitoring/enable-nginx-plus-api-with-ssl.md" >}}
+
 ### Enable NGINX Open Source Stub Status API
 
 {{< include "/use-cases/monitoring/enable-nginx-oss-stub-status.md" >}}