JNCIA-DevOps Junos REST API Practice Test 3 — 15 Questions

Question 1

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?

Choose an answer to begin — your selection is scored in the full session.

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 2

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 3

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 4

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 5

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

Question 6

When comparing error handling between NETCONF and the Junos REST API, how are protocol-level errors communicated back to the client?

Accepted Answer

NETCONF embeds error details inside XML tags, whereas REST API uses standard HTTP status codes accompanied by structured error response bodies.. NETCONF communicates errors via XML elements embedded in the response envelope. The Junos REST API leverages standard HTTP status codes (such as 400 Bad Request, 401, 403, 404, 500) combined with detailed error payloads in the response body.

Answer

NETCONF uses HTTP status codes, while REST API uses XML <rpc-error> tags.

Answer

NETCONF and REST API both use identical JSON error envelopes defined by RFC 7807.

Answer

Both protocols rely exclusively on system syslog files to report errors to the client API.

Question 7

An engineer needs to execute a custom Junos RPC (such as 'get-route-information') using the REST API. Which HTTP method and general URI structure should be used?

Accepted Answer

HTTP GET/POST targeting /api/operational/rpc/<rpc-name>. Custom RPCs in the Junos REST API are typically executed using HTTP GET or POST requests directed to the RPC execution endpoint, such as /api/operational/rpc/get-route-information or via the rpc resource path.

Answer

HTTP PATCH targeting /api/v1/rpc

Answer

HTTP DELETE targeting /rpc/clear/<rpc-name>

Answer

HTTP PUT targeting /api/configuration/rpc/<rpc-name>

Question 8

Which statement best describes the primary architectural difference between NETCONF and the Junos REST API?

Accepted Answer

NETCONF is a connection-oriented RPC protocol over SSH, while Junos REST API is a resource-oriented web API over HTTP/HTTPS.. NETCONF is a session-oriented, connection-oriented protocol running over SSH (port 830) using XML-encoded RPCs. The Junos REST API is a stateless (at the HTTP layer) resource-oriented web API running over HTTP/HTTPS (port 3000/3443) supporting JSON and XML.

Answer

NETCONF only supports JSON, while REST API only supports XML.

Answer

There are no architectural differences; REST API is simply an XML parser for NETCONF.

Answer

NETCONF is a web-based stateless API, whereas REST API requires a persistent SSH session.

Question 9

An automation script makes a REST API request to modify a Junos configuration. To ensure that the changes are validated and committed in a single workflow step without leaving dangling candidate changes, how can the commit parameter be handled?

Accepted Answer

Include the 'action=commit' query parameter or commit body flag with the configuration request.. The Junos REST API allows query parameters or header flags (such as '?action=commit' or dedicated commit instructions) to automatically commit changes made during a configuration modification request.

Answer

Issue an HTTP GET request to /api/configuration/commit.

Answer

Set the Transfer-Encoding header to 'commit'.

Answer

Send a separate SSH command because REST cannot commit configurations.

Question 10

When retrieving configuration data in JSON format from the Junos REST API, how are Junos hierarchical container statements represented in the JSON payload structure?

Accepted Answer

As nested JSON objects reflecting the hierarchical tree structure of the CLI configuration.. Junos configuration hierarchies are translated into nested JSON objects where each container level corresponds to a JSON key whose value is an object or an array of objects.

Answer

As comma-separated string lists inside a single root array.

Answer

As flat key-value pairs separated by dots (e.g., 'system.host-name').

Answer

As binary encoded ASN.1 objects.

Question 11

An automation developer is designing a tool that interacts with multiple network vendors, including Juniper Junos. They evaluate using Junos REST API versus NETCONF. Which workflow advantage does the REST API offer over NETCONF in web-centric application environments?

Accepted Answer

REST API leverages standard HTTP/HTTPS transport infrastructure, making it easily traversable through web proxies and adaptable to modern web frameworks using native JSON.. REST APIs natively integrate with standard HTTP load balancers, web proxies, firewalls inspectable by HTTP/HTTPS, and standard web application frameworks without needing specialized SSH tunnel management or XML parser libraries.

Answer

REST API completely replaces the Junos candidate configuration datastore with a real-time database.

Answer

REST API natively supports XML parsing, whereas NETCONF only supports binary protocols.

Answer

REST API guarantees atomic multi-device commits across different vendors without controllers.

Question 12

Which TWO characteristics are true regarding the Junos REST API? (Choose two)

Accepted Answer

It supports both JSON and XML data formats.. Option B is correct because the Junos REST API accepts and returns both JSON and XML payloads, letting clients choose the representation via the Content-Type and Accept headers (for example application/json or application/xml). Option D is correct because the REST API is served by the jpagent (Junos REST API agent) daemon, which listens on HTTPS (TCP 443) and handles REST requests on the device. Option A is wrong because the REST API is accessed over standard HTTP/HTTPS with no proprietary C++ client libraries to compile. Option C is wrong because REST is stateless and uses HTTP/HTTPS requests, not a persistent SSH session per transaction. Option E is wrong because TCP 830 is used by NETCONF over SSH, not by the REST API, which uses HTTPS on port 443.

Answer

It requires client-side compilation of proprietary C++ libraries.

Answer

It requires a persistent SSH session for every transaction.

Answer

It runs on TCP port 830 exclusively.

Question 13

Which THREE HTTP methods are commonly used within the Junos REST API for managing configuration and operational resources? (Choose three)

Accepted Answer

POST. The Junos REST API uses standard HTTP verbs to manipulate configuration and operational resources, and the three commonly supported methods are GET, POST, and DELETE. GET (C) is correct because it is used to retrieve operational data or configuration information from Junos, such as via REST endpoints that return XML or JSON representations of state and configuration. POST (B) is correct because it is used to create, modify, or execute configuration and operational requests, including loading configuration changes or invoking RPCs through the REST API. DELETE (E) is correct because it is used to remove configuration statements or resources at a specified REST endpoint. TRACE (A) is not used by the Junos REST API; it is a diagnostic HTTP method for echoing requests and is generally disabled for security. CONNECT (D) is also not part of Junos REST API resource management; it establishes a tunnel through a proxy and is unrelated to configuration or operational resource handling.

Answer

TRACE

Answer

CONNECT

Question 14

Which THREE actions can be performed using the Junos REST API operational endpoints? (Choose three)

Accepted Answer

Fetch interface packet counters and operational states.. Option B is correct because Junos REST API operational endpoints expose RPCs such as get-interface-information, which return live interface packet counters and operational states (up/down, errors, etc.) in JSON or XML. Option C is correct because operational endpoints include RPCs like get-system-information and get-chassis-inventory, which retrieve hardware and software inventory details from the device. Option E is correct because the REST API operational endpoint accepts arbitrary operational RPCs, including get-route-information, invoked via HTTP GET/POST to /rpc/get-route-information. Option A is not correct because modifying the startup configuration file on disk is a configuration-management task handled through configuration endpoints or CLI, not operational RPC endpoints. Option D is not correct because formatting and partitioning local SSDs is a low-level maintenance action not exposed through Junos REST operational RPCs.

Answer

Directly modify the startup configuration file on the hard disk.

Answer

Format and partition local storage solid-state drives.

Question 15

Which TWO error response categories or HTTP status codes are commonly returned by the Junos REST API when client requests are malformed or unauthorized? (Choose two)

Accepted Answer

401 Unauthorized. Option A (401 Unauthorized) is correct because the Junos REST API returns HTTP 401 when a client request lacks valid authentication credentials, such as a missing or incorrect Authorization header or invalid username/password, which is the standard response for unauthorized access. Option B (400 Bad Request) is correct because the Junos REST API returns HTTP 400 when the client request is malformed, for example due to invalid JSON/XML payload syntax, incorrect URI formatting, or unsupported parameters that the server cannot parse. Option C (202 Accepted) is not correct because it is a success-class status indicating the request was accepted for processing, not an error for malformed or unauthorized requests. Option D (504 Gateway Timeout) is not correct because it indicates an upstream server failed to respond in time, which is an infrastructure/proxy timeout rather than a client malformation or authorization error. Option E (100 Continue) is not correct because it is an informational interim response used with the Expect: 100-continue mechanism, not an error category returned for malformed or unauthorized requests.

Answer

202 Accepted

Answer

504 Gateway Timeout

Answer

100 Continue