docs: improve dynamic reloading

docs/content/feature/dynamic-reloading.md

@@ -3,4 +3,25 @@ title: "Dynamic Reloading"
 since: "1.0"
 ---
 
-fabio watches services in consul and reloads its configuration on every change without interrupting existing connections.
+fabio builds the routing table from the Consul service registrations, health
+check status and the user provided `route` commands stored in the Consul KV
+store. This is **the** core feature of fabio - the reason it exists.
+
+The cluster wide state is stored in the Consul Raft log which provides a
+consistent view of the available and healthy services in the cluster. 
+
+When the Raft log changes fabio is notified and downloads the list of
+healthy services and the user defined routes from the KV store and re-builds
+the routing table.
+
+Once the new routing table has been built it is atomically swapped with the
+active routing table without any service interruption. Existing connections
+remain open and running requests are served even if the new routing table no
+longer contains that route. 
+
+Registering or de-registering a service, setting a node to maintenance mode,
+failing or passing of a health check for a service, or writing data into the
+Consul KV store all trigger an automatic reload of the fabio routing table for
+all fabio nodes in the cluster.
+
+This all happens automatically, with no downtime, or manual intervention.