JNCIA-DevOps Junos REST API Practice Test 2 — 15 Questions

Question 1

An engineer is designing an automated failover script that needs to discard candidate configuration changes made via the Junos REST API. How should this discard action be performed?

Accepted Answer

Send a request to the configuration discard/rollback endpoint or invoke the discard-changes RPC via the REST API.. To discard candidate configuration changes via the Junos REST API, you must send a request to the configuration discard/rollback endpoint or invoke the discard-changes RPC. The REST API provides a specific endpoint for this action, typically a POST to /api/configuration/discard or using the 'discard-changes' RPC. This is the correct way to revert uncommitted changes.

Answer

Send an HTTP GET request with ?action=reset.

Answer

Issue an HTTP DELETE request to the root /api/configuration path.

Answer

Restart the routing engine process (RE switchover).

Question 2

Which Junos configuration command enables the REST API daemon to start automatically upon device boot?

Accepted Answer

set system services jpagent. Enabling any system service like jpagent under 'set system services jpagent' ensures it starts automatically upon device boot and initialization.

Answer

set chassis auto-restart jpagent

Answer

set management daemon jpagent start

Answer

set system boot-services rest

Question 3

When configuring advanced options for the Junos REST API jpagent, which THREE parameters or sub-statements can be configured under the 'set system services jpagent' hierarchy? (Choose three)

Accepted Answer

traceoptions. Under the 'set system services jpagent' hierarchy, the jpagent (Junos REST API agent) supports the 'traceoptions' sub-statement (B), which enables logging and debugging of jpagent activity via configured trace files and flags. It also supports the 'https' sub-statement (C), which enables the HTTPS transport for the REST API and allows configuration of TLS-related parameters such as certificates and addresses. The 'port' parameter (E) is configurable to specify the TCP port on which jpagent listens for REST API requests (default 3000). Options A (bgp-peer-group) and D (ethernet-switching) are not valid under 'system services jpagent'; bgp-peer-group belongs to BGP configuration and ethernet-switching is a switching-options/protocols hierarchy, neither of which is a jpagent parameter.

Answer

bgp-peer-group

Answer

ethernet-switching

Question 4

An automation engineer needs to enable and configure the Junos REST API service on an SRX Series device using the CLI. Which configuration hierarchy must be used to enable the service and configure its transport protocol?

Accepted Answer

set system services web-management https. The Junos REST API service is configured under the 'system services web-management http' or 'https' hierarchy in the Junos CLI.

Answer

set management-plane api rest

Answer

set system services rest http port 3000

Answer

set protocols rest-api enable

Question 5

An administrator wants to fetch operational data representing interface statistics using the Junos REST API by issuing an HTTP GET request. Which URI structure correctly targets the 'get-interface-information' RPC via the REST API endpoint?

Accepted Answer

/api/st/rest/rpc/get-interface-information. The Junos REST API allows executing operational RPCs using the path '/rpc/get-interface-information'.

Answer

/api/core/rest/rpc/get-interface-information

Answer

/api/space/rest/rpc/get-interface-information

Answer

/api/font/rest/rpc/get-interface-information

Question 6

Which statement accurately describes how the Junos REST API handles configuration locking compared to NETCONF workflows?

Accepted Answer

NETCONF requires explicit lock commands, whereas the Junos REST API handles configuration locking implicitly during API-driven edit sessions.. The Junos REST API wraps configuration edits in an implicit lock-and-unlock cycle tied to the HTTP session, so the client does not have to issue explicit lock RPCs. NETCONF, by contrast, exposes explicit and operations that the client must invoke around a candidate configuration edit. This difference means REST clients get simpler code but less granular control over lock lifetime than NETCONF clients.

Answer

NETCONF does not support configuration locking at all.

Answer

The Junos REST API uses exclusive database locking for every GET request.

Answer

The Junos REST API requires manual SSH tunnel establishment before locks can be applied.

Question 7

An administrator is planning an automation architecture using the Junos REST API. Which THREE statements are correct regarding its endpoints, authentication, and usage? (Choose three)

Accepted Answer

Operational commands and RPCs can be executed by targeting the /api/st/rest/rpc/ URI path.. Junos REST API supports HTTP Basic Authentication, allows executing operational RPCs, and supports JSON representation of data.

Answer

The REST API requires proprietary client software installed on the Junos device.

Answer

The REST API bypasses the Junos management daemon (MGD) entirely.

Question 8

A DevOps engineer is automating the backup of Junos device configurations using the Junos REST API. The engineer wants to retrieve the entire running configuration in text format. Which HTTP request should the engineer use?

Accepted Answer

GET /rest/rpc/get-configuration with Accept header set to application/text. The Junos REST API uses content negotiation via the Accept header to determine the response format. To get the running configuration in text format, you send a GET request to the get-configuration RPC endpoint with the Accept header set to 'application/text' or 'text/plain'. This returns the configuration as plain text, which is suitable for backup. Other parameters or methods are either incorrect or not standard for this purpose.

Answer

GET /rest/rpc/get-configuration?format=text

Answer

GET /rest/rpc/get-configuration?format=text&database=running

Answer

POST /rest/rpc/get-configuration with a JSON body specifying format text

Question 9

A developer is using the Junos REST API to commit a candidate configuration. The commit operation must include a comment and synchronize the commit across all Routing Engines in a dual-RE chassis. Which HTTP request should the developer use?

Accepted Answer

POST https://<device>/rest/commit?comment=Automated%20commit&synchronize=true. The Junos REST API commit operation is performed via POST to /rest/commit/. Commit options such as a comment and synchronization are specified as query parameters. The correct parameters are 'comment' for the commit message and 'synchronize' to synchronize across Routing Engines. This mirrors the CLI commit command with those options.

Answer

PUT https://<device>/rest/commit?comment=Automated%20commit&synchronize=true

Answer

POST https://<device>/rest/commit?message=Automated%20commit&sync=true

Answer

POST https://<device>/rest/commit with a JSON body containing {"comment":"Automated commit","synchronize":true}

Question 10

An administrator is using the Junos REST API to retrieve operational data from a device. The administrator wants to filter the output to include only a specific interface's statistics. Which HTTP method and URI pattern should be used to achieve this?

Accepted Answer

POST /rpc/get-interface-information with XML body ge-0/0/0. To retrieve filtered operational data, the Junos REST API requires a POST to the RPC endpoint with an XML body containing the desired arguments. For interface statistics, the get-interface-information RPC with the interface-name argument returns only the specified interface's data. This method ensures precise filtering.

Answer

GET /rest/operational/interface/ge-0/0/0

Answer

PUT /rpc/get-interface-information/ge-0/0/0

Answer

GET /rest/op/interface?name=ge-0/0/0

Question 11

An administrator wants to use the Junos REST API to retrieve the output of the 'show version' command in JSON format. Which HTTP request should be used?

Accepted Answer

GET /rpc/get-software-information with Accept: application/json. The 'show version' command is mapped to the get-software-information RPC in the Junos REST API. To retrieve its output in JSON, you issue a GET request to /rpc/get-software-information with the Accept header set to application/json. This returns a structured JSON object containing version details. The other options either use incorrect RPC names, inappropriate HTTP methods, or the wrong RPC for the desired information. The correct choice precisely matches the CLI command and uses the proper REST conventions.

Answer

GET /rpc/get-system-information with Accept: application/json

Answer

POST /rpc/get-software-information with a JSON body containing {"format":"json"}

Answer

GET /rpc/show-version with Accept: application/json

Question 12

A developer is using the Junos REST API to load a configuration change onto a device. The change involves setting the description on interface ge-0/0/1. The developer wants to ensure that the configuration is validated before being committed. Which sequence of API calls should the developer use?

Accepted Answer

POST to /config with the new configuration, then POST to /rpc/check, then POST to /rpc/commit. To load and validate configuration via the Junos REST API, use POST to /config to load the change, then POST to /rpc/check to validate the candidate configuration. If validation passes, POST to /rpc/commit to apply the changes. This sequence ensures that errors are caught before commit, meeting the developer's requirement.

Answer

POST to /config with the new configuration, then POST to /rpc/commit-check, then POST to /rpc/commit

Answer

PUT to /config with the new configuration, then POST to /rpc/commit with the 'check' argument

Answer

POST to /config with the new configuration, then POST to /rpc/commit with the 'validate' parameter

Question 13

A network engineer is designing a script that uses the Junos REST API to manage configurations. The script must perform the following operations: (1) lock the candidate configuration, (2) load a configuration change, (3) commit the change, and (4) unlock the configuration. Which THREE HTTP methods and endpoints are required to accomplish these operations? (Choose three.)

Accepted Answer

POST to /rpc/commit with optional arguments for commit options. To lock, load, and commit configuration changes via the Junos REST API, the required operations are: POST to /rpc/lock-configuration to lock the candidate, POST to /config to load the change, and POST to /rpc/commit to commit. These three steps ensure exclusive access, configuration loading, and activation. Unlocking is not among the three operations specified in the stem.

Answer

PUT to /config with the configuration data in JSON format

Answer

POST to /rpc/unlock-configuration with XML body specifying the configuration

Question 14

When executing a configuration change via the Junos REST API, what is the role of the HTTP DELETE method?

Accepted Answer

To delete a specific configuration hierarchy or statement from the candidate configuration.. In the context of the Junos REST API, the HTTP DELETE method is used to remove a specific configuration object or subtree, analogous to deleting a statement in the Junos CLI or removing an element in NETCONF.

Answer

To clear operational state counters such as interface packet counters.

Answer

To terminate an active REST API session and revoke the auth token.

Answer

To discard the entire candidate configuration.

Question 15

Which data serialization formats are natively supported by the Junos REST API for both input and output payloads?

Accepted Answer

JSON and XML. The Junos REST API natively supports both JSON and XML data formats for interacting with operational and configuration data.

Answer

CSV and HTML

Answer

JSON and YAML

Answer

YAML and Protocol Buffers