Improve documentation for the new service-parameter DNS local

Change-Id: I4ada1e15b4a40cb5047abb38a0e1cf65d15e821b
Signed-off-by: Suzana Fernandes <Suzana.Fernandes@windriver.com>

doc/source/system_configuration/kubernetes/user-host-entries-configuration-9ad4c060eb15.rst

@@ -4,11 +4,9 @@
 User-Defined Host Entries Configuration
 =======================================
 
-You can configure user-defined host entries for external resources that are not
+You can configure user-defined host entries for external resources. This
-maintained by |DNS| records resolvable by the external |DNS| server(s) (i.e.
+capability enables the configuration of local host records, supplementing
-``nameservers`` in ``system dns-show/dns-modify``). This functionality enables
+hosts resolvable by external |DNS| server(s).
-the configuration of local host records, supplementing hosts resolvable by
-external |DNS| server(s).
 
 .. only:: starlingx
 
@@ -21,7 +19,8 @@ external |DNS| server(s).
       :start-after: host-entries-start
       :end-before: host-entries-end
 
-The following methods are enabled to configure user host records/entries.
+The following methods are enabled to configure user host records/entries and
+local |DNS| entries.
 
 -  :ref:`Configure User-Defined Host Entries During Bootstrap <bootstrap-user-host-entries-configuration-9ad4c060eb15>`
 
@@ -33,6 +32,7 @@ The following methods are enabled to configure user host records/entries.
       :start-after: deploy-manager-ref-start
       :end-before: deploy-manager-ref-end
 
+-  :ref:`Configure User-Defined Local DNS Scope Entries <local-dns-entries-configuration-9ad4c060eb15>`
 
 .. _bootstrap-user-host-entries-configuration-9ad4c060eb15:
 
@@ -81,8 +81,8 @@ following procedure:
 
     .. code-block:: none
 
-        system service-parameter-add dns host-record <host-record-name>=<fqdn>[,<fqdn>...],[<IPv4-address>],[<IPv6-address>][,<TTL>]
+        ~(keystone_admin)]$ system service-parameter-add dns host-record <host-record-name>=<fqdn>[,<fqdn>...],[<IPv4-address>],[<IPv6-address>][,<TTL>]
-        system service-parameter-apply dns
+        ~(keystone_admin)]$ system service-parameter-apply dns
 
     Where fqdn = fully qualified domain name.
 
@@ -90,7 +90,7 @@ following procedure:
 
     .. code-block:: none
 
-        system service-parameter-add dns host-record test-server1=host1,testserver1.com,127.0.0.1
+        ~(keystone_admin)]$ system service-parameter-add dns host-record test-server1=host1,testserver1.com,127.0.0.1
 
     .. image:: figures/add-parameter.png
          :width: 800
@@ -99,8 +99,8 @@ following procedure:
 
     .. code-block:: none
 
-        system service-parameter-modify dns host-record <host-record-name>:<fqdn>[,<fqdn>...],[<IPv4-address>],[<IPv6-address>][,<TTL>]
+        ~(keystone_admin)]$ system service-parameter-modify dns host-record <host-record-name>:<fqdn>[,<fqdn>...],[<IPv4-address>],[<IPv6-address>][,<TTL>]
-        system service-parameter-apply dns
+        ~(keystone_admin)]$ system service-parameter-apply dns
 
     Where fqdn = fully qualified domain name.
 
@@ -111,7 +111,7 @@ following procedure:
 
     .. code-block:: none
 
-        system service-parameter-modify dns host-record test-server1=host1,host,testserver1.com,127.0.0.1
+        ~(keystone_admin)]$ system service-parameter-modify dns host-record test-server1=host1,host,testserver1.com,127.0.0.1
 
     .. image:: figures/modify-parameter.png
          :width: 800
@@ -123,7 +123,7 @@ following procedure:
 
         .. code-block:: none
 
-            system service-parameter-list | grep host-record
+            ~(keystone_admin)]$ system service-parameter-list | grep host-record
 
         Copy the |UUID| of the parameter that needs to be deleted.
 
@@ -131,13 +131,13 @@ following procedure:
 
         .. code-block:: none
 
-            system service-parameter-delete <uuid>
+            ~(keystone_admin)]$ system service-parameter-delete <uuid>
 
         For example:
 
         .. code-block:: none
 
-            system service-parameter-delete  a24e147f-2d13-4d7b-a8e7-47a1d77b95b5
+            ~(keystone_admin)]$ system service-parameter-delete  a24e147f-2d13-4d7b-a8e7-47a1d77b95b5
 
 
 .. _deployment_manager:
@@ -147,3 +147,95 @@ following procedure:
    .. include:: /_includes/user-host-entries-configuration-9ad4c060eb15.rest
       :start-after: deploy-manager-start
       :end-before: deploy-manager-end
+
+.. _local-dns-entries-configuration-9ad4c060eb15:
+
+Configure User-Defined Local DNS Scope Entries
+----------------------------------------------
+
+You can configure user-defined domain entries within the local |DNS| scope to
+prevent DNS queries for those domains from being forwarded to external DNS
+server(s) (i.e. ``nameservers`` in ``system dns-show/dns-modify``).
+
+This capability enhances the ``User-Defined Host Entries Configuration``by
+ensuring that resolution of these entries occurs strictly within the local DNS
+scope (for example, resolving ``registry.central`` in subcloud environments).
+
+This setup is especially beneficial for systems using a single IP stack
+(either IPv4 or IPv6). If the system uses only IPv4 and receives |DNS| queries
+for both IPv4 and IPv6 for ``registry.central``, ``dnsmasq`` can respond locally
+with the IPv4 record and disregard the IPv6 query.
+
+Without this configuration, IPv6 queries would be unnecessarily forwarded to
+external |DNS| server(s), causing delays in resolution and impacting application
+performance.
+
+.. only:: starlingx
+
+   User-defined DNS local scope entries can be configured post-deployment.
+
+.. _CLI-local-dns-entries-configuration-9ad4c060eb15:
+
+Configure User-Defined Local DNS Scope Entries via System Inventory API/CLI
+***************************************************************************
+
+After system deployment, update |DNS| local scope entries using the CLI. Source
+the script ``/etc/platform/openrc`` to obtain administrative privileges and use
+the following procedure:
+
+.. rubric:: |proc|
+
+#.  Use the following command syntax to add the parameter.
+
+    .. code-block:: none
+
+        ~(keystone_admin)]$ system service-parameter-add dns local <local-scope-name>=<domain>
+        ~(keystone_admin)]$ system service-parameter-apply dns
+
+    Example:
+
+    .. code-block:: none
+
+        ~(keystone_admin)]$ system service-parameter-add dns local test-domain=host.domain
+
+    .. image:: figures/add-dns-local-parameter.png
+         :width: 800
+
+#.  Use the following command syntax to modify the parameter.
+
+    .. code-block:: none
+
+        ~(keystone_admin)]$ system service-parameter-modify dns local <local-scope-name>=<new_domain>
+        ~(keystone_admin)]$ system service-parameter-apply dns
+
+    Example:
+
+    .. code-block:: none
+
+        ~(keystone_admin)]$ system service-parameter-modify dns local test-domain=host.domain2
+
+    .. image:: figures/modify-dns-local-parameter.png
+         :width: 800
+
+#.  Follow the steps below to delete the parameter.
+
+    #.  Run the command to display the service parameter list for ``dns local
+        service-parameter`` type.
+
+        .. code-block:: none
+
+            ~(keystone_admin)]$ system service-parameter-list | grep local
+
+        Copy the |UUID| of the parameter that needs to be deleted.
+
+    #.  Run the command to delete the entry.
+
+        .. code-block:: none
+
+            ~(keystone_admin)]$ system service-parameter-delete <uuid>
+
+        For example:
+
+        .. code-block:: none
+
+            ~(keystone_admin)]$ system service-parameter-delete 49318709-3bb9-4b47-9e9a-54ed79d731c3