Junos Genstate YANG Data Models

Starting in Junos OS Evolved Release 24.2R1, Juniper Networks publishes the genstate YANG modules. The genstate models are subscribable YANG models for operational state data on Junos devices. They are a YANG representation of the operational command output. The genstate model comprises a top-level module augmented by modules for each of the different operational state areas as they are published and made available.

Junos devices have a rich set of native state data. You can retrieve operational state information from Junos devices by executing operational commands or Junos XML RPCs on the device. However, you must still parse the command output to extract specific data. Juniper also provides the curated junos-state YANG data models that telemetry collectors can consume, but the models include only a subset of operational areas and states.

Junos devices expose a subset of Junos XML RPC response paths in telemetry under the genstate origin (genstate:). The origin identifies the schema for the subscription path. The corresponding telemetry YANG modules that define the schema are referred to as the genstate YANG modules. A gNMI telemetry collector can subscribe to the resource paths published in the genstate YANG modules to query for the corresponding state data on a device.

gNMI clients can use the gNMI subscribe RPC to subscribe to the genstate published paths. A client can use STREAM subscriptions in SAMPLE mode to request the data. ON_CHANGE mode is not supported. For information about using gNMI to subscribe to telemetry data, see the Junos Telemetry Interface User Guide.

The genstate YANG data models are published and updated in different releases. You can check the available models and supported paths for a given release in the following ways:

• View or download the modules from the Juniper/yang GitHub repository.

• Download the modules from the Juniper Networks website at https://www.juniper.net/support/downloads.

• Emit the modules on Junos devices.

• Emit available subscription paths on Junos devices as outlined in Map CLI Commands to Genstate Resource Paths and YANG Modules.

The genstate YANG data models comprise a top-level root module augmented by modules for each of the available operational state areas. The genstate schema uses origin 'genstate'.

The top-level module is as follows:

The top-level genstate module is augmented by the modules published for each operational state area. When you issue operational commands or RPCs on a Junos device, the device returns the XML output enclosed in a top-level element. The root-level tag name describes the enclosed data. For example, show interfaces commands return XML output that is enclosed in an <interface-information> tag. The genstate modules include this root tag name in the module name and filename to easily identify the data described in the module. The module prefix is based on the root tag name and so varies for each module.

For example, the junos-genstate-interface-information module describes the data that would normally be included in the <interface-information> element in Junos command and RPC output. Thus, the model defines the resource paths that are available for subscription by telemetry collectors for interface state data.

A telemetry collector can subscribe to the different resource paths as defined in the genstate models to query for state data on devices that support this feature. The genstate model uses the following syntax:

The path uses the origin genstate, a root tag named genstate, and the top-level tag name for the operational state area. For example, to subscribe to genstate resource paths for all interface-information state data, you would use the following path:

You can include supported child tags to retrieve state data for a specific resource. For example, a gNMI client can use the following path to retrieve the operational state for all interfaces:

The genstate resource paths can use simple path expressions to query data. You can use path-based and key-based filters. Table 1 outlines the supported expressions and provides some sample resource paths. Other query patterns are not supported. The path expressions support container, leaf, and key-based filtering and align with gNMI conventions, as outlined in Schema path encoding conventions for gNMI.

Path-based filters can select containers, lists, or leaf nodes. Key-based filters select a subset of list elements and support using precise values, specifying wildcards, or omitting the value. Specifying a wildcard or omitting a list key value matches all entries within a particular list.

We recommend that you always enclose the path in quotation marks. This approach prevents parsing errors in most environments and handles paths with spaces or other special characters.

For example, the following command uses quotation marks around the entire path:

You can use CLI pipe filter functions to discover the genstate YANG module and corresponding resource paths for a given show command. The options include:

• | display genstate subscription-paths—Display all resource paths available for subscription in the genstate YANG module associated with the given command.

• | display genstate yang-module-name—Display the name of the genstate YANG module that includes the data model and resource paths for the given command.

• | display xml genstate-path—Display the command output in XML and include the junos:genstate-path attribute for every emitted tag that is available for subscription. The attribute value is the genstate subscription path.

The following sections outline the options.

• Example: Retrieve the Genstate YANG Module Name
• Example: Retrieve All Subscription Paths in a Command's YANG Module
• Example: Retrieve Available Subscription Paths in Command Output

You can map a genstate resource path to the CLI command that generates the corresponding output. To map the genstate path to the command, use the show system data-models genstate command. Include the appropriate option and provide the path to the desired resource.

• In Junos OS and Junos OS Evolved Release 26.2R1 and later releases, use the genstate-path-cli-command-mapping option.

• In earlier releases, use the xpath-cli-command-mapping option.

The following example retrieves the command that generates the state data corresponding to the genstate:/genstate/system-information/os-version resource path.

Similarly, the following example maps the given resource path to the CLI command that includes that information in the output.

You can include list key values in the genstate path. When you issue the command or corresponding RPC and specify a list key in the path, enclose the list key value in single quotation marks and enclose the path in double quotation marks. The following examples request the command for genstate paths that specify a key.

Similarly, you can use the corresponding RPC to retrieve the same information.

If a device does not support a particular genstate path, the command returns an error. The message varies by release.

You can download Junos native YANG modules from the Juniper Networks download site or the Juniper/yang GitHub repository. You can also generate the modules on the local device. For instructions on downloading the modules, see Use Juniper Networks YANG Modules.

To emit the genstate YANG module files on the local device issue the show system schema format yang module module command. Specify an individual module name to return a single genstate module, or specify all-genstate to return all genstate modules. You must also specify an output directory for the files.

For example, the following commands create a directory, write all the genstate modules to that directory, and view the directory listing.