Docs: making docs clearer on subpath (#82239)

* making docs clearer on subpath

* Update docs/sources/tutorials/run-grafana-behind-a-proxy/index.md

Co-authored-by: Joseph Perez <45749060+josmperez@users.noreply.github.com>

* Update docs/sources/tutorials/run-grafana-behind-a-proxy/index.md

Co-authored-by: Joseph Perez <45749060+josmperez@users.noreply.github.com>

* Update docs/sources/tutorials/run-grafana-behind-a-proxy/index.md

Co-authored-by: Joseph Perez <45749060+josmperez@users.noreply.github.com>

* Update docs/sources/tutorials/run-grafana-behind-a-proxy/index.md

Co-authored-by: Joseph Perez <45749060+josmperez@users.noreply.github.com>

---------

Co-authored-by: Joseph Perez <45749060+josmperez@users.noreply.github.com>

docs/sources/tutorials/run-grafana-behind-a-proxy/index.md

@@ -34,23 +34,9 @@ domain = example.com
 
 - Restart Grafana for the new changes to take effect.
 
-You can also serve Grafana behind a _sub path_, such as `http://example.com/grafana`.
+## Configure reverse proxy
 
-To serve Grafana behind a sub path:
-
-1. Include the sub path at the end of the `root_url`.
-1. Set `serve_from_sub_path` to `true`. Or, let proxy rewrite the path for you (refer to examples below).
-
-```bash
-[server]
-domain = example.com
-root_url = %(protocol)s://%(domain)s:%(http_port)s/grafana/
-serve_from_sub_path = true
-```
-
-Next, you need to configure your reverse proxy.
-
-## Configure NGINX
+### Configure NGINX
 
 [NGINX](https://www.nginx.com) is a high performance load balancer, web server, and reverse proxy.
 
@@ -129,7 +115,7 @@ server {
 }
 ```
 
-If your Grafana configuration does not set `serve_from_sub_path` to true then you need to add a rewrite rule to each location block:
+Add a rewrite rule to each location block:
 
 ```
  rewrite  ^/grafana/(.*)  /$1 break;
@@ -139,7 +125,7 @@ If your Grafana configuration does not set `serve_from_sub_path` to true then yo
 If Grafana is being served from behind a NGINX proxy with TLS termination enabled, then the `root_url` should be set accordingly. For example, if Grafana is being served from `https://example.com/grafana` then the `root_url` should be set to `https://example.com/grafana/` or `https://%(domain)s/grafana/` (and the corresponding `domain` should be set to `example.com`) in the `server` section of the Grafana configuration file. The `protocol` setting should be set to `http`, because the TLS handshake is being handled by NGINX.
 {{% /admonition %}}
 
-## Configure HAProxy
+### Configure HAProxy
 
 To configure HAProxy to serve Grafana under a _sub path_:
 
@@ -150,22 +136,15 @@ frontend http-in
 
 backend grafana_backend
   server grafana localhost:3000
-```
-
-If your Grafana configuration doesn't set `server.serve_from_sub_path` to `true`, then you must add a rewrite rule to the `backend grafana_backend` block:
-
-```diff
-backend grafana_backend
-+  # Requires haproxy >= 1.6
-+  http-request set-path %[path,regsub(^/grafana/?,/)]
-
-+  # Works for haproxy < 1.6
-+  # reqrep ^([^\ ]*\ /)grafana[/]?(.*) \1\2
+  # Requires haproxy >= 1.6
+  http-request set-path %[path,regsub(^/grafana/?,/)]
+  # Works for haproxy < 1.6
+  # reqrep ^([^\ ]*\ /)grafana[/]?(.*) \1\2
 
   server grafana localhost:3000
 ```
 
-## Configure IIS
+### Configure IIS
 
 > IIS requires that the URL Rewrite module is installed.
 
@@ -192,7 +171,7 @@ This is the rewrite rule that is generated in the `web.config`:
 
 See the [tutorial on IIS URL Rewrites](/tutorials/iis/) for more in-depth instructions.
 
-## Configure Traefik
+### Configure Traefik
 
 [Traefik](https://traefik.io/traefik/) Cloud Native Reverse Proxy / Load Balancer / Edge Router
 
@@ -240,6 +219,18 @@ http:
           - url: http://192.168.30.10:3000
 ```
 
-## Summary
+## Alternative for serving Grafana under a sub path
 
-In this tutorial you learned how to run Grafana behind a reverse proxy.
+**Warning:** You only need this, if you do not handle the sub path serving via your reverse proxy configuration.
+
+If you don't want or can't use the reverse proxy to handle serving Grafana from a _sub path_, you can set the config variable `server_from_sub_path` to `true`.
+
+1. Include the sub path at the end of the `root_url`.
+2. Set `serve_from_sub_path` to `true`:
+
+```bash
+[server]
+domain = example.com
+root_url = %(protocol)s://%(domain)s:%(http_port)s/grafana/
+serve_from_sub_path = true
+```