Document bootstrapping service setup

Describe how to deploy teh bootstrapping service inside an AS

* HTTP server

* discovery mechanism

* Endhost usage

content/config/setup_bootstrap.md

@@ -0,0 +1,135 @@
+---
+title: Setup automatic endhost configuration
+parent: Configuration
+nav_order: 40
+---
+
+# Setup automatic endhost configuration
+
+To have endhosts automatically join the SCION AS rather than configure the
+endhost manually, you can deploy the bootstrapping service.
+
+## Deploy the Discovery Service
+
+The Discovery Service is a static HTTP server hosting the `topology.json` file.
+We describe a sample setup using nginx but any webserver with the same URL paths
+will work.
+
+Install nginx on the system you want to use as the discovery server:
+
+```shell
+sudo apt-get install nginx
+```
+
+Put the following configuration into `/etc/nginx/nginx.conf`:
+
+```
+user www-data www-data;
+worker_processes  auto;
+
+events {
+    worker_connections  1024;
+}
+
+http {
+    include       mime.types;
+
+    access_log  /var/log/nginx/access.log;
+    error_log   /var/log/nginx/error.log;
+
+    server_tokens off;
+    types_hash_max_size 4096;
+    server_names_hash_bucket_size 128;
+
+    keepalive_requests 32;
+    keepalive_timeout 60s;
+
+    server {
+        listen      *:8041;
+        listen      [::]:8041;
+
+        location / {
+            root /srv/http;
+            autoindex on;
+        }
+    }
+}
+```
+
+Start the nginx webserver:
+
+```shell
+sudo systemctl enable --now nginx
+```
+
+Put the `topology.json` file of your AS into
+`/srv/http/discovery/v1/static/endhost.json`
+
+Check that the topology can be fetched by accessing
+`http://<yourdiscoveryserver>:8041/discovery/v1/static/endhost.json`. This
+should serve your topology file.
+
+## Configure a Discovery Mechanism
+
+Choose at least one of the described options:
+
+### DHCP configuration
+
+Configure your local DHCP server to provide clients with the IP address of your
+discovery service as option 72 "Default WWW server". The concrete configuration
+depends on your DHCP server. For `dnsmasq` add the following line to
+`/etc/dnsmasq.conf`: `dhcp-option=72,<yourdiscoveryserverIP>`
+
+### mDNS configuration
+
+Install an mDNS daemon on your machine:
+
+```shell
+sudo apt-get install avahi-daemon
+```
+
+Put the configuration to `/etc/avahi/services/sciondiscovery.xml`:
+
+```xml
+<?xml version="1.0" standalone='no'?>
+<!DOCTYPE service-group SYSTEM "avahi-service.dtd">
+<service-group>
+  <name replace-wildcards="yes">%h</name>
+  <service>
+    <type>_sciondiscovery._tcp</type>
+    <port>8041</port>
+  </service>
+</service-group>
+```
+
+```shell
+sudo systemctl enable --now avahi-daemon
+```
+
+### DNS Configuration
+
+Configure your DNS domain (if you have one) to contain the following records:
+
+Using DNS SD:
+```
+_sciondiscovery._tcp.<yourdomain> IN SRV 10 10 8041 <yourdiscoveryserver>
+<yourdiscoveryserver> IN A <yourdiscoveryserverIP>
+```
+
+OR using DNS S-NAPTR:
+
+```
+<yourdomain> IN NAPTR 10 10 "a" "x-sciondiscovery:tcp" <yourdiscoveryserver>
+<yourdiscoveryserver> IN A <yourdiscoveryserverIP>
+```
+
+## Configure the endhost
+
+On the endhost you have to make sure the bootstrapper runs before sciond is
+started, so that the bootstrapper can generate the configuration of sciond
+beforehand.
+
+```shell
+sudo apt-get install scion-bootstrapper
+sudo systemctl enable --now scion-bootstrapper.service
+```