RESTCONF Extension to Support Trace Context Headers
draft-ietf-netconf-restconf-trace-ctx-headers-03
The information below is for an old version of the document.
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| Authors | Roque Gagliano , Kristian Larsson , Jan Lindblad | ||
| Last updated | 2024-11-08 (Latest revision 2024-09-25) | ||
| Replaces | draft-netconf-restconf-trace-ctx-headers | ||
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draft-ietf-netconf-restconf-trace-ctx-headers-03
NETCONF R. Gagliano
Internet-Draft Cisco Systems
Intended status: Standards Track K. Larsson
Expires: 11 May 2025 Deutsche Telekom AG
J. Lindblad
Cisco Systems
7 November 2024
RESTCONF Extension to Support Trace Context Headers
draft-ietf-netconf-restconf-trace-ctx-headers-03
Abstract
This document defines an extension to the RESTCONF protocol in order
to support Trace Context propagation as defined by the W3C.
About This Document
This note is to be removed before publishing as an RFC.
The latest revision of this draft can be found at https://github.com/
netconf-wg/restconf-trace-ctx-headers/blob/gh-pages/draft-ietf-
netconf-restconf-trace-ctx-headers.txt. Status information for this
document may be found at https://datatracker.ietf.org/doc/draft-ietf-
netconf-restconf-trace-ctx-headers/.
Discussion of this document takes place on the NETCONF Working Group
mailing list (mailto:netconf@ietf.org), which is archived at
https://mailarchive.ietf.org/arch/browse/netconf/. Subscribe at
https://www.ietf.org/mailman/listinfo/netconf/.
Source for this draft and an issue tracker can be found at
https://github.com/https://github.com/netconf-wg/restconf-trace-ctx-
headers.
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/.
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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 11 May 2025.
Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved.
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
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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. RESTCONF Extensions . . . . . . . . . . . . . . . . . . . . . 3
2.1. Error Handling . . . . . . . . . . . . . . . . . . . . . 4
2.2. Trace Context Header Versioning . . . . . . . . . . . . . 4
3. Security Considerations . . . . . . . . . . . . . . . . . . . 4
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
5. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 5
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
6.1. Normative References . . . . . . . . . . . . . . . . . . 5
6.2. Informative References . . . . . . . . . . . . . . . . . 6
Appendix A. Example RESTCONF Calls . . . . . . . . . . . . . . . 6
A.1. Successful creation of New Data Resources (from
Appendix B.2.1 of RFC8040) . . . . . . . . . . . . . . . 6
A.2. Unsuccessful creation of New Data Resources (from
Appendix B.2.1 of RFC8040) . . . . . . . . . . . . . . . 7
Appendix B. Changes (to be deleted by RFC Editor) . . . . . . . 9
B.1. From version 01 to 02 . . . . . . . . . . . . . . . . . . 9
B.2. From version 00 to -01 . . . . . . . . . . . . . . . . . 9
B.3. From version 00 to
draft-ietf-netconf-restconf-trace-ctx-headers-00 . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
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1. Introduction
Network automation and management systems commonly consist of
multiple sub-systems and, together with the network devices they
manage, they effectively form a distributed system. Distributed
tracing is a methodology implemented by tracing tools to track,
analyze and debug operations such as configuration transactions,
across multiple distributed systems.
The W3C has defined two HTTP headers (traceparent and tracestate) in
[W3C-Trace-Context] for context propagation that are useful for
distributed systems like the ones defined in section 4 of [RFC8309].
According to the W3C specification, each operation is uniquely
identified by a "trace-id" field, and carries multiple metadata
fields about the operation. Propagating this Trace Context between
systems provides a coherent view of the entire operation as carried
out by all involved systems.
In [I-D.draft-ietf-netconf-trace-ctx-extension], the NETCONF protocol
extension is defined and we will re-use several of the YANG and XML
objects defined in that document for RESTCONF. Please refer to that
document for additional context and example applications.
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.
Additionally, the document utilizes the following abbreviations:
OTLP: OpenTelemetry protocol as defined by [OpenTelemetry]
M.E.L.T: Metrics, Events, Logs and Traces
gNMI: gRPC Network Management Interface, as defined by [gNMI]
2. RESTCONF Extensions
A RESTCONF server that implements the Trace Context propagation
mechanism defined in this document MUST support the Trace Context
traceparent header as defined in [W3C-Trace-Context].
A RESTCONF server SHOULD support the Trace Context tracestate header
as defined in [W3C-Trace-Context].
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2.1. Error Handling
A RESTCONF server SHOULD follow the "Processing Model for Working
with Trace Context" as specified in [W3C-Trace-Context]. Based on
this processing model, it is NOT RECOMMENDED to reject an RPC because
of the Trace Context header values.
If a server decides to reject an RPC because of the Trace Context
header values, the server MUST return a RESTCONF rpc-error with the
following values:
error-tag: operation-failed
error-type: protocol
error-severity: error
Additionally, the error-info tag SHOULD contain a relevant details
about the error.
Finally, the sx:structure defined in
[I-D.draft-ietf-netconf-trace-ctx-extension] SHOULD be present in any
error message from the server.
2.2. Trace Context Header Versioning
The RESTCONF protocol extension described in this document refers to
the [W3C-Trace-Context] Trace Context capability. The W3C
traceparent and tracestate headers include the notion of versions.
It would be desirable for a RESTCONF client to be able to discover
the one or multiple versions of these headers supported by a server.
[I-D.draft-ietf-netconf-trace-ctx-extension] defines a pair YANG
modules that SHOULD be included in the YANG library per [RFC8525] of
the RESTCONF server supporting the RESTCONF Trace Context extension
that will refer to the headers' supported versions. Future updates
of this document could include additional YANG modules for new
headers' versions.
3. Security Considerations
The related document [I-D.draft-ietf-netconf-trace-ctx-extension]
defines two YANG modules that are used when implementing the Trace
Context concept, regardless of YANG-based protocol. These modules
are completely empty, and therefore have very limited security
considerations. Their purpose is only to indicate which Trace
Context header versions the server supports using YANG Library
[RFC8525].
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The traceparent and tracestate headers make it easier to track and
correlate the flow of requests and their downstream effect on other
systems. This is indeed the whole point with these headers. This
knowledge may be used by unauthorized entities to infer a map of a
managed network.
All advice mentioned in the [W3C-Trace-Context] under the Privacy
Considerations and Security Considerations also apply to this
document.
The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement
secure transport is TLS [RFC8446].
4. IANA Considerations
This document has no IANA actions.
5. Acknowledgments
The authors would like to acknowledge the valuable implementation
feedback from Christian Rennerskog and Per Andersson. Many thanks to
Raul Rivas Felix, Alexander Stoklasa, Luca Relandini and Erwin
Vrolijk for their help with the demos regarding integrations. The
help and support from Med Boucadair, Jean Quilbeuf and Benoît Claise
has also been invaluable to this work.
6. References
6.1. Normative References
[gNMI] "gNMI - gRPC Network Management Interface", 4 November
2024, <https://github.com/openconfig/gnmi>.
[I-D.draft-ietf-netconf-trace-ctx-extension]
Gagliano, R., Larsson, K., and J. Lindblad, "NETCONF
Extension to support Trace Context propagation", Work in
Progress, Internet-Draft, draft-ietf-netconf-trace-ctx-
extension-02, 7 November 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
trace-ctx-extension-02>.
[OpenTelemetry]
"OpenTelemetry Cloud Native Computing Foundation project",
4 November 2024, <https://opentelemetry.io>.
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[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/rfc/rfc2119>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/rfc/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/rfc/rfc8174>.
[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/rfc/rfc8446>.
[RFC8525] Bierman, A., Bjorklund, M., Schoenwaelder, J., Watsen, K.,
and R. Wilton, "YANG Library", RFC 8525,
DOI 10.17487/RFC8525, March 2019,
<https://www.rfc-editor.org/rfc/rfc8525>.
[W3C-Trace-Context]
"W3C Recommendation on Trace Context", 23 November 2021,
<https://www.w3.org/TR/2021/REC-trace-context-
1-20211123/>.
6.2. Informative References
[RFC8309] Wu, Q., Liu, W., and A. Farrel, "Service Models
Explained", RFC 8309, DOI 10.17487/RFC8309, January 2018,
<https://www.rfc-editor.org/rfc/rfc8309>.
Appendix A. Example RESTCONF Calls
All examples from Appendix B of [RFC8040] could be recreated in this
section by adding the new header described in this document. We
selected one example from that document as reference.
A.1. Successful creation of New Data Resources (from Appendix B.2.1 of
[RFC8040])
To create a new "artist" resource within the "library" resource, a
client might send the following request:
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POST /restconf/data/example-jukebox:jukebox/library HTTP/1.1
Host: example.com
Content-Type: application/yang-data+json
traceparent: 00-405062f633be64ee006089dfca95a153-e021f9e263aad8e2-01
tracestate: vendorname1=opaqueValue1,vendorname2=opaqueValue2
{
"example-jukebox:artist" : [
{
"name" : "Foo Fighters"
}
]
}
If the resource is created, the server might respond as follows:
HTTP/1.1 201 Created
Date: Thu, 26 Jan 2017 20:56:30 GMT
Server: example-server
Location: https://example.com/restconf/data/\
example-jukebox:jukebox/library/artist=Foo%20Fighters
Last-Modified: Thu, 26 Jan 2017 20:56:30 GMT
ETag: "b3830f23a4c"
traceparent: 00-405062f633be64ee006089dfca95a153-e021f9e263aad8e2-01
tracestate: vendorname1=opaqueValue1,vendorname2=opaqueValue2
A.2. Unsuccessful creation of New Data Resources (from Appendix B.2.1
of [RFC8040])
[W3C-Trace-Context] specifies that a vendor may validate the
tracestate header and that invalid headers may be discarded.
Section 2.1 on Error handling (Section 2.1), states that servers may
return an error. Let's assume that an implementation follows that
behavior.
Example of a badly formated tracestate header using [RFC8040] example
(Appendix B.2.1), in which a server receives the following:
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POST /restconf/data/example-jukebox:jukebox/library HTTP/1.1
Host: example.com
Content-Type: application/yang-data+json
traceparent: 00-405062f633be64ee006089dfca95a153-e021f9e263aad8e2-01
tracestate: SomeBadFormatHere
{
"example-jukebox:artist" : [
{
"name" : "Foo Fighters"
}
]
}
To which the server responds with an error message:
HTTP/1.1 400 Bad Request
Date: Thu, 20 Jun 2024 20:56:30 GMT
Server: example-server
Content-Type: application/yang-data+json
{ "ietf-restconf:errors" : {
"error" : [
"trace-context-error-info": {
{
"error-type" : "protocol",
"error-tag" : "operation-failed",
"error-severity" : "error",
"error-message" :
"Context traceparent header incorrectly formatted",
"error-info": {
"ietf-trace-context:meta-name" : "tracestate",
"ietf-trace-context:meta-value" :
"SomeBadFormatHere",
"ietf-trace-context:error-type" :
"ietf-trace-context:bad-format"
}
}
}
]
}
}
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Appendix B. Changes (to be deleted by RFC Editor)
B.1. From version 01 to 02
* Added WGLC comments
* Changed namespaces and module name
* Fix error in error response
* Comments from Med Boucadair
* Removed markdown formatting of tracestate and traceparent, as
toolchain could not handle this properly
* Removed references to RFC8341 (NACM) as the passage in the
security considerations no longer need it
* Rearranged text in introduction to include referenes in a more
natural order
* Removed several references to "we" and replaced with more neutral
language
* Clarified that everything described as MUST requirements in this
document only apply to RESTCONF implementations that implement
this document. Other RESTCONF implementations do not need to care
about this document, it's an optional extension
* Clarified that the YANG modules used by this document is defined
by the sibling document for NETCONF
* Lots of updated wording based on review feedback
B.2. From version 00 to -01
* Added Security considerations
* Added Acknowledgements
* Added several Normative references
* Added links to latest document on github
* Added RESTCONF example for success and error
* Modified Error Handling to reflect better W3C alignment based on
implementation feedback
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* Firmed up error handling and YANG-library to MUST-requirements
B.3. From version 00 to draft-ietf-netconf-restconf-trace-ctx-
headers-00
* Adopted by NETCONF WG
* Moved repository to NETCONF WG
* Changed build system to use martinthomson's excellent framework
* Ran make fix-lint to remove white space at EOL etc.
* Added this change note. No other content changes
Authors' Addresses
Roque Gagliano
Cisco Systems
Avenue des Uttins 5
CH-1180 Rolle
Switzerland
Email: rogaglia@cisco.com
Kristian Larsson
Deutsche Telekom AG
Email: kll@dev.terastrm.net
Jan Lindblad
Cisco Systems
Email: jlindbla@cisco.com
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