Add description of additional attributes for nodes, bonds, NICs

Add the desctription to the Fuel plugin SDK guide

Change-Id: I573ffd6f91d37b534cf1db88910833ac71279751

plugindocs/fuel-plugin-sdk-guide/create-plugin.rst

@@ -21,7 +21,8 @@ This section includes the following topics:
    create-plugin/actions-existing-roles.rst
    create-plugin/plugin-settings.rst
    create-plugin/plugin-node-roles.rst
+   create-plugin/plugin-attributes.rst
    create-plugin/modify-ui.rst
    create-plugin/plugin-repos.rst
    create-plugin/add-driverlog.rst
-   create-plugin/plugin-versioning-system.rst
+   create-plugin/plugin-versioning-system.rst

plugindocs/fuel-plugin-sdk-guide/create-plugin/plugin-attributes.rst

@@ -0,0 +1,70 @@
+
+.. _plugin-attributes:
+
+Additional attributes for NICs, bonds, and nodes
+------------------------------------------------
+
+You can provide additional attributes for NICs, bonds, and nodes. This is
+useful for a plugin providing "per interface" or "per node" technology.
+
+An example of this use case is virtual functions support for vRouter on
+each network interface in Contrail.
+
+**To provide additional attributes for NICs:**
+
+Edit the ``nic_attributes.yaml`` file with the additional attributes.
+
+**Example:**
+
+.. code-block:: yaml
+
+    attribute_a:
+      label: "NIC attribute A"
+      description: "Your description"
+      type: "text"
+      value: ""
+    attribute_b:
+      label: "NIC attribute B"
+      description: "Your description"
+      type: "checkbox"
+      value: false
+
+**To provide additional attributes for bonds:**
+
+Edit the ``bond_attributes.yaml`` file with the additional attributes.
+
+**Example:**
+
+.. code-block:: yaml
+
+    attribute_a:
+      label: "Bond attribute A"
+      description: "Your description"
+      type: "text"
+      value: ""
+    attribute_b:
+      label: "Bond attribute B"
+      description: "Your description"
+      type: "checkbox"
+      value: false
+
+**To provide additional attributes for nodes:**
+
+Edit the ``node_attributes.yaml`` file with the additional attributes.
+
+**Example:**
+
+.. code-block:: yaml
+
+    plugin_section_a:
+      metadata:
+        group: "your_new_section"
+        label: "Section A"
+      attribute_a:
+        label: "Node attribute A for section A"
+        description: "Your description"
+        type: "text"
+      attribute_b:
+        label: "Node attribute B for section A"
+        description: "Your description"
+        type: "checkbox"