JNCIA-DevOps Junos REST API — 25 Questions

Question 1

An automation engineer needs to check if the Junos REST API is actively running and responsive on a managed device without querying heavy configuration data. Which lightweight endpoint can be queried?

Accepted Answer

/api/initial. The Junos REST API provides an initial or root status endpoint, often /api/initial or root discovery endpoints, to verify service availability and root resource links.

Answer

/healthz

Answer

/api/v1/system/ping

Answer

/status/ping

Question 2

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 3

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 4

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 5

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 6

An administrator wishes to secure their Junos REST API connections by configuring HTTPS instead of plain HTTP. Which command under 'system services jpagent' accomplishes this?

Accepted Answer

set system services jpagent https. To enable HTTPS for the Junos REST API agent, the administrator must configure the 'https' option under 'set system services jpagent'.

Answer

set system services netconf ssl

Answer

set security ipsec-vpn

Answer

set system services rest secure

Question 7

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

Question 8

Which service daemon must be explicitly enabled in the Junos CLI configuration to allow REST API requests to be processed by the routing engine?

Accepted Answer

set system services jpagent. The Junos REST API is managed by the 'jpagent' (Junos Plugin Agent) service. It must be enabled under the 'system services' hierarchy for REST API requests to function.

Answer

set system services api-daemon

Answer

set system services netconf

Answer

set system services rest http

Question 9

You are writing a Python script to retrieve interface statistics from a Junos device using the REST API. You use HTTP Basic Authentication. Which HTTP header must be included to pass the encoded credentials correctly?

Accepted Answer

Authorization. HTTP Basic Authentication requires the 'Authorization' header containing the keyword 'Basic' followed by the Base64-encoded username:password string.

Answer

Proxy-Authenticate

Answer

Junos-Auth-Token

Answer

X-API-Key

Question 10

An automation engineer is trying to retrieve operational data from a Junos device using the REST API. They send an HTTP GET request to the URI path 'http://192.168.1.1:3000/api/font/operational/system/information', but the request fails with a 404 Not Found error. What is the cause of this failure?

Accepted Answer

The URI path contains an invalid prefix segment 'font' instead of the required API root structure.. The correct base path for Junos REST API operational data uses 'rpc' or 'initial' or specific resource endpoints like /api/restful/rit/rpc, but the standard path prefix for RPCs and operational data via the Junos REST API begins with /api/operational/ rather than /api/font/operational/.

Answer

Authentication credentials were missing from the HTTP header.

Answer

The port 3000 is reserved for NETCONF and cannot be used for REST API requests.

Answer

Operational data retrieval requires an HTTP POST method instead of GET.

Question 11

When comparing NETCONF and the Junos REST API workflows, which statement accurately describes how configuration locks are handled?

Accepted Answer

NETCONF requires explicit lock and unlock commands, whereas REST API transactions typically manage locks implicitly during request execution.. NETCONF explicitly requires lock and unlock operations on configuration datastores (candidate/running). The Junos REST API abstracts state management or handles implicit locking depending on the specific API call, whereas NETCONF leaves lock management entirely to the client's explicit RPC control.

Answer

Neither protocol utilizes locking mechanisms since Junos uses optimistic concurrency control.

Answer

The Junos REST API enforces exclusive global locking which prevents any concurrent NETCONF sessions.

Answer

Both NETCONF and Junos REST API require the client to manually issue an explicit lock RPC before making changes.

Question 12

An engineer needs to modify a configuration parameter using the Junos REST API via an HTTP PUT request. They include the Content-Type header as 'application/json'. However, the device rejects the payload. What is the correct Content-Type or Accept header requirement for configuration manipulation payload representation in Junos REST API?

Accepted Answer

application/vnd.juniper.netconf.config+json. Junos REST API supports both JSON and XML representations. When sending configuration payloads, the Content-Type must match the format being transmitted, such as application/vnd.juniper.netconf.config+json or application/json depending on the API version, but application/vnd.juniper.netconf.config+json is specifically designed for structural configuration mapping.

Answer

application/x-www-form-urlencoded

Answer

text/xml only

Answer

multipart/form-data

Question 13

An engineer compares NETCONF and Junos REST API when fetching operational state via RPCs. How does the REST API transmit an RPC request compared to a NETCONF <rpc> wrapper?

Accepted Answer

REST API uses HTTP POST/GET requests targeting specific RPC URI paths, translating JSON/XML parameters, whereas NETCONF sends raw XML RPC elements over a dedicated SSH subsystem.. NETCONF wraps queries in an XML <rpc> element over a persistent SSH channel. The Junos REST API maps RPCs to HTTP methods (such as GET or POST) targeting specific URI endpoints under /api/operational/ or /api/rpc/, translating the payload to JSON or XML without needing a raw NETCONF XML envelope.

Answer

There is no functional difference; REST API is simply an alias for NETCONF over port 830.

Answer

NETCONF uses HTTP status codes for error reporting, while REST API uses standard syslog messages.

Answer

REST API requires a persistent WebSocket connection that tunnels NETCONF XML streams.

Question 14

How does the Junos REST API handle configuration commits compared to NETCONF workflow behavior?

Accepted Answer

NETCONF utilizes explicit lock, candidate modification, and commit RPC workflows, while REST API provides resource-based endpoints where configuration changes can trigger auto-commits or be committed via dedicated commit URIs.. In NETCONF, changes are made to the candidate datastore and must be explicitly committed using the <commit> RPC. In the Junos REST API, configuration changes made via PUT, POST, or DELETE can either auto-commit depending on the API call parameters or require a separate commit action, but unlike NETCONF's explicit candidate/running model, REST abstracts transactions into resource endpoints where commit behaviors are managed via query parameters or dedicated commit endpoints.

Answer

REST API does not support committing configurations; it is strictly read-only for operational data.

Answer

NETCONF requires an explicit <commit> RPC, whereas the Junos REST API executes modifications directly against the running configuration with optional commit flags.

Answer

Both protocols bypass the candidate datastore entirely and write directly to NVRAM.

Question 15

When an automation script issues a POST request to create a new static route via the Junos REST API, what HTTP status code indicates that the resource was successfully created?

Accepted Answer

201 Created. In standard HTTP REST semantics, a successful creation request resulting in a new resource returns HTTP status code 201 Created.

Answer

200 OK

Answer

302 Found

Answer

204 No Content

Question 16

An administrator wants to retrieve the configuration of a specific interface (e.g., ge-0/0/0) using the Junos REST API. Which URI structure is appropriate for fetching this configuration resource in JSON format?

Accepted Answer

/api/configuraton/interfaces/interface/name/ge-0/0/0. The Junos REST API uses structured paths matching the configuration hierarchy, typically prefixed by /api/configuraton/interfaces/interface/ge-0/0/0 or similar resource roots depending on the Junos release.

Answer

/rpc/get-config?interface=ge-0/0/0

Answer

/netconf?subsystem=ge-0/0/0

Answer

/api/operational/interfaces/ge-0/0/0

Question 17

When configuring the Junos REST API, an administrator restricts access to a specific port and enables SSL. Which configuration statement sets the secure HTTPS port to 8443?

Accepted Answer

set system services jpagent https port 8443. To customize the HTTPS port for the jpagent service in Junos, the administrator uses the 'set system services jpagent https port 8443' command.

Answer

set protocols rest-api https port 8443

Answer

set system services rest port 8443 secure

Answer

set system services netconf https-port 8443

Question 18

What is the default TCP port used by the Junos jpagent for unencrypted HTTP REST API connections?

Accepted Answer

3000. The Junos REST API daemon (jpagent) listens on TCP port 3000 by default for HTTP traffic, and port 3443 for HTTPS traffic.

Answer

80

Answer

830

Answer

8080

Question 19

An engineer executes an HTTP GET request to retrieve interface operational details using the Junos REST API, but receives a 403 Forbidden status code. What is the most likely reason?

Accepted Answer

The authenticated user account lacks sufficient RBAC permissions to access the requested resource.. A 403 Forbidden status code indicates that the authentication credentials provided were valid (otherwise it would be 401), but the user account lacks the necessary RBAC permissions or class privileges to access the requested resource.

Answer

The HTTP request method should have been POST.

Answer

The Accept header was missing from the GET request.

Answer

The jpagent service is disabled on the device.

Question 20

Which user credential validation mechanism does the Junos REST API use by default when authenticating incoming API calls?

Accepted Answer

Junos local user database or AAA via HTTP Basic Authentication. The Junos REST API authenticates incoming requests against the Junos local user database or configured AAA servers (RADIUS/TACACS+) using standard HTTP Basic Authentication.

Answer

OAuth 2.0 bearer tokens generated by an external IdP

Answer

Pre-shared API secret keys stored in environment variables

Answer

SSH public key authentication exclusively