DOCS-10874 Mention replica set names requirement

Author: kallimachos

source/tutorial/deploy-shard-cluster.txt

@@ -20,8 +20,8 @@ Overview
 This tutorial involves creating a new sharded cluster that consists of a
 :binary:`~bin.mongos`, the config server replica set, and two shard replica sets.
 
-For instructions specific to sharding a collection, see 
-:ref:`deploy-hashed-sharded-cluster-shard-collection` or 
+For instructions specific to sharding a collection, see
+:ref:`deploy-hashed-sharded-cluster-shard-collection` or
 :ref:`deploy-ranged-sharded-cluster-shard-collection`.
 
 Considerations
@@ -30,9 +30,9 @@ Considerations
 Connectivity
 ~~~~~~~~~~~~
 
-Each member of a sharded cluster must be able to connect to *all* other 
-members in the cluster. This includes all shards and config servers. 
-Ensure that network and security systems, including all interface and 
+Each member of a sharded cluster must be able to connect to *all* other
+members in the cluster. This includes all shards and config servers.
+Ensure that network and security systems, including all interface and
 firewalls, allow these connections.
 
 CloudManager and OpsManager
@@ -80,9 +80,9 @@ For details on using x.509 for client authentication, see
 Host Identifier
 ~~~~~~~~~~~~~~~
 
-If you use either ``localhost`` or ``127.0.0.1`` as the hostname portion of 
-any host identifier, you *must* use that identifier as the host setting 
-for any other MongoDB component in the cluster. 
+If you use either ``localhost`` or ``127.0.0.1`` as the hostname portion of
+any host identifier, you *must* use that identifier as the host setting
+for any other MongoDB component in the cluster.
 
 For example, the :method:`sh.addShard()` method takes a ``host`` parameter for
 the hostname of the target shard. If you set ``host`` to ``localhost``, you
@@ -105,6 +105,11 @@ For a production deployment, deploy a config server replica set with at
 least three members. For testing purposes, you can create a
 single-member replica set.
 
+.. note::
+
+   The config server replica set must not use the same name as any of the
+   shard replica sets.
+
 .. include:: /includes/steps/deploy-sharded-cluster-config-server-noauth.rst
 
 Once the config server replica set (CSRS) is initiated and up, proceed
@@ -117,6 +122,11 @@ For a production deployment, use a replica set with at least three
 members. For testing purposes, you can create a single-member replica
 set.
 
+.. note::
+
+   Shard replica sets must not use the same name as the config server replica
+   set.
+
 .. include:: /includes/steps/deploy-sharded-cluster-shard-replica-noauth.rst
 
 .. _sharding-setup-start-mongos:
@@ -181,7 +191,7 @@ Shard a Collection
 
 This section contains an overall description of the sharding process.
 
-For instructions specific to :ref:`sharding-ranged` sharding, 
+For instructions specific to :ref:`sharding-ranged` sharding,
 see :ref:`deploy-ranged-sharded-cluster-shard-collection`.
 
 For instructions specific to :ref:`sharding-hashed` sharding,