Network Working Group M. Bjorklund
Internet-Draft Tail-f Systems
Updates: 8040 (if approved) J. Schoenwaelder
Intended status: Standards Track Jacobs University
Expires: April 12, 2019 P. Shafer
K. Watsen
Juniper Networks
R. Wilton
Cisco Systems
October 9, 2018
RESTCONF Extensions to Support the Network Management Datastore
Architecture
draft-ietf-netconf-nmda-restconf-05
Abstract
This document extends the RESTCONF protocol defined in RFC 8040 in
order to support the Network Management Datastore Architecture
defined in RFC 8342.
This document updates RFC 8040 by introducing new datastore
resources, adding a new query parameter, and requiring the usage of
I-D.ietf-netconf-rfc7895bis by RESTCONF servers implementing the
Network Management Datastore Architecture.
RFC Ed.: Please replace "I-D.ietf-netconf-rfc7895bis" above with its
final RFC assignment and remove this note.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on April 12, 2019.
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Copyright Notice
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document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Datastore and YANG Library Requirements . . . . . . . . . . . 3
3. RESTCONF Extensions . . . . . . . . . . . . . . . . . . . . . 3
3.1. New Datastore Resources . . . . . . . . . . . . . . . . . 3
3.2. Protocol Operations . . . . . . . . . . . . . . . . . . . 4
3.2.1. With-defaults query parameter on the operational
state datastore . . . . . . . . . . . . . . . . . . . 5
3.2.2. New "with-origin" Query Parameter . . . . . . . . . . 5
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
5. Security Considerations . . . . . . . . . . . . . . . . . . . 6
6. Normative References . . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
This document extends the RESTCONF protocol defined in [RFC8040] in
order to support the Network Management Datastore Architecture (NMDA)
defined in [RFC8342].
This document updates [RFC8040] in order to enable RESTCONF clients
to discover which datastores are supported by the RESTCONF server,
determine which modules are supported in each datastore, and to
interact with all the datastores supported by the NMDA.
Specifically, the update introduces new datastore resources, adds a
new query parameter, and requires the usage of
[I-D.ietf-netconf-rfc7895bis] by RESTCONF servers implementing the
NMDA.
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The solution presented in this document is backwards compatible with
[RFC8040]. This is achieved by only adding new resources and leaving
the semantics of the existing resources unchanged.
1.1. Terminology
This document uses the terminology defined by the NMDA [RFC8342].
The keywords "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.
2. Datastore and YANG Library Requirements
RFC Ed.: Please update 201X-XX-XX below with correct date and remove
this note.
An NMDA-compliant RESTCONF server MUST support the operational state
datastore and it MUST implement at least revision 201X-XX-XX of the
"ietf-yang-library" module defined in [I-D.ietf-netconf-rfc7895bis].
Such a server identifies that it supports the NMDA both by
implementing the {+restconf}/ds/ietf-datastores:operational resource,
and by implementing at least revision 201X-XX-XX of the
"ietf-yang-library" module.
A RESTCONF client can test if a server supports the NMDA by using
either the HEAD or GET methods on {+restconf}/ds/ietf-
datastores:operational.
A RESTCONF client can discover which datastores and YANG modules the
server supports by reading the YANG library information from the
operational state datastore.
3. RESTCONF Extensions
This section describes the RESTCONF extensions needed to support the
NMDA.
3.1. New Datastore Resources
This document defines a set of new resources representing datastores
as defined in [RFC8342]. These resources are available using the
following resource path template:
{+restconf}/ds/<datastore>
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The <datastore> path component is encoded as an "identityref"
according to the JSON encoding rules for identities, defined in
Section 6.8 of [RFC7951]. The namespace-qualified form MUST be used.
Such an identity MUST be derived from the "datastore" identity
defined in the "ietf-datastores" YANG module [RFC8342].
Specifically:
o The resource {+restconf}/ds/ietf-datastores:operational refers to
the operational state datastore.
o The resource {+restconf}/ds/ietf-datastores:running refers to the
running configuration datastore.
o The resource {+restconf}/ds/ietf-datastores:intended refers to the
intended configuration datastore.
An NMDA-compliant server MUST implement {+restconf}/ds/ietf-
datastores:operational. Other datastore resources MAY be
implemented.
YANG actions can only be invoked in {+restconf}/ds/ietf-
datastores:operational.
If a server implements other datastores, such as the example
datastore "ds-ephemeral" in the module "example-ds-ephemeral", the
server would implement the resource {+restconf}/ds/example- ds-
ephemeral:ds-ephemeral.
3.2. Protocol Operations
The protocol operations available for the new datastore resources
(Section 3.1) are the same as the protocol operations defined in
[RFC8040] for the {+restconf}/data resource with the following
exceptions:
o Dynamic configuration datastores are excluded, as each dynamic
configuration datastore definition needs to be reviewed for what
protocol operations it supports.
o Some datastores are read-only by nature (e.g., <intended>), and
hence any attempt to modify these datastores will fail. A server
MUST return a response with a "405 Method Not Allowed" status-line
and error-tag value "operation-not-supported".
o The semantics of the "with-defaults" query parameter ([RFC8040],
Section 4.8.9) differs when interacting with the operational state
datastore. The semantics are described below, in Section 3.2.1.
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o [RFC8040], Section 3.5.4, paragraph 3 does not apply when
interacting with any resource under {+restconf}/ds.
3.2.1. With-defaults query parameter on the operational state datastore
The "with-defaults" query parameter ([RFC8040], Section 4.8.9) is
OPTIONAL to support when interacting with {+restconf}/ds/ietf-
datastores:operational. The associated capability to indicate a
server's support is identified with the URI:
urn:ietf:params:restconf:capability:with-operational-defaults:1.0
For servers that support it, the behavior of the "with-defaults"
query parameter on the operational state datastore is defined as
follows:
o If no "with-defaults" query parameter is specified, or if it is
set to "explicit", "report-all", or "report-all-tagged", then the
"in use" values, as defined in [RFC8342] section 5.3, are returned
from the operational state datastore, even if a node happens to
have a default statement in the YANG module and this default value
is being used by the server. If the "with-defaults" parameter is
set to "report-all-tagged", any values that match the schema
default are tagged with additional metadata, as described in
[RFC8040], Section 4.8.9.
o If the "with-defaults" query parameter is set to "trim", all "in
use" values are returned, except that the output is filtered to
exclude any values that match the default defined in the YANG
schema.
Servers are not required to support all values in the "with-defaults"
query parameter on the operational state datastore. If a request is
made using a value that is not supported, then the error handling
behavior is as described in ([RFC8040], Section 4.8.9).
3.2.2. New "with-origin" Query Parameter
A new query parameter named "with-origin" is added to the GET
operation. If present, it requests that the server includes "origin"
metadata annotations in its response, as detailed in the NMDA. This
parameter is only valid when querying {+restconf}/ds/ietf-
datastores:operational or any datastores with identities derived from
the "operational" identity. Otherwise, if an invalid datastore is
specified then the server MUST return a response with a "400 Bad
Request" status-line, using an error-tag value of "invalid-value".
"origin" metadata annotations are not included unless a client
explicitly requests them.
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Data in the operational state datatstore can come from multiple
sources. The server should return the most accurate value for the
"origin" metadata annotation as possible, indicating the source of
the operational value, as specified in Section 5.3.4 of [RFC8342].
When encoding the origin metadata annotation for a hierarchy of
returned nodes, the annotation can be omitted for a child node when
the value matches that of the parent node, as described in
"ietf-origin" YANG module [RFC8342].
The "with-origin" query parameter is OPTIONAL to support. It is
identified with the URI:
urn:ietf:params:restconf:capability:with-origin:1.0
4. IANA Considerations
This document defines two capability identifier URNs in the "RESTCONF
Capability URNs" registry defined in [RFC8040]:
Index
Capability Identifier
---------------------
:with-origin
urn:ietf:params:restconf:capability:with-origin:1.0
:with-operational-defaults
urn:ietf:params:restconf:capability:with-operational-defaults:1.0
5. Security Considerations
This document extends the RESTCONF protocol by introducing new
datastore resources. The lowest RESTCONF layer is HTTPS, and the
mandatory-to-implement secure transport is TLS [RFC8446]. The
RESTCONF protocol uses the network configuration access control model
[RFC8341], which provides the means to restrict access for particular
RESTCONF users to a preconfigured subset of all available RESTCONF
protocol operations and content.
The security constraints for the base RESTCONF protocol (see
Section 12 of [RFC8040]) apply to the new RESTCONF datastore
resources defined in this document.
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6. Normative References
[I-D.ietf-netconf-rfc7895bis]
Bierman, A., Bjorklund, M., Schoenwaelder, J., Watsen, K.,
and R. Wilton, "YANG Library", draft-ietf-netconf-
rfc7895bis-06 (work in progress), April 2018.
[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>.
[RFC7951] Lhotka, L., "JSON Encoding of Data Modeled with YANG",
RFC 7951, DOI 10.17487/RFC7951, August 2016,
<https://www.rfc-editor.org/info/rfc7951>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/info/rfc8040>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration
Access Control Model", STD 91, RFC 8341,
DOI 10.17487/RFC8341, March 2018, <https://www.rfc-
editor.org/info/rfc8341>.
[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>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
Authors' Addresses
Martin Bjorklund
Tail-f Systems
Email: mbj@tail-f.com
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Juergen Schoenwaelder
Jacobs University
Email: j.schoenwaelder@jacobs-university.de
Phil Shafer
Juniper Networks
Email: phil@juniper.net
Kent Watsen
Juniper Networks
Email: kwatsen@juniper.net
Robert Wilton
Cisco Systems
Email: rwilton@cisco.com
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