| 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
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.
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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.
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.
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.
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.
This section describes the RESTCONF extensions needed to support the NMDA.
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>
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:
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.
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:
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:
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).
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.
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
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
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.
| [I-D.ietf-netconf-rfc7895bis] | Bierman, A., Bjorklund, M., Schoenwaelder, J., Watsen, K. and R. Wilton, "YANG Library", Internet-Draft draft-ietf-netconf-rfc7895bis-06, 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. |
| [RFC7951] | Lhotka, L., "JSON Encoding of Data Modeled with YANG", RFC 7951, DOI 10.17487/RFC7951, August 2016. |
| [RFC8040] | Bierman, A., Bjorklund, M. and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017. |
| [RFC8174] | Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017. |
| [RFC8341] | Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, March 2018. |
| [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. |
| [RFC8446] | Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018. |