Add documentation for routes (#2496)

* Add documentation for routes

* Rename exit-node to routes and add redirects
* Add a new section on subnet routers
* Extend the existing exit-node documentation
* Describe auto approvers for subnet routers and exit nodes
* Provide ACL examples for subnet routers and exit nodes
* Describe HA and its current limitations
* Add a troubleshooting section with IP forwarding

* Update features page for 0.26

Add auto approvers and link to our documentation if available.

* Prefer the console lexer when commandline and output mixed

Author: nblock

CHANGELOG.md

@@ -16,15 +16,15 @@ this, the CLI and API has been simplified to reflect the changes;
 
 ```console
 $ headscale nodes list-routes
-ID | Hostname           | Approved | Available       | Serving
+ID | Hostname           | Approved | Available       | Serving (Primary)
 1  | ts-head-ruqsg8     |          | 0.0.0.0/0, ::/0 |
 2  | ts-unstable-fq7ob4 |          | 0.0.0.0/0, ::/0 |
 
 $ headscale nodes approve-routes --identifier 1 --routes 0.0.0.0/0,::/0
 Node updated
 
 $ headscale nodes list-routes
-ID | Hostname           | Approved        | Available       | Serving
+ID | Hostname           | Approved        | Available       | Serving (Primary)
 1  | ts-head-ruqsg8     | 0.0.0.0/0, ::/0 | 0.0.0.0/0, ::/0 | 0.0.0.0/0, ::/0
 2  | ts-unstable-fq7ob4 |                 | 0.0.0.0/0, ::/0 |
 ```
@@ -106,6 +106,8 @@ working in v1 and not tested might be broken in v2 (and vice versa).
   [#2503](https://github.com/juanfont/headscale/pull/2503)
 - Restore support for "Override local DNS"
   [#2438](https://github.com/juanfont/headscale/pull/2438)
+- Add documentation for routes
+  [#2496](https://github.com/juanfont/headscale/pull/2496)
 
 ## 0.25.1 (2025-02-25)
 

docs/about/features.md

@@ -2,27 +2,30 @@
 
 Headscale aims to implement a self-hosted, open source alternative to the Tailscale control server. Headscale's goal is
 to provide self-hosters and hobbyists with an open-source server they can use for their projects and labs. This page
-provides on overview of headscale's feature and compatibility with the Tailscale control server:
+provides on overview of Headscale's feature and compatibility with the Tailscale control server:
 
 - [x] Full "base" support of Tailscale's features
 - [x] Node registration
     - [x] Interactive
     - [x] Pre authenticated key
-- [x] [DNS](https://tailscale.com/kb/1054/dns)
+- [x] [DNS](../ref/dns.md)
     - [x] [MagicDNS](https://tailscale.com/kb/1081/magicdns)
     - [x] [Global and restricted nameservers (split DNS)](https://tailscale.com/kb/1054/dns#nameservers)
     - [x] [search domains](https://tailscale.com/kb/1054/dns#search-domains)
-    - [x] [Extra DNS records (headscale only)](../ref/dns.md#setting-extra-dns-records)
+    - [x] [Extra DNS records (Headscale only)](../ref/dns.md#setting-extra-dns-records)
 - [x] [Taildrop (File Sharing)](https://tailscale.com/kb/1106/taildrop)
-- [x] Routing advertising (including exit nodes)
+- [x] [Routes](../ref/routes.md)
+    - [x] [Subnet routers](../ref/routes.md#subnet-router)
+    - [x] [Exit nodes](../ref/routes.md#exit-node)
 - [x] Dual stack (IPv4 and IPv6)
 - [x] Ephemeral nodes
 - [x] Embedded [DERP server](https://tailscale.com/kb/1232/derp-servers)
 - [x] Access control lists ([GitHub label "policy"](https://github.com/juanfont/headscale/labels/policy%20%F0%9F%93%9D))
     - [x] ACL management via API
-    - [x] `autogroup:internet`
-    - [ ] `autogroup:self`
-    - [ ] `autogroup:member`
+    - [x] Some [Autogroups](https://tailscale.com/kb/1396/targets#autogroups), currently: `autogroup:internet`
+    - [x] [Auto approvers](https://tailscale.com/kb/1337/acl-syntax#auto-approvers) for [subnet
+      routers](../ref/routes.md#automatically-approve-routes-of-a-subnet-router) and [exit
+      nodes](../ref/routes.md#automatically-approve-an-exit-node-with-auto-approvers)
 * [ ] Node registration using Single-Sign-On (OpenID Connect) ([GitHub label "OIDC"](https://github.com/juanfont/headscale/labels/OIDC))
     - [x] Basic registration
     - [x] Update user profile from identity provider

docs/ref/dns.md

@@ -76,14 +76,14 @@ hostname and port combination "http://hostname-in-magic-dns.myvpn.example.com:30
 
     === "Query with dig"
 
-        ```shell
+        ```console
         dig +short grafana.myvpn.example.com
         100.64.0.3
         ```
 
     === "Query with drill"
 
-        ```shell
+        ```console
         drill -Q grafana.myvpn.example.com
         100.64.0.3
         ```