Understanding the YANG Modules for Junos Operational Commands

Juniper Networks publishes YANG modules that define the remote procedure calls (RPCs) for Junos operational mode commands. Due to the large number of operational commands, there are multiple YANG modules for each device family. There is a module for each top-level operational command group (clear, file, monitor, and so on) where there is at least one command within that hierarchy with an RPC equivalent. There is also a separate module for each area within the show command hierarchy.

The operational command modules define the RPCs corresponding to the operational commands in the command hierarchy area indicated in the filename. The following example shows a portion of the module containing the RPCs for commands in the clear command hierarchy:

user@host> file show /var/tmp/yang/junos-rpc-clear@2017-01-01.yang
/*
 * Copyright (c) 2017 Juniper Networks, Inc.
 * All rights reserved.
 */
 module junos-rpc-clear {
   namespace "http://yang.juniper.net/junos/rpc/clear";

   prefix clear;

   import junos-common-types {
     prefix jt;
   }

   organization "Juniper Networks, Inc.";

   contact "yang-support@juniper.net";

   description "Junos RPC YANG module for clear command(s)";

   revision 2017-01-01 {
     description "Junos: 17.4R1.17";
   }

   rpc clear-cli-logical-system {
     description "Clear logical system association";
     output {
       leaf output {
         type string;
       }
     }
   }
   rpc clear-cli-satellite {
     description "Clear satellite association";
     output {
       leaf output {
         type string;
       }
     }
   }
   ...

YANG defines operations using the rpc statement. The RPC definition can include input and output substatements that describe the operation's input and output parameters. Starting in Junos OS Release 23.1R1 and Junos OS Evolved Release 23.2R1, the RPC's output statement includes an accurate output schema, and Junos devices emit the new schemas by default.

In earlier releases, the RPC's output schema includes the anyxml statement to represent an unkown chunk of XML in the RPC reply. To generate the RPC schemas containing the anyxml statement on a Junos device, configure the device-specific and emit-anyxml-in-rpc-output statements at the [edit system services netconf yang-modules] hierarchy level. After you configure the statements, the show system schema command generates the schemas that use anyxml.

You can download the Junos native YANG modules from the Juniper Networks download site or the Juniper/yang GitHub repository, or you can generate the modules on the local device. To generate the operational command YANG modules on the local device issue the show system schema format yang module module command. The Junos OS release determines the available command options.

• In Junos OS Release 17.3 and earlier, specify the juniper-command module to generate all of the operational command modules.

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  user@host> show system schema format yang module juniper-command

  Note:

  Starting in Junos OS Release 17.1, when you generate the juniper-command module, the output files are placed in the current working directory, which defaults to the user’s home directory. In Junos OS Release 16.2 and earlier, the output files are placed in the /var/tmp directory.

• In Junos OS Release 17.4R1 and later, specify an individual module name to return a single operational command module, or specify all-rpc to return all operational command modules.

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  user@host> show system schema format yang module all-rpc output-directory /var/tmp/yang

If you specify module juniper-command or module all-rpc, the output files include both native Junos operational command modules as well as any standard or custom operational command modules that have been added to the device. To use an RPC in your custom YANG module, you must import the module that contains the desired RPC into your custom module.

Starting in Junos OS Release 19.1R2 and 19.2R1, the show system schema command must include the output-directory command option and specify the directory in which to generate the file or files. In earlier releases, you can omit the output-directory option when requesting a single module to display the module in standard output.

You can configure the emit-extensions statement at the [edit system services netconf yang-modules] hierarchy level to emit the YANG schemas with additional Junos extension statements. The Junos extensions are defined in Understanding the Junos DDL Extensions YANG Module. The device emits the junos:command extension statement starting in Junos OS Release 22.4R1 and Junos OS Evolved Release 22.4R1.