Clarify AG relationship to Resource Governor

Author: MikeRayMSFT

docs/database-engine/availability-groups/windows/contained-availability-groups-overview.md

@@ -136,6 +136,10 @@ Currently, the following [!INCLUDE [ssnoversion-md](../../../includes/ssnoversio
 
 Resource Governor works at the instance level. Resource Governor with a contained availability group isn't applicable.
 
+Resource Governor configuration DDL commands have no effect when executed on a contained availability group connection.
+
+If Resource Governor is enabled via an instance connection, it has no effect on the contained availability group connections.
+
 ### Change data capture
 
 Change data capture (CDC) is implemented as SQL Agent jobs, so the SQL Agent needs to be running on all instances with replicas in the contained AG.

docs/database-engine/availability-groups/windows/prereqs-restrictions-recommendations-always-on-availability.md

@@ -57,7 +57,9 @@ To support the [!INCLUDE [ssHADR](../../../includes/sshadr-md.md)] feature, ensu
 
 - **Sufficient disk space:** Every computer on which a server instance hosts an availability replica must possess sufficient disk space for all the databases in the availability group. Keep in mind that as primary databases grow, their corresponding secondary databases grow the same amount.
 
-- **Identical disk layout:** Every computer on which a server instance hosts an availability replica should have an identical disk layout (with exact disk drive letters and sizes) to ensure file paths for database files (mdf, ldf) are mirrored, preventing complications during seeding and synchronization.  Review [Restrictions (availability databases)](#RestrictionsDb) for disk layouts that differ. 
+- **Identical disk layout:** Every computer on which a server instance hosts an availability replica should have an identical disk layout (with exact disk drive letters and sizes) to ensure file paths for database files (mdf, ldf) are mirrored, preventing complications during seeding and synchronization.  Review [Restrictions (availability databases)](#RestrictionsDb) for disk layouts that differ.
+
+- **Resource Governor configuration**: If you are using Resource Governor, use the same Resource Governor configuration on all instances that host availability group replicas.
 
 ### <a id="PermissionsWindows"></a> Permissions (Windows system)
 

docs/relational-databases/resource-governor/resource-governor.md

@@ -49,6 +49,7 @@ Resource governor has the following limitations:
 - Very short queries, such as queries in some OLTP workloads, might not use CPU long enough to apply CPU bandwidth controls. This might skew CPU usage statistics and limit the effectiveness of CPU resource governance.
 - The ability to govern physical I/O applies only to user operations and not system tasks. System tasks perform transaction log, checkpoint, and lazy writer I/O. Resource governor governs user physical reads I/O but not write I/O performed by system tasks.
 - You can't modify resource governance controls for the `internal` resource pool and workload group.
+- Resource Governor works at the instance level. Resource Governor with a contained availability group isn't applicable.
 
 ## Resource concepts