Updated inventory template in install guide

Updated the inventory file template in install guide to cover
new group structure.
Just copy-paste of current inventory/hosts.yml
same as before.

Change-Id: Iade5f8120b06bccebf8f156b2637998722ecfa07
Issue-ID: OOM-1778
Signed-off-by: Michal Zegan <m.zegan@samsung.com>
diff --git a/docs/InstallGuide.rst b/docs/InstallGuide.rst
index 95b5749..7e8ebf0 100644
--- a/docs/InstallGuide.rst
+++ b/docs/InstallGuide.rst
@@ -168,20 +168,29 @@
 
         # This is group of hosts which are/will be part of Kubernetes cluster.
         kubernetes:
-          hosts:
-            kubernetes-node-1:
-              ansible_host: 10.8.8.19
-              #ip of the node that it uses for communication with k8s cluster.
-              cluster_ip: 10.8.8.19
+          children:
+            # This is a group of hosts containing kubernetes worker nodes.
+            kubernetes-node:
+              hosts:
+                kubernetes-node-1:
+                  ansible_host: 10.8.8.19
+                  #ip of the node that it uses for communication with k8s cluster.
+                  cluster_ip: 10.8.8.19
 
-        # This is a group of hosts that are to be used as kubernetes control plane nodes.
-        # This means they host kubernetes api server, controller manager and scheduler.
-        # This example uses infra for this purpose, however note that any
-        # other host could be used including kubernetes nodes.
-        # cluster_ip needs to be set for hosts used as control planes.
-        kubernetes-control-plane:
-          hosts:
-            infrastructure-server
+            # Group of hosts containing etcd cluster nodes.
+            # Defaults to infra.
+            kubernetes-etcd:
+              hosts:
+                infrastructure-server
+
+            # This is a group of hosts that are to be used as kubernetes control plane nodes.
+            # This means they host kubernetes api server, controller manager and scheduler.
+            # This example uses infra for this purpose, however note that any
+            # other host could be used including kubernetes nodes.
+            # cluster_ip needs to be set for hosts used as control planes.
+            kubernetes-control-plane:
+              hosts:
+                infrastructure-server
 
         nfs-server:
           hosts:
@@ -222,37 +231,43 @@
         infrastructure:
           hosts:
             infrastructure-server:
-              ansible_host: 10.8.8.100
+              ansible_host: 10.8.8.13
               #IP used for communication between infra and kubernetes nodes, must be specified.
               cluster_ip: 10.8.8.100
 
         # This is group of hosts which are/will be part of Kubernetes cluster.
         kubernetes:
-          hosts:
-            kubernetes-node-1:
-              ansible_host: 10.8.8.101
-              #ip of the node that it uses for communication with k8s cluster.
-              cluster_ip: 10.8.8.101
-            kubernetes-node-2:
-              ansible_host: 10.8.8.102
-              #ip of the node that it uses for communication with k8s cluster.
-              cluster_ip: 10.8.8.102
-            kubernetes-node-3:
-              ansible_host: 10.8.8.103
-              #ip of the node that it uses for communication with k8s cluster.
-              cluster_ip: 10.8.8.103
+          children:
+            # This is a group of hosts containing kubernetes worker nodes.
+            kubernetes-node:
+              hosts:
+                kubernetes-node-1:
+                  ansible_host: 10.8.8.101
+                  #ip of the node that it uses for communication with k8s cluster.
+                  cluster_ip: 10.8.8.101
+                kubernetes-node-2:
+                  ansible_host: 10.8.8.102
+                  #ip of the node that it uses for communication with k8s cluster.
+                  cluster_ip: 10.8.8.102
+                kubernetes-node-3:
+                  ansible_host: 10.8.8.103
+                  #ip of the node that it uses for communication with k8s cluster.
+                  cluster_ip: 10.8.8.103
 
-        # This is a group of hosts that are to be used as kubernetes control plane nodes.
-        # This means they host kubernetes api server, controller manager and scheduler.
-        # This example uses infra for this purpose, however note that any
-        # other host could be used including kubernetes nodes.
-        # cluster_ip needs to be set for hosts used as control planes.
-        kubernetes-control-plane:
-          hosts:
-            infrastructure-server
-              ansible_host: 10.8.8.100
-              #IP used for communication between infra and kubernetes nodes, must be specified.
-              cluster_ip: 10.8.8.100
+            # Group of hosts containing etcd cluster nodes.
+            # Defaults to infra.
+            kubernetes-etcd:
+              hosts:
+                infrastructure-server
+
+            # This is a group of hosts that are to be used as kubernetes control plane nodes.
+            # This means they host kubernetes api server, controller manager and scheduler.
+            # This example uses infra for this purpose, however note that any
+            # other host could be used including kubernetes nodes.
+            # cluster_ip needs to be set for hosts used as control planes.
+            kubernetes-control-plane:
+              hosts:
+                infrastructure-server
 
         nfs-server:
           hosts: