NETMOD Q. Ma, Ed.
Internet-Draft C. Feng
Updates: RFC6241, RFC8040, RFC8342 (if approved) Q. Wu
Intended status: Standards Track Huawei
Expires: 28 April 2022 25 October 2021
System-defined Configuration
draft-ma-netmod-with-system-00
Abstract
This document updates NMDA [RFC 8342] to define a read-only
conventional configuration datastore called "system" to hold system-
defined configurations. To support non-NMDA servers, a "with-system"
parameter has been defined to return <running> and system-defined
configuration combined. The solution enables clients to reference
nodes defined in <system>, overwrite values of configurations defined
in <system>, and configure descendant nodes of system-defined nodes.
Status of This Memo
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This Internet-Draft will expire on 28 April 2022.
Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
1.2. Requirements Language . . . . . . . . . . . . . . . . . . 4
1.3. Updates to RFC 6241 . . . . . . . . . . . . . . . . . . . 4
1.4. Updates to RFC 8040 . . . . . . . . . . . . . . . . . . . 5
2. Kinds of System Configuration . . . . . . . . . . . . . . . . 5
2.1. Immediately-Active . . . . . . . . . . . . . . . . . . . 5
2.2. Conditionally-Active . . . . . . . . . . . . . . . . . . 6
2.3. Inactive-Until-Referenced . . . . . . . . . . . . . . . . 6
3. Static Characteristics . . . . . . . . . . . . . . . . . . . 6
3.1. Read-only to Clients . . . . . . . . . . . . . . . . . . 6
3.2. May Change via Software Upgrades . . . . . . . . . . . . 6
3.3. No Impact to <operational> . . . . . . . . . . . . . . . 7
4. Dynamic Behavior . . . . . . . . . . . . . . . . . . . . . . 7
4.1. Conceptual Model . . . . . . . . . . . . . . . . . . . . 7
4.2. Modifying (overriding) system configuration . . . . . . . 8
4.3. Explicit declaration of system configuration . . . . . . 8
4.4. Examples . . . . . . . . . . . . . . . . . . . . . . . . 9
4.4.1. Modifying A System-instantiated Leaf's Value . . . . 9
4.4.2. Configuring Descendant Nodes of A System-defined
Node . . . . . . . . . . . . . . . . . . . . . . . . 11
4.4.3. Declaring A System-defined Node in <running>
Explicitly . . . . . . . . . . . . . . . . . . . . . 13
5. Discovering System Configuration . . . . . . . . . . . . . . 13
5.1. The "with-system" Query Parameter . . . . . . . . . . . . 14
5.2. The <system> Configuration Datastore . . . . . . . . . . 14
6. The "ietf-netconf-with-system" Module . . . . . . . . . . . . 15
6.1. Data Model Overview . . . . . . . . . . . . . . . . . . . 15
6.2. Example Usage . . . . . . . . . . . . . . . . . . . . . . 16
6.3. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 17
7. The "ietf-system-datastore" Module . . . . . . . . . . . . . 19
7.1. Data Model Overview . . . . . . . . . . . . . . . . . . . 19
7.2. Example Usage . . . . . . . . . . . . . . . . . . . . . . 20
7.3. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 20
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
8.1. The "IETF XML" Registry . . . . . . . . . . . . . . . . . 21
8.2. The "YANG Module Names" Registry . . . . . . . . . . . . 22
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9. Security Considerations . . . . . . . . . . . . . . . . . . . 22
9.1. Regarding the "ietf-netconf-with-system" YANG Module . . 22
9.2. Regarding the "ietf-system-datastore" YANG Module . . . . 23
10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 23
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 23
References . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Normative References . . . . . . . . . . . . . . . . . . . . . 23
Informative References . . . . . . . . . . . . . . . . . . . . 24
Appendix A. Key Use Cases . . . . . . . . . . . . . . . . . . . 24
A.1. Device Powers On . . . . . . . . . . . . . . . . . . . . 24
A.2. Client Commits Configuration . . . . . . . . . . . . . . 25
A.3. Operator Installs Card into a Chassis . . . . . . . . . . 26
Appendix B. Changes between Revisions . . . . . . . . . . . . . 27
Appendix C. Open Issues tracking . . . . . . . . . . . . . . . . 28
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 28
1. Introduction
NMDA Architecture [RFC8342] defines system configuration as the
configuration that is supplied by the device itself and should be
present in <operational> when it is in use.
However, there is a desire to enable a server to better document the
system configuration. Clients can benefit from a standard mechanism
to see what system configuration is available in a server.
In some cases, a client or offline tool may consider the
configuration in <running> or <intended> invalid due to references
(e.g. leafref) to system configuration data that isn't returned when
the datastore is read. The server may accept a configuration (i.e.
by internally merging the client specified contents of <running> with
the server-provided system configuration and validating the result),
but the client or offline tool would consider the datastore contents
as invalid.
Having to copy the entire contents of the system configuration into
<running> should be avoided or reduced when possible.
In some other cases, configuration of descendant nodes of system
defined configuration needs to be supported. For example, the system
configuration may contain an almost empty physical interface, while
the client needs to be able to add, modify, remove a number of
descendant nodes. Some descendant nodes may not be modifiable (e.g.
"name" and "type" set by the system).
In all cases, the clients should have control over the configurations
,i.e., read-back of <running> should contain only what was explicitly
set by clients.
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This document updates NMDA [RFC 8342] to define a read-only
conventional configuration datastore called "system" to hold system-
defined configurations. To support non-NMDA servers, a "with-system"
parameter has been defined to return <running> and system-defined
configuration combined. The solution enables clients to reference
nodes defined in <system>, overwrite values of configurations defined
in <system>, and configure descendant nodes of system-defined nodes.
1.1. Terminology
This document assumes that the reader is familiar with the contents
of [RFC6241], [RFC7950], [RFC8342], [RFC8407], and [RFC8525] and uses
terminologies from those documents.
The following terms are defined in this document as follows:
System configuration: Configuration that is provided by the system
itself [RFC8342].
Conventional configuration datastore: One of the following set of
configuration datastores: <running>, <startup>, <candidate>,
<system>, and <intended>. These datastores share a common
datastore schema, and protocol operations allow copying data
between these datastores. The term "conventional" is chosen as a
generic umbrella term for these datastores.
System configuration datastore: A configuration datastore holding
the complete configuration provided by the system itself. This
datastore is referred to as "<system>".
1.2. Requirements Language
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.
1.3. Updates to RFC 6241
The <get> and <get-config> RPC operations defined in [RFC6241] are
augmented to accept additional new input parameter "with-system"
which carries no value. The retrieval of implicit hidden system
configuration in <running> can be used through <get> or <get-config>
operation with the presence of "with-system" parameter.
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The implicit hidden system configuration will contain all three types
of system configurations defined in Section 2.
Note that the <get-data> RPC operation defined in [RFC8526] can also
be augmented to retrieve the system configuration from <running>.
But not sure whether the new client only supports <get-data>
operation or supports both <get-config> operation and <get-data>
operation.
1.4. Updates to RFC 8040
This document extends Section 4.8 of [RFC8040] to add a new query
parameter "with-system".
The "with-system" parameter controls whether implicitly hidden system
configuration will be returned in the reply. This parameter is only
allowed with no values carried. If this parameter has any unexpected
value, then a "400 Bad Request" status-line is returned.
+------------+---------+-----------------------------------------+
| Name | Methods | Description |
+-------------+---------+-----------------------------------------+
| with-system | GET, | indicates that the implicitly hidden |
| | HEAD | system configuration should be returned.|
| | | If not specified, then no implicitly |
| | | hidden system configuration should be |
| | | returned. This parameter can be given |
| | | in any order. |
+-------------+---------+-----------------------------------------+
2. Kinds of System Configuration
There are three types of system configurations: immediately-activated
system configuration, conditionally-activated system configuration
and inactivated-until-referenced system configuration.
2.1. Immediately-Active
Immediately-active system configurations are those applied and active
immediately (e.g., a loop-back interface) , irrespective of physical
resource present or not, a special functionality enabled or not.
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2.2. Conditionally-Active
System configurations which are provided and activated based on
specific conditions being met in a system, e.g.,if a physical
resource is present (e.g., insert interface card), the system will
automatically detect it and load pre-provisioned configuration; when
the physical resource is not present( remove interface card), the
system configuration will be automatically cleared. Another example
is when a special functionality is enabled, e.g., when QoS function
is enabled, QoS policies are automatically created by the system.
2.3. Inactive-Until-Referenced
There are some predefined objects(e.g., application ids, anti-x
signatures, trust anchor certs, etc) as a convenience for the
clients. The clients can also define their own data objects for
their unique requirements. Inactive-until-referenced system
configurations are not applied and active immediately but only after
they are referenced by client defined configuration.
3. Static Characteristics
3.1. Read-only to Clients
From the clients' perspective, the contents of the <system> datastore
are read-only. There is no way to delete system configuration from a
server. Any deletable system-provided configuration must be defined
in <factory-default> [RFC 8808], which is used to initialize
<running> when the device is first-time powered on or reset to its
factory default condition.
3.2. May Change via Software Upgrades
System configuration MAY change dynamically, e.g., depending on
factors like during device upgrade or system-controlled
resources(e.g., HW available) . In some implementations, when QoS
function is enabled, QoS-related predefined policies are created by
system. If the system configuration gets changed, YANG notification
(e.g., "push-change-update" notification)[RFC8641][RFC8639][RFC6470]
can be used to notify the client.
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3.3. No Impact to <operational>
This work intends to have no impact to <operational>. As always,
system configuration will appear in <operational> with
"origin=system". This work enables a subset of those system
generated nodes to be defined like configuration, i.e., made visible
to clients in order for being referenced or configurable prior to
present in <operational>. "Config false" nodes are completely out of
scope, hence existing "config false" nodes are not impacted by this
work.
4. Dynamic Behavior
4.1. Conceptual Model
This document introduces an optional datastore named "system" which
is used to hold all three types of system configurations defined in
Section 2.
When the device is powered on, immediately-activated system
configuration will be provided and activated immediately but
inactivated-until-referenced system configuration only becomes active
if it is referenced by client defined configuration. While
conditionally-activated system configuration will be created and
immediately activated if the condition on system resources is met
when the device is powered on or running.
All these system configuration will be implicitly hidden in the
<running>, hence the client can retrieve them through standard
operations defined in YANG-driven management protocols such as
NETCONF and RESTCONF with a "with-system" query parameter. So that
the client can get a merged view from the server.
If the <system> datastore exists, all above three types of system
configurations will also go into <system>. Then the server will
merge <running> and <system> to create <intended>, in which process,
<running> MAY overwrite and/or extend <system>. If a server
implements <intended>, <system> MUST be merged into <intended>.
When the client needs to configure the descendant nodes of system
configuration(e.g., a physical interfaces), the ancestor system
configuration needs to be configured in <running> explicitly.
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4.2. Modifying (overriding) system configuration
In some cases, a server may allow some parts of system configuration
to be modified. List keys in system configuration can't be changed
by a client, but other descendant nodes in a list entry may be
modifiable or non-modifiable. Leafs and leaf-lists outside of lists
may also be modifiable or non-modifiable. Modification of system
configuration is achieved by the client writing configuration to
<running> that overrides the system configuration. Client
configuration statements in <running> take precedence over system
configuration nodes in <system> if the server allows the nodes to be
modified. If a system configuration node is non-modifiable, then
writing a value for that node in <running> returns an error.
A server may also allow a client to add data nodes to a list entry in
<system> by writing those additional nodes in <running>. Those
additional data nodes may not exist in <system> (i.e. an *addition*
rather than an override).
While modifying (overriding) system configuration nodes may be
supported by a server, there is no mechanism for deleting a system
configuration node. A "mandatory true" leaf, for example, may have a
value in <system> which can be modified (overridden) by a client
setting that leaf to a value in <running>. But the leaf could not be
deleted.
Comment 1: What if <System> contains a set of values for a leaf-list,
and a client configures another set of values for that leaf-list in
<running>, will the set of values in <running> completely replace the
set of values in <system>? Or the two sets of values are merged
together?
Comment 2: how "ordered-by user" lists and leaf-lists are merged? Do
the <running> values go before or after, or is this a case where a
full-replace is needed.
4.3. Explicit declaration of system configuration
In addition to modifying system configuration, and adding nodes to
lists in system configuration as described above, a client can also
explicitly declare system configuration nodes in <running> with the
same values as in <system>. When a client configures a node (list
entry, leaf, etc) in <running> that matches the same node & value in
<system>, then that node becomes part of <running>. A read of
<running> returns those explicitly configured nodes.
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This explicit configuration of system configuration in <running> can
be useful, for example, when an operator's workflow requires a client
or offline tool to see the <running> configuration as valid. The
client can explicitly declare (i.e. configure in <running>) the list
entries (with at least the keys) for any system configuration list
entries that are referenced elsewhere in <running>. The client does
not necessarily need to declare all the contents of the list entry
(i.e. the descendant nodes) - only the parts that are required to
make the <running> appear valid offline.
4.4. Examples
The examples within this document use the fictional interface YANG
module defined in Appendix C.3 of [RFC8342]. In addition, a
fictional QoS data model example is provided.
4.4.1. Modifying A System-instantiated Leaf's Value
In this subsection, we will use this fictional QoS data model:
container qos-policies {
list policy {
key "name";
leaf name {
type string;
}
list queue {
key "queue-id";
description "Enter the queue list instance";
leaf queue-id {
type int32 {
range "1..32";
}
}
leaf maximum-burst-size {
type int32 {
range "0..100";
}
}
}
}
}
Suppose a client creates a qos policy "my-policy" with 4 system
instantiated queues(1~4). The Configuration of qos-policies is
present in <system> as follows:
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<qos-policies>
<name>my-policy</name>
<queue>
<queue-id>1</queue-id>
<maximum-burst-size>50</maximum-burst-size>
</queue>
<queue>
<queue-id>2</queue-id>
<maximum-burst-size>60</maximum-burst-size>
</queue>
<queue>
<queue-id>3</queue-id>
<maximum-burst-size>70</maximum-burst-size>
</queue>
<queue>
<queue-id>4</queue-id>
<maximum-burst-size>80</maximum-burst-size>
</queue>
</qos-policies>
A client modifies the value of maximum-burst-size to 55 in queue-id
1:
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<edit-config>
<target>
<running/>
</target>
<config>
<qos-policies>
<name>my-policy</name>
<queue>
<queue-id>1</queue-id>
<maximum-burst-size>55</maximum-burst-size>
</queue>
</qos-policies>
</config>
</edit-config>
</rpc>
Then the configuration of qos-policies is present in <operational> as
follows:
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<qos-policies xmlns:or="urn:ietf:params:xml:ns:yang:ietf-origin"
or:origin="or:intended">
<name>my-policy</name>
<queue>
<queue-id>1</queue-id>
<maximum-burst-size>55</maximum-burst-size>
</queue>
<queue or:origin="or:system">
<queue-id>2</queue-id>
<maximum-burst-size>60</maximum-burst-size>
</queue>
<queue or:origin="or:system">
<queue-id>3</queue-id>
<maximum-burst-size>70</maximum-burst-size>
</queue>
<queue or:origin="or:system">
<queue-id>4</queue-id>
<maximum-burst-size>80</maximum-burst-size>
</queue>
</qos-policies>
4.4.2. Configuring Descendant Nodes of A System-defined Node
Suppose the system provides a loopback interface (named "lo0") with a
default IPv4 address of "127.0.0.1" and a default IPv6 address of
"::1".
The configuration of "lo0" interface is present in <system> as
follows:
<interfaces>
<interface>
<name>lo0</name>
<ip-address>127.0.0.1</ip-address>
<ip-address>::1</ip-address>
</interface>
</interfaces>
The configuration of "lo0" interface is present in <operational> as
follows:
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<interfaces xmlns:or="urn:ietf:params:xml:ns:yang:ietf-origin"
or:origin="or:system">
<interface>
<name>lo0</name>
<ip-address>127.0.0.1</ip-address>
<ip-address>::1</ip-address>
</interface>
</interfaces>
Later on, the client further configures the description node of a
"lo0" interface as follows:
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<edit-config>
<target>
<running/>
</target>
<config>
<interfaces>
<interface>
<name>lo0</name>
<description>loopback</description>
</interface>
</interfaces>
</config>
</edit-config>
</rpc>
Then the configuration of interface "lo0" is present in <operational>
as follows:
<interfaces xmlns:or="urn:ietf:params:xml:ns:yang:ietf-origin"
or:origin="or:intended">
<interface>
<name>lo0</name>
<description>loopback</description>
<ip-address or:origin="or:system">127.0.0.1</ip-address>
<ip-address or:origin="or:system">::1</ip-address>
</interface>
</interfaces>
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4.4.3. Declaring A System-defined Node in <running> Explicitly
In the environment which offline validation of <running> is required,
a client need to declare the system-defined configurations that are
actually referenced. Here is an example of a client explicitly
declaring "lo0" in <running>. The client configures a "lo0"
interface only with the list key "name" as follows:
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<edit-config>
<target>
<running/>
</target>
<config>
<interfaces>
<interface>
<name>lo0</name>
</interface>
</interfaces>
</config>
</edit-config>
</rpc>
A read-back of <running> should looks like:
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<edit-config>
<target>
<running/>
</target>
<config>
<interfaces>
<interface>
<name>lo0</name>
</interface>
</interfaces>
</config>
</edit-config>
</rpc>
5. Discovering System Configuration
There are two ways to discover system configuration: a "with-system"
query parameter and a <system> configuration datastore.
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5.1. The "with-system" Query Parameter
As defined in Section 1.3 and Section 1.4, All the system
configuration will be implicitly hidden in <running>, hence the
client can retrieve them through standard operations defined in YANG-
driven management protocols such as NETCONF and RESTCONF with a
"with-system" parameter to get a merged view.
All servers MUST implement a "with-system" parameter.
5.2. The <system> Configuration Datastore
This section is not applicable to non-NMDA servers. NMDA servers
SHOULD implement a <system> configuration datastore, and they SHOULD
also implement the <intended> datastore, which can be used as an
alternative to "with-system" parameter.
Following guidelines for defining datastores in the appendix A of
[RFC8342], this document introduces a new optional datastore resource
named 'system' that represents the system configuration. A device
MAY implement the mechanism defined in this document without
implementing the "system" datastore, which would only eliminate the
ability to programmatically determine the system configuration.
* Name: "system"
* YANG modules: all
* YANG nodes: all "config true" data nodes
* Management operations: The content of the datastore is set by the
server in an implementation dependent manner. The content can not
be changed by management operations via NETCONF, RESTCONF,the CLI,
etc, but may change itself by upgrades and/or when resource-
conditions are met. The datastore can be read using the standard
NETCONF/RESTCONF protocol operations.
* Origin: This document does not define any new origin identity when
it interacts with <intended> datastore and finally flows into
<operational>. The "system" origin Metadata Annotation [RFC7952]
is used to indicate the origin of a data item.
Comment: Should we define any new origin identity to indicate new
source of system configuration datastore?
* Protocols: YANG-driven management protocols, such as NETCONF and
RESTCONF.
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* Defining YANG module: "ietf-system".
The datastore's content is populated by the server and read-only to
clients. Upon the content is created or changed, it will be merged
into <intended> datastore. Unlike <factory-default>[RFC8808], it MAY
change dynamically, e.g., depending on factors like during device
upgrade or system-controlled resources(e.g., HW available) and the
<system> datastore does not have to persist across reboots. <factory-
reset> RPC operation defined in [RFC8088] can reset it to its factory
default configuration without including configuration generated due
to the system update or client-enabled functionality.
6. The "ietf-netconf-with-system" Module
6.1. Data Model Overview
This YANG module augments NETCONF <get> and <get-config> operation,
which is designed to make implicitly hidden system configuration
visible via a "with-system" parameter.
The following tree diagram [RFC8340] illustrates the "ietf-netconf-
with-system" module:
module: ietf-netconf-with-system
augment /nc:get-config/nc:input:
+---w with-system? empty
augment /nc:get/nc:input:
+---w with-system? empty
The following tree diagram [RFC8340] illustrates "get" and "get-
config" rpcs defined in "ietf-netconf" augmented by "ietf-netconf-
with-system" module :
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rpcs:
+---x get-config
| +---w input
| | +---w source
| | | +---w (config-source)
| | | +--:(candidate)
| | | | +---w candidate? empty {candidate}?
| | | +--:(running)
| | | | +---w running? empty
| | | +--:(startup)
| | | +---w startup? empty {startup}?
| | +---w filter? <anyxml>
| | +---w with-system? empty
| +--ro output
| +--ro data? <anyxml>
+---x get
| +---w input
| | +---w filter? <anyxml>
| | +---w with-system? empty
| +--ro output
| +--ro data? <anyxml>
6.2. Example Usage
This section gives an example of request/response pairs with and
without the "with-system" query parameter. The YANG module used are
shown in Appendix C.2 of [RFC8342].
Suppose the following data is added to <running>:
{
"bgp": {
"local-as": "64501",
"peer-as": "64502",
"peer": {
"name": "2001:db8::2:3"
}
}
}
All the messages are presented in a protocol-independent manner.
JSON is used only for its conciseness.
REQUEST(without a "with-system" query parameter):
Target:/bgp
Query Parameter:
with-defaults: report-all
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RESPONSE(both bgp/peer/local-as and bgp/peer/peer-as have default
values for a peer. "local-port" leaf is not present in <running>):
{
"bgp": {
"local-as": "64501",
"peer-as": "64502",
"peer": {
"name": "2001:db8::2:3",
"local-as": "64501",
"peer-as": "64502",
"remote-port": "179",
"state": "established"
}
}
}
REQUEST(with a "with-system" query parameter):
Target:/bgp
Query Parameter:
with-system
with-defaults: report-all
RESPONSE(local-port leaf value is supplied by the system):
{
"bgp": {
"local-as": "64501",
"peer-as": "64502",
"peer": {
"name": "2001:db8::2:3",
"local-as": "64501",
"peer-as": "64502",
"local-port": "60794",
"remote-port": "179",
"state": "established"
}
}
}
6.3. YANG Module
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<CODE BEGINS>
file="ietf-netconf-with-system@2021-05-14.yang"
module ietf-netconf-with-system {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-netconf-with-system";
prefix ncws;
import ietf-netconf {
prefix nc;
reference
"RFC 6241: Network Configuration Protocol (NETCONF)";
}
organization
"IETF NETMOD (Network Modeling) Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/netmod/>
WG List: <mailto:netmod@ietf.org>";
description
"This module defines an extension to the NETCONF protocol
that allows the NETCONF client to control how system configuration
data are handled by the server in particular NETCONF operations.
Copyright (c) 2010 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
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.";
// RFC Ed.: replace XXXX with actual RFC number and remove this note
revision 2021-05-14 {
description
"Initial version.";
reference
"RFC XXXX: System configuration Data handling Behavior";
}
augment /nc:get-config/nc:input {
description " Allows the get-config operation to use
with-system to retrieve the complete system configuration.";
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leaf with-system {
type empty ;
description
"Support system configuration retrieval on
conventional configuration datastore. ";
}
}
augment /nc:get/nc:input {
description " Allows the get operation to use
with-system to retrieve the complete system configuration.";
leaf with-system {
type empty ;
description
"Support system configuration retrieval on
running datastore.";
}
}
}
<CODE ENDS>
7. The "ietf-system-datastore" Module
7.1. Data Model Overview
This YANG module defines a new YANG identity named "system" that uses
the "ds:datastore" identity defined in [RFC8342]. Note that no new
origin identity is defined in this document, the "or:system" origin
Metadata Annotation [RFC7952] is used to indicate the origin of a
data item.
The following diagram illustrates the relationship amongst the
"identity" statements defined in the "ietf-system-datastore" and
"ietf-datastores" YANG modules
Identities:
+--- datastore
| +--- conventional
| | +--- running
| | +--- candidate
| | +--- startup
| | +--- system
| | +--- intended
| +--- dynamic
| +--- operational
The diagram above uses syntax that is similar to but not defined in [RFC8340].
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7.2. Example Usage
This section gives an example of data retrieval from <system>.
Suppose the following data is added to <running>:
{
"bgp": {
"local-as": "64501",
"peer-as": "64502",
"peer": {
"name": "2001:db8::2:3"
}
}
}
All the messages are presented in a protocol-independent manner.
JSON is used only for its conciseness.
REQUEST:
Datastore: <system>
Target:/bgp
RESPONSE("local-port" leaf value is supplied by the system):
{
"bgp": {
"peer": {
"local-port": "60794"
}
}
}
7.3. YANG Module
<CODE BEGINS>
file="ietf-system-datastore@2021-05-14.yang"
module ietf-system-datastore {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-system-datastore";
prefix sysds;
import ietf-datastores {
prefix ds;
reference
"RFC 8342: Network Management Datastore Architecture(NMDA)";
}
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organization
"IETF NETMDOD (Network Modeling) Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/netmod/>
WG List: <mailto:netmod@ietf.org>";
description
"This module defines a new YANG identity that uses the
ds:datastore identity defined in [RFC8342].
Copyright (c) 2010 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
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.";
// RFC Ed.: replace XXXX with actual RFC number and remove this note
revision 2021-05-14 {
description
"Initial version.";
reference
"RFC XXXX: System configuration Data handling Behavior";
}
identity system {
base ds:conventional;
description
"This read-only datastore contains the complete configuration
provided by the system itself.";
}
}
<CODE ENDS>
8. IANA Considerations
8.1. The "IETF XML" Registry
This document registers two XML namespace URNs in the 'IETF XML
registry', following the format defined in [RFC3688].
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URI: urn:ietf:params:xml:ns:yang:ietf-netconf-with-system
Registrant Contact: The IESG.
XML: N/A, the requested URIs are XML namespaces.
URI: urn:ietf:params:xml:ns:yang:ietf-system-datastore
Registrant Contact: The IESG.
XML: N/A, the requested URIs are XML namespaces.
8.2. The "YANG Module Names" Registry
This document registers one module name in the 'YANG Module Names'
registry, defined in [RFC6020] .
name: ietf-netconf-with-system
prefix: ncws
namespace: urn:ietf:params:xml:ns:yang:ietf-netconf-with-system
RFC: XXXX // RFC Ed.: replace XXXX and remove this comment
name: ietf-system-datastore
prefix: sys
namespace: urn:ietf:params:xml:ns:yang:ietf-system-datatstore
RFC: XXXX // RFC Ed.: replace XXXX and remove this comment
9. Security Considerations
9.1. Regarding the "ietf-netconf-with-system" YANG Module
The YANG module defined in this document extends the base operations
for NETCONF [RFC6241] and RESTCONF [RFC8040]. The lowest NETCONF
layer is the secure transport layer, and the mandatory-to-implement
secure transport is Secure Shell (SSH) [RFC6242]. The lowest
RESTCONF layer is HTTPS, and the mandatory-to-implement secure
transport is TLS [RFC8446].
The Network Configuration Access Control Model (NACM) [RFC8341]
provides the means to restrict access for particular NETCONF users to
a preconfigured subset of all available NETCONF protocol operations
and content.
The security considerations for the base NETCONF protocol operations
(see Section 9 of [RFC6241] apply to the new extended RPC operations
defined in this document.
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9.2. Regarding the "ietf-system-datastore" YANG Module
The YANG module defined in this document extends the base operations
for NETCONF [RFC6241] and RESTCONF [RFC8040]. The lowest NETCONF
layer is the secure transport layer, and the mandatory-to-implement
secure transport is Secure Shell (SSH) [RFC6242]. The lowest
RESTCONF layer is HTTPS, and the mandatory-to-implement secure
transport is TLS [RFC8446].
The Network Configuration Access Control Model (NACM) [RFC8341]
provides the means to restrict access for particular NETCONF users to
a preconfigured subset of all available NETCONF protocol operations
and content.
10. Contributors
Chongfeng Xie
China Telecom
Beijing
China
Email: xiechf@chinatelecom.cn
Kent Watsen
Watsen Networks
Email: kent+ietf@watsen.net
Jason Sterne
Nokia
Email: jason.sterne@nokia.com
Acknowledgements
Thanks to Robert Wilton, Balazs Lengyel, Andy Bierman, Jan Lindbland,
Juergen Schoenwaelder, Alex Clemm, Timothy Carey for reviewing, and
providing important input to, this document.
References
Normative References
[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>.
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Informative References
[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>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/info/rfc7950>.
[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>.
[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>.
[RFC8407] Bierman, A., "Guidelines for Authors and Reviewers of
Documents Containing YANG Data Models", BCP 216, RFC 8407,
DOI 10.17487/RFC8407, October 2018,
<https://www.rfc-editor.org/info/rfc8407>.
[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/info/rfc8525>.
[RFC8808] Wu, Q., Lengyel, B., and Y. Niu, "A YANG Data Model for
Factory Default Settings", RFC 8808, DOI 10.17487/RFC8808,
August 2020, <https://www.rfc-editor.org/info/rfc8808>.
Appendix A. Key Use Cases
Following provides three use cases related to system-defined
configuration lifecycle management. The simple interface data model
defined in Appendix C.3 of [RFC8342] is used. For each use case,
snippets of <running>, <system>, <intended> and <operational> are
shown.
A.1. Device Powers On
<running>:
No configuration for “lo0†appears in <running>;
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<system>:
<interfaces>
<interface>
<name>lo0</name>
<ip-address>127.0.0.1</ip-address>
<ip-address>::1</ip-address>
</interface>
</interfaces>
<intended>:
<interfaces>
<interface>
<name>lo0</name>
<ip-address>127.0.0.1</ip-address>
<ip-address>::1</ip-address>
</interface>
</interfaces>
<operational>:
<interfaces xmlns:or="urn:ietf:params:xml:ns:yang:ietf-origin"
or:origin="or:system">
<interface>
<name>lo0</name>
<ip-address>127.0.0.1</ip-address>
<ip-address>::1</ip-address>
</interface>
</interfaces>
A.2. Client Commits Configuration
If a client creates an interface "et-0/0/0" but the interface does
not physically exist at this point:
<running>:
<interfaces>
<interface>
<name>et-0/0/0</name>
<description>Test interface</description>
</interface>
</interfaces>
<system>:
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<interfaces>
<interface>
<name>lo0</name>
<ip-address>127.0.0.1</ip-address>
<ip-address>::1</ip-address>
</interface>
</interfaces>
<intended>:
<interfaces>
<name>lo0</name>
<ip-address>127.0.0.1</ip-address>
<ip-address>::1</ip-address>
</interface>
<interface>
<name>et-0/0/0</name>
<description>Test interface</description>
</interface>
<interface>
</interfaces>
<operational>:
<interfaces xmlns:or="urn:ietf:params:xml:ns:yang:ietf-origin"
or:origin="or:intended">
<interface or:origin="or:system">
<name>lo0</name>
<ip-address>127.0.0.1</ip-address>
<ip-address>::1</ip-address>
</interface>
</interfaces>
A.3. Operator Installs Card into a Chassis
<running>:
<interfaces>
<interface>
<name>et-0/0/0</name>
<description>Test interface</description>
</interface>
</interfaces>
<system>:
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<interfaces>
<interface>
<name>lo0</name>
<ip-address>127.0.0.1</ip-address>
<ip-address>::1</ip-address>
</interface>
<interface>
<name>et-0/0/0</name>
<mtu>1500</mtu>
</interface>
</interfaces>
<intended>:
<interfaces>
<name>lo0</name>
<ip-address>127.0.0.1</ip-address>
<ip-address>::1</ip-address>
</interface>
<interface>
<name>et-0/0/0</name>
<description>Test interface</description>
<mtu>1500</mtu>
</interface>
<interface>
</interfaces>
<operational>:
<interfaces xmlns:or="urn:ietf:params:xml:ns:yang:ietf-origin"
or:origin="or:intended">
<interface or:origin="or:system">
<name or:origin>lo0</name>
<ip-address>127.0.0.1</ip-address>
<ip-address>::1</ip-address>
</interface>
<interface>
<name>et-0/0/0</name>
<description>Test interface</description>
<mtu or:origin="or:system">1500</mtu>
</interface>
<interface>
</interfaces>
Appendix B. Changes between Revisions
v02 - v00
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* Restructure the document content based on input in the system
defined configuration interim meeting.
* Updates NMDA to define a read-only conventional configuration
datastore called "system".
* Retrieval of implicit hidden system configuration via <get><get-
config> with "with-system" parameter to support non-NMDA servers.
* Provide system defined configuration classification.
* Define Static Characteristics and dynamic behavior for system
defined configuration.
* Separate "ietf-system-datastore" Module from "ietf-netconf-with-
system" Module.
* Provide usage examples for dynamic behaviors.
* Provide usage examples for two YANG modules.
* Provide three use cases related to system-defined configuration
lifecycle management.
* Classify the relation with <factory-default>.
Appendix C. Open Issues tracking
* Backward compatibility:consider the communication between the
server and the new client or the old client simultaneously.
* Running always be valid? The client might need to understand how
to merge if offline validation on running is used.
* Immutable flag
Authors' Addresses
Qiufang Ma (editor)
Huawei
101 Software Avenue, Yuhua District
Nanjing
Jiangsu, 210012
China
Email: maqiufang1@huawei.com
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Feng Chong
Huawei
101 Software Avenue, Yuhua District
Nanjing
Jiangsu, 210012
China
Email: frank.fengchong@huawei.com
Qin Wu
Huawei
101 Software Avenue, Yuhua District
Nanjing
Jiangsu, 210012
China
Email: bill.wu@huawei.com
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