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Versions: 00 01 02 03

NETMOD Working Group                                               Q. Wu
Internet-Draft                                                    R. Tao
Intended status: Standards Track                               R. Ranade
Expires: December 31, 2019                                        Huawei
                                                           June 29, 2019


      NMDA Base Notification for Intent based configuration update
               draft-wu-netmod-base-notification-nmda-03

Abstract

   The Network Configuration Protocol (NETCONF)and RESTCONF provides
   mechanisms to manipulate configuration datastores.  NMDA introduces
   additional datastores for systems that support more advanced
   processing chains converting configuration to operational state.
   However, client applications are not able to be aware of common
   events in these additional datstores of the management system, such
   as a intended configuration state change in NETCONF server or
   RESTCONF server, that may impact management applications,especially
   when a server is managed by multiple clients or management
   applications.  This document define a YANG module that allows a
   client to receive additional notifications for some common system
   events pertaining to the Network Management Datastore Architecture
   (NMDA) defined in [RFC8342].

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on December 31, 2019.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.




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   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  NMDA Base Notifications for Intent based configuration Update   3
     2.1.  Overview  . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.2.  Data Model Design . . . . . . . . . . . . . . . . . . . .   5
     2.3.  Relation with NMDA Datastore Compare  . . . . . . . . . .   6
     2.4.  Definitions . . . . . . . . . . . . . . . . . . . . . . .   7
   3.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13
   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  14
   6.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  14
   7.  Normative References  . . . . . . . . . . . . . . . . . . . .  14
   Appendix A.  Changes between revisions  . . . . . . . . . . . . .  15
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  15

1.  Introduction

   The Network Configuration Protocol (NETCONF) [RFC6241] and RESTCONF
   [RFC8040] provides mechanisms to manipulate configuration datastores.
   NMDA introduces additional datastores (e.g.,<intended>,
   <operational>) for systems that support more advanced processing
   chains converting configuration to operational state.  However,
   client applications are not able to be aware of common events in
   those additional datastores of the management system, e.g., there are
   many background system activities (e.g.,system internal interactions
   with hardware, interaction with protocols or other devices) that
   happen during propagation of a configuration change to the software
   and hardware components of a system.  It is possible that some
   configuration could not be applied to <operational> due to either
   remnant Configuration, or missing resource, etc.  There is a need for
   user or an application (configuration) to know the origin of failed
   configuration node and the reason why the configuration changes were
   not applied.

   This document define a YANG module that allows a client to receive
   additional notifications for some common system events pertaining to



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   the Network Management Datastore Architecture (NMDA) defined in
   [RFC8342].  These notifications are designed to support the
   monitoring of the base system events within the server and not
   specific to any network management protocols such as NETCONF and
   RESTCONF.

   The solution presented in this document is backwards compatible with
   [RFC6470].

1.1.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

   The following terms are defined in [RFC8342] and are not redefined
   here:

   o  operational state datastore

   o  running configuration datastore

   o  intended configuration datastore

2.  NMDA Base Notifications for Intent based configuration Update

2.1.  Overview

   The YANG module in NETCONF Base Notifications [RFC6470] specifies the
   following 5 event notifications for the 'NETCONF' stream to notify a
   client application that the NETCONF server state has changed:

   o  netconf-config-change

   o  netconf-capability-change

   o  netconf-session-start

   o  netconf-session-end

   o  netconf-confirmed-commit

   These event notifications used within the 'NETCONF' stream are
   accessible to clients via the subscription mechanism described in
   [RFC5277].




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   This document introduces NMDA specific extension which allows a
   client to receive 1 notifications for additional common system events
   as follows:

   apply-configuration-updated:  Generated when a server with network
      management protocol support interacts with hardware and detects
      that a set of configurations are not applied or none of them are
      not applied.  Indicates the event and the current state of the
      applied configuration or data inconsistency issue between intended
      data initiated from the client and operational data saved in the
      server.  NMDA datastore compare [I-D.ietf-netmod-nmda-diff] can be
      used to trigger consistency data check, i.e.,indicate the source
      of configuration node and check which part of configuration data
      is applied or which part of configuration data is not applied.  A
      server MAY report events for non-NETCONF management sessions (such
      as RESTCONF,gPRC), using the 'session-id' value of zero.

   The following figure shows event notification sequence defined in
   this document.

                                    +----------------------------+
                                    |Server (device)             |
                                    |                            |
                                    |                            |
                                    |       +----------+         |
                                    |       | Intended |         |
   +------------+                   |       | datastore|         |
   |            |                   |       +----------+         |
   |+----------+|                   |           ^                |
   || Intended ||                   |           |                |
   || config   ||                   |           v                |
   |+----------+|                   |     +-------------+        |
   |            |<----------------------> |             |        |
   |   Client   |  <nmda-diff> rpc        |  NETCONF    |        |
   |    (app)   |                   |     |   engine    |        |
   |            |<----------------------  |             |        |
   |            | <intent-configuration   +-------------+        |
   |            |  -update> notification    /        \           |
   +------------+                   |      /          \          |
                                    |     /            \         |
                                    |+------------++---------+   |
                                    || Operational||system   |+  |
                                    ||  datastore ||software ||+ |
                                    ||            ||component||| |
                                    |+------------++---------+|| |
                                    |               +---------+| |
                                    |                +---------+ |
                                    +----------------------------+



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   These notification messages are accessible to clients via either the
   subscription mechanism described in [RFC5277] or dynamic subscription
   mechanism and configured subscription mechanism described in [I-
   D.ietf-netconf-netconf-event-notifications].

2.2.  Data Model Design

   The data model is defined in the ietf-nmda-notifications YANG module.
   Its structure is shown in the following figure.  The notation syntax
   follows [RFC8340].

     notifications:
        +---n intent-configuration-update
          +--ro app-tag?                string
          +--ro src-ds?                 identityref
          +--ro dst-ds?                 identifyref
          +--ro (filter-spec)?
          |  +--:(subtree-filter)
          |  |  +--ro subtree-filter?   <anydata>
          |  +--:(xpath-filter)
          |     +--ro xpath-filter?     yang:xpath1.0 {nc:xpath}?
          |--ro apply-result            enumeration
          +--ro fail-applied-object* [edit-id]
             +--ro edit-id      string
             +--ro operation    enumeration
             +--ro object?      ypatch:target-resource-offset
             +--ro value?       <anydata>
             +--ro errors
                +--ro error* []
                   +--ro error-type       enumeration
                   +--ro error-tag        string
                   +--ro error-app-tag?   string
                   +--ro error-path?      instance-identifier
                   +--ro error-message?   string
                   +--ro error-info?      <anydata>

   The following are examples of a apply-configuration-updated
   notification message:













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  <notification xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
    <eventTime>2017-06-16T16:30:59.137045+09:00</eventTime>
    <intent-configuration-update xmlns="urn:ietf:params:xml:ns:yang:ietf-nmda-notifications">
      <app-tag>ds--module-a</app-tag>
      <datastore>intended</datastore>
      <datastore>operational</datastore>
      <fail-applied-object>
        <edit-id>1<edit-id>
        <operation>merge</operation>
        <target>/ietf-interfaces:interfaces-state</target>
         <value>
            <interfaces-state xmlns="http://foo.com/ietf-interfaces">
                 <interface>
                   <name>eth0</name>
                   <oper-status>down</oper-status>
                 </interface>
            </interfaces-state>
         </value>
      </fail-applied-object>
      <fail-applied-object>
        <edit-id>2<edit-id>
        <target>/ietf-system:system</target>
        <errors>
         <error-type>protocol</error-type>
         <error-tag>mis-resource</error-tag>
         <error-path xmlns:ops="https://example.com/ns/ietf-system">\
          \/if:interfaces-state\
          \</error-path>
         <error-message>refer to resources that are not \
         \available or otherwise not physically present.\
         \</error-message>
       </errors>
      </fail-applied-object>
   </intent-configuration-update>
  </notification>

2.3.  Relation with NMDA Datastore Compare

   NMDA datastore compare [I-D.ietf-netmod-nmda-diff] could be used to
   check which part of configuration data is applied or which part of
   configuration data is not applied,e.g.,If a client creates an
   interface "et-0/0/0" but the interface does not physically exist at
   this point, the interface will appear in <intended> but does not does
   not exist in the <operational>.  By comparing configuration
   difference between <intended> and <operational>, the interface that
   is not applied can be sorted out.  Unlike [I-D.ietf-netmod-nmda-
   diff], the notification message only focuses on the configuration
   data that is not applied and the reason why the configuration changes



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   were not applied.  Also system internal interactions with hardware is
   needed within the server to make sure fail applied object is caused
   by mis-resource or remnant Configuration, etc.

2.4.  Definitions

   This section presents the YANG module defined in this document.  This
   module imports data types from the 'ietf-datastores' module defined
   in [RFC8342] and 'ietf-inet-types' module defined in [RFC6021].

 <CODE BEGINS> file "ietf-nmda-notifications@2019-06-19.yang"
module ietf-nmda-notifications {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-nmda-notifications";
  prefix ndn;
  import ietf-datastores {
    prefix ds;
  }
  import ietf-inet-types { prefix inet; }
  import ietf-yang-types { prefix yang;}
  import ietf-yang-patch {
    prefix ypatch;
  }
  import ietf-netconf {
    prefix nc;
  }
  import ietf-restconf { prefix rc;}
  organization
    "IETF NETMOD (Network Modeling) Working Group";
  contact
    "WG Web:   <http://tools.ietf.org/wg/netmod/>
     WG List:  <mailto:netmod@ietf.org>

     Editor:   Qin Wu
               <mailto:bill.wu@huawei.com>
     Editor:   Rohit R Ranade
               <mailto:rohitrranade@huawei.com>";
  description
    "This module defines a YANG data model for use with the
     NETCONF and RESTCONF protocol that allows the client to
     receive additional common event notifications related to NMDA.

     Copyright (c) 2012 IETF Trust and the persons identified as
     the document authors.  All rights reserved.
     Redistribution and use in source and binary forms, with or
     without modification, is permitted pursuant to, and subject
     to the license terms contained in, the Simplified BSD License
     set forth in Section 4.c of the IETF Trust's Legal Provisions



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     Relating to IETF Documents
     (http://trustee.ietf.org/license-info).
     This version of this YANG module is part of RFC xxxx; see
     the RFC itself for full legal notices.";

  revision 2019-06-19 {
    description
      "Initial version.";
    reference "RFC xxx: NETCONF Base Notifications for NMDA";
  }
  typedef session-id-or-zero-type {
     type uint32;
     description
       "NETCONF Session Id or Zero to indicate none";
   }
  feature error-info {
      description
        "This feature must
         also be enabled for that session if error-info
        can be advertised by the server.  Otherwise,
         this feature must not be enabled.";
    }
  grouping common-session-parms {
    description
      "Common session parameters to identify a
       management session or internal interaction
       on a set of configuration data.";

    leaf username {
      type string;
      description
        "Name of the user for the session.";
    }
    leaf source-host {
      type inet:ip-address;
      description
        "Address of the remote host for the session.";
    }

    leaf session-id {
      type session-id-or-zero-type;
      description
        "Identifier of the session.
         A NETCONF session MUST be identified by a non-zero value.
         A non-NETCONF session MAY be identified by the value zero.";
    }
    leaf app-tag {
      type string;



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      description
        "The application tag used to identify the managment session
       or internal interaction on a set of configuration data.";
    }

  }

    notification intent-configuration-updated {
      description
        "Generated when a server detects that a
         intended configuration applied event has occurred. Indicates
         the event and the current state of the intended data applying
          procedure in progress.";
      reference "RFC 8342, Section 5";
      uses common-session-parms;
      leaf src-ds {
          type identityref {
            base ds:datastore;
          }
           description
            "Indicates which datastore is
             source of edit-data operation.";
        }
      leaf dst-ds {
          type identityref {
            base ds:datastore;
          }
           description
            "Indicates which datastore is
             target of edit-data operation.";
        }
        choice filter-spec {
           description
             "The content filter specification for this request.";
           anydata subtree-filter {
             description
               "This parameter identifies the portions of the
                target datastore to retrieve.";
             reference
               "RFC 6241: Network Configuration Protocol, Section 6.";
           }
           leaf xpath-filter {
             if-feature nc:xpath;
             type yang:xpath1.0;
             description
               "This parameter contains an XPath expression identifying
                the portions of the target datastore to retrieve.




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                If the expression returns a node-set, all nodes in the
                node-set are selected by the filter.  Otherwise, if the
                expression does not return a node-set, then the get-data
                operation fails.

                The expression is evaluated in the following XPath
                context:

                  o  The set of namespace declarations are those in
                     scope on the 'xpath-filter' leaf element.

                  o  The set of variable bindings is empty.

                  o  The function library is the core function library,
                     and the XPath functions defined in section 10 in
                     RFC 7950.

                  o  The context node is the root node of the target
                     datastore.";
           }
         }
      leaf apply-result {
        type enumeration {
          enum "partial-fail" {
            description
              "A set of configuration data is not applied.";
          }
         enum "fail" {
             description
             " None of configuration data is applied.";
         }
         enum "sucess" {
             description
             " All configuration data is applied.";
         }
       }
     description
      "Configuration data apply result.";
    }
      list fail-applied-object {
        when "../apply-result = 'partial-fail'";
        key edit-id;
        ordered-by user;
        leaf edit-id {
               type string;
                description
                  "Response status is for the 'edit' list entry
                   with this 'edit-id' value.";



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             }
        leaf operation {
             type enumeration {
               enum create {
                 description
                   "The target data node is created using the supplied
                    value, only if it does not already exist.  The
                    'target' leaf identifies the data node to be
                    created, not the parent data node.";
               }
               enum delete {
                 description
                   "Delete the target node, only if the data resource
                    currently exists; otherwise, return an error.";
               }

               enum insert {
                 description
                   "Insert the supplied value into a user-ordered
                    list or leaf-list entry.  The target node must
                    represent a new data resource.  If the 'where'
                    parameter is set to 'before' or 'after', then
                    the 'point' parameter identifies the insertion
                    point for the target node.";
               }
               enum merge {
                 description
                   "The supplied value is merged with the target data
                    node.";
               }
               enum move {
                 description
                   "Move the target node.  Reorder a user-ordered
                    list or leaf-list.  The target node must represent
                    an existing data resource.  If the 'where' parameter
                    is set to 'before' or 'after', then the 'point'
                    parameter identifies the insertion point to move
                    the target node.";
               }
               enum replace {
                 description
                   "The supplied value is used to replace the target
                    data node.";
               }
               enum remove {
                 description
                   "Delete the target node if it currently exists.";
               }



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             }
             mandatory true;
             description
               "The datastore operation requested for the associated
                'edit' entry.";
           }
        leaf target {
          type ypatch:target-resource-offset;
          description
            "Topmost node associated with the configuration change.
             A server SHOULD set this object to the node within
             the datastore that is being altered.  A server MAY
             set this object to one of the ancestors of the actual
             node that was changed, or omit this object, if the
             exact node is not known.";
        }
    anydata value {
             description
               "Value used for this edit operation.  The anydata 'value'
                contains the target resource associated with the
                'target' leaf.

                For example, suppose the target node is a YANG container
                named foo:

                    container foo {
                      leaf a { type string; }
                      leaf b { type int32; }
                    }

                The 'value' node contains one instance of foo:

                    <value>
                       <foo xmlns='example-foo-namespace'>
                          <a>some value</a>
                          <b>42</b>
                       </foo>
                    </value>
                ";
        }
        uses rc:errors {if-feature error-info;}
        description
          "List for fail applied objects that is not applied. ";
      }
    }
  }
 <CODE ENDS>




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3.  Security Considerations

   The YANG module defined in this memo is designed to be accessed via
   the NETCONF protocol [RFC6241].  The lowest NETCONF layer is the
   secure transport layer and the mandatory-to-implement secure
   transport is SSH, defined in [RFC6242].

   Some of the readable data nodes in this YANG module may be considered
   sensitive or vulnerable in some network environments.  It is thus
   important to control read access (e.g., via get, get-config, or
   notification) to these data nodes.  These are the subtrees and data
   nodes and their sensitivity/vulnerability:

   /intent-configuration-update:

      Event type itself indicates that intent based configuration has
      been updated.  This event could alert an attacker that a datastore
      may have been altered.

   /intent-configuration-updated/apply-result:

      Indicates the specific intent based configuration update event
      state change that occurred.  A value of 'success' probably
      indicates that intent based configuration has been applied
      successfully.

4.  IANA Considerations

   This document registers one XML namespace URN in the 'IETF XML
   registry', following the format defined in [RFC3688]:

      URI: urn:ietf:params:xml:ns:yang:ietf-nmda-notifications

      Registrant Contact: The IESG.

      XML: N/A, the requested URI is an XML namespace.

   This document registers one module name in the 'YANG Module Names'
   registry, defined in [RFC7950]:

      name: ietf-nmda-notifications

      prefix: ndn

      namespace: urn:ietf:params:xml:ns:yang:ietf-nmda-notifications

      RFC: xxxx




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5.  Acknowledgements

   Thanks to Juergen Schoenwaelder, Alex Clemm,Carey Timothy and Andy
   Berman, Sterne Jason to review this draft and Thank Xiaojian Ding
   provide important input to the initial version of this document.

6.  Contributors

      Chong Feng
      Huawei
      Email:frank.fengchong@huawei.com

7.  Normative References

   [I-D.ietf-netmod-nmda-diff]
              Clemm, A., Qu, Y., Tantsura, J., and A. Bierman,
              "Comparison of NMDA datastores", draft-ietf-netmod-nmda-
              diff-01 (work in progress), May 2019.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              DOI 10.17487/RFC3688, January 2004,
              <https://www.rfc-editor.org/info/rfc3688>.

   [RFC5277]  Chisholm, S. and H. Trevino, "NETCONF Event
              Notifications", RFC 5277, DOI 10.17487/RFC5277, July 2008,
              <https://www.rfc-editor.org/info/rfc5277>.

   [RFC6020]  Bjorklund, M., Ed., "YANG - A Data Modeling Language for
              the Network Configuration Protocol (NETCONF)", RFC 6020,
              DOI 10.17487/RFC6020, October 2010,
              <https://www.rfc-editor.org/info/rfc6020>.

   [RFC6021]  Schoenwaelder, J., Ed., "Common YANG Data Types",
              RFC 6021, DOI 10.17487/RFC6021, October 2010,
              <https://www.rfc-editor.org/info/rfc6021>.

   [RFC6241]  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
              and A. Bierman, Ed., "Network Configuration Protocol
              (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
              <https://www.rfc-editor.org/info/rfc6241>.






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   [RFC6242]  Wasserman, M., "Using the NETCONF Protocol over Secure
              Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
              <https://www.rfc-editor.org/info/rfc6242>.

   [RFC6470]  Bierman, A., "Network Configuration Protocol (NETCONF)
              Base Notifications", RFC 6470, DOI 10.17487/RFC6470,
              February 2012, <https://www.rfc-editor.org/info/rfc6470>.

   [RFC8072]  Bierman, A., Bjorklund, M., and K. Watsen, "YANG Patch
              Media Type", RFC 8072, DOI 10.17487/RFC8072, February
              2017, <https://www.rfc-editor.org/info/rfc8072>.

   [RFC8342]  Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
              and R. Wilton, "Network Management Datastore Architecture
              (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
              <https://www.rfc-editor.org/info/rfc8342>.

Appendix A.  Changes between revisions

   v01 - v03

   o  Change notification name into intent-configuration update.

   o  Change title into NMDA Base event for intent based configuration
      update.

   o  Clarify the usage of NMDA base event and relation with NMDA diff
      work.

   v01 - v00

   o  Add application tag support and use additional parameters to
      identify management session.

   o  Remove apply-intended-start and apply-intended-end two
      notifications since they are not needed based on discussion.

Authors' Addresses

   Qin Wu
   Huawei
   101 Software Avenue, Yuhua District
   Nanjing, Jiangsu  210012
   China

   Email: bill.wu@huawei.com





Wu, et al.              Expires December 31, 2019              [Page 15]


Internet-Draft           NMDA Base Notification                June 2019


   Ran Tao
   Huawei

   Email: taoran20@huawei.com


   Rohit R Ranade
   Huawei
   Divyashree Techno Park, Whitefield
   Bangalore, Karnataka  560066
   India

   Email: rohitrranade@huawei.com






































Wu, et al.              Expires December 31, 2019              [Page 16]


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