Clarify description of deployment planners

Clarify description of deployment planners

Author: rajujith

source/adminguide/deployment_planners.rst

@@ -18,7 +18,7 @@ Deployment Planners
 ======================
 
 
-Deployment planners determine *how and where instances* are placed across clusters within a zone.  
+Deployment planners determine how instances are allocated within a zone based on configuration settings.
 A planner builds and orders a *list of candidate clusters* based on a placement strategy such as available capacity, user dispersion, or pod concentration.  
 This ordered list is then passed to the *host allocator*, which attempts to deploy the instance following the planner’s priority order.