Updated documentation

Author: Vincent PLANCHENAULT

doc/KUBERNETES.md

@@ -1,6 +1,26 @@
 # SafeScale: platform flavor K8S
 
-This document reports the specific choices made for the Kubernetes flavor of safescale platform.
+This document reports the specific choices made for the Kubernetes flavor of the command ```safescale platform```.
+
+## Differences between complexities (parameter ```--complexity|-C```)
+
+### ```Small``` complexity
+
+This complexity creates a cluster with a single gateway, a single Kubernetes master and a single Kubernetes node. There is no HA ability with it.
+
+### ```Normal``` complexity
+
+This flavor creates a cluster with 2 gateways (unless gateway failover is explicitly disabled with ```--disable gateway-failover```), 3 Kubernetes Masters and 3 Kubernetes Nodes, with HA ability :
+
+- the 2 gateways ensure Internet connectivity for the LAN.
+- the 3 Kubernetes Masters allows the failure of 1 master at a time.
+
+###  ```Large``` complexity
+
+This flavor creates a cluster with 2 gateways (unless gateway failover is explicitly disabled with ```--disable gateway-failover```), 5 Kubernetes Masters and 6 Kubernetes Nodes, with HA ability :
+
+- the 2 gateways ensure Internet connectivity for the LAN.
+- the 5 Kubernetes Masters allows the failure of 2 masters at a time.
 
 ## Port used for localAPIEndpoint