diff --git a/doc/source/configuration.rst b/doc/source/configuration.rst
index 0493f8f..9d580f0 100644
--- a/doc/source/configuration.rst
+++ b/doc/source/configuration.rst
@@ -630,6 +630,16 @@
     KEYSTONE_SERVICE_HOST=<KEYSTONE_IP_ADDRESS_FROM_REGION_ONE>
     KEYSTONE_AUTH_HOST=<KEYSTONE_IP_ADDRESS_FROM_REGION_ONE>
     REGION_NAME=RegionTwo
+    KEYSTONE_REGION_NAME=RegionOne
+
+In the devstack for RegionOne, we set REGION_NAME as RegionOne, so region of
+the services started in this devstack are registered as RegionOne. In devstack
+for RegionTwo, similarly, we set REGION_NAME as RegionTwo since we want
+services started in this devstack to be registered in RegionTwo. But Keystone
+service is started and registered in RegionOne, not RegionTwo, so we use
+KEYSTONE_REGION_NAME to specify the region of Keystone service.
+KEYSTONE_REGION_NAME has a default value the same as REGION_NAME thus we omit
+it in the configuration of RegionOne.
 
 Disabling Identity API v2
 +++++++++++++++++++++++++
diff --git a/stack.sh b/stack.sh
index 739d939..3de9af2 100755
--- a/stack.sh
+++ b/stack.sh
@@ -1020,7 +1020,7 @@
 export OS_PASSWORD=$ADMIN_PASSWORD
 export OS_PROJECT_NAME=admin
 export OS_PROJECT_DOMAIN_ID=default
-export OS_REGION_NAME=$REGION_NAME
+export OS_REGION_NAME=$KEYSTONE_REGION_NAME
 
 EOF
 
diff --git a/stackrc b/stackrc
index 17d6047..8858788 100644
--- a/stackrc
+++ b/stackrc
@@ -42,6 +42,12 @@
 # Specify region name Region
 REGION_NAME=${REGION_NAME:-RegionOne}
 
+# Specify name of region where identity service endpoint is registered.
+# When deploying multiple DevStack instances in different regions with shared
+# Keystone, set KEYSTONE_REGION_NAME to the region where Keystone is running
+# for DevStack instances which do not host Keystone.
+KEYSTONE_REGION_NAME=${KEYSTONE_REGION_NAME:-$REGION_NAME}
+
 # Specify which services to launch.  These generally correspond to
 # screen tabs. To change the default list, use the ``enable_service`` and
 # ``disable_service`` functions in ``local.conf``.