Doc syntax error and expressions updates

Correct syntax error for Deployment Philosophy doc.
Update node types descriptions for more unified in doc Production
architecture.

Change-Id: I9266a72eb88d9c4c52673bbdecc952b684a56d12

doc/deployment-philosophy.rst

@@ -9,8 +9,8 @@ Overview
 
 Kolla has an objective to replace the inflexible, painful, resource-intensive
 deployment process of OpenStack with a flexible, painless, inexpensive
-deployment process. Often to deploy OpenStack at the 100+ node scale small
-businesses may require means building a team of OpenStack professionals to
+deployment process. Often to deploy OpenStack at the 100+ nodes scale, small
+businesses may require building a team of OpenStack professionals to
 maintain and manage the OpenStack deployment. Finding people experienced in
 OpenStack deployment is very difficult and expensive, resulting in a big
 barrier for OpenStack adoption. Kolla seeks to remedy this set of problems by

doc/production-architecture-guide.rst

@@ -14,18 +14,18 @@ Node types and services running on them
 A basic Kolla inventory consists of several types of nodes, known in Ansible as
 ``groups``.
 
-* Controller - This is the cloud controller node. It hosts control services
+* Controller - Cloud controller nodes which host control services
   like APIs and databases. This group should have odd number of nodes for
   quorum.
 
-* Network - This is the network node. It will host Neutron agents along with
+* Network - Network nodes host Neutron agents along with
   haproxy / keepalived. These nodes will have a floating ip defined in
   ``kolla_internal_vip_address``.
 
-* Compute - These are servers for compute services. This is where guest VMs
+* Compute - Compute nodes for compute services. This is where guest VMs
   live.
 
-* Storage - Storage servers, for cinder-volume, LVM or ceph-osd.
+* Storage - Storage nodes, for cinder-volume, LVM or ceph-osd.
 
 Network configuration
 =====================