JN0-223 Juniper Automation and DevOps Associate (JNCIA-DevOps) Free Practice Exam Questions (2025 Updated)

Python follows a specific execution flow when a script is run:

The code is interpreted:Python is an interpreted language, meaning that the Python interpreter reads the code line by line. When a Python script is executed, the interpreter first reads the source code.

The code is translated to bytecode:After interpreting the source code, Python translates it intobytecode. Bytecode is an intermediate representation of the source code that is portable and efficient for execution by the Python Virtual Machine (PVM).

The bytecode is executed in runtime:Finally, thePython Virtual Machine (PVM)executes the bytecode. The PVM is a part of the Python runtime environment, responsible for interpreting the bytecode into machine-specific instructions for execution.

Hence, the correct sequence is:interpreted → translated to bytecode → bytecode executed in runtime.

Why the Other Options Are Incorrect:

Options A, C, and D present an incorrect order of the script execution process, especially in how bytecode is generated and executed.

References:

Python’s documentation on the interpreter and its execution model explains this standard process.

In Python, lists are zero-indexed, meaning the first element of the list is at index 0. The given script is:

pythona = [1, 2, 3, 4, 5, 6, 7, 8, 9]

print(a[0])

a[0]refers to the first element in the lista, which is1.

So, the output of theprint(a[0])command is1.

Option A is correct because Python indexing starts at 0, making the first element of the list at index 0.

Python Official Documentation: Covers list indexing and operations.

Python Programming Tutorials: Provide examples of list indexing.

References:

In Python, the correct syntax to prompt the user for input and store that input in a variable is:

input(prompt): Theinput()function is used to take input from the user. The string provided as an argument (inside the parentheses) is displayed as a prompt to the user. The input provided by the user is returned as a string and can be stored in a variable.

Example:

hostIP = input("Device IP address: ")

In this example,"Device IP address: "is the prompt displayed to the user, and the user's input will be stored in the variablehostIP.

Options B, C, and D are syntactically incorrect in Python.

Python Official Documentation: Describes the use of theinput()function for getting user input.

Python Tutorials: Various tutorials demonstrate how to properly use theinput()function in scripts.

References:

In Junos, theJET (Junos Extension Toolkit)API supports direct modification of theEphemeral database. The Ephemeral database is a temporary configuration database used in Junos OS, allowing for changes that do not persist after a reboot unless explicitly committed to the permanent configuration.

JET API: Allows for high-performance interactions with Junos, including the ability to make changes to the Ephemeral database, which is useful for temporary configurations, dynamic policies, and other operational tasks.

Other options like WebSocket, SOAP, and REST do not provide direct access to the Ephemeral database in Junos.

Juniper Networks JET Documentation: Details how JET API interacts with the Ephemeral database.

Junos Automation and DevOps Documentation: Discusses the use of JET for automation and dynamic configuration.

References:

Juniper Networks' Junos operating system supports several APIs for on-box scripting, two of which are:

JET (Juniper Extension Toolkit): JET is a modern API framework that provides a programmable interface for interacting with Junos. It allows developers to create custom applications that run directly on Junos devices, enabling the automation of network operations. JET provides both a gRPC and a REST API interface, allowing for flexible integration with external systems.

XML API: The Junos XML API allows direct interaction with the Junos OS through XML-based requests. This API can be used to retrieve information, configure devices, and execute commands on Junos devices. The XML API is crucial for automation tasks as it provides a structured and consistent way to interact with the device's configuration and operational data.

JET (A)provides high-performance access to Junos routing, switching, and service elements via programmable interfaces. It is highly used for creating custom applications that require tight integration with the Junos OS.

XML (C), on the other hand, is a well-established method for interacting with Junos, especially for legacy systems or when working within environments where XML is the standard data format.

Detailed Explanation:Other options like Puppet (B) and Chef (D) are not APIs provided by Junos for on-box scripting but are configuration management tools used externally to manage Junos devices.

Juniper Networks JET Documentation: Provides details on how to leverage JET APIs for automation.

Junos XML Management Protocol Guide: Describes how to use XML for scripting and automating tasks in Junos.

References:These APIs are key components of Juniper's automation strategy, allowing for scalable, flexible, and efficient network operations.

In Junos PyEZ, theConfigobject provides various methods for interacting with device configurations. Two of the key methods are:

lock():This method locks the candidate configuration database to prevent other users or processes from making changes while you are modifying the configuration.

config():This method is used to create aConfigobject that represents the configuration database, allowing you to load, modify, and commit configuration changes.

Option C (lock)andOption D (config)are correct because they are valid methods provided by the PyEZConfigobject.

Option A (commie)andOption B (device)are incorrect as they are not methods of theConfigobject.

Supporting References:

Junos PyEZ Documentation:Details the methods available in theConfigobject, includinglock()andconfig().

Juniper Networks supports NETCONF libraries for several programming languages, including:

Python (B): Python has a well-supported NETCONF library calledncclient, which is widely used for automating network configurations across Junos devices.

Go (C): Go also has a NETCONF library (go-netconf), which provides similar functionalities for managing Junos devices.

Ruby (A)andSLAX (D)do not have widely recognized or supported NETCONF libraries directly from Juniper Networks, making Python and Go the correct choices.

Juniper Networks NETCONF Documentation: Lists supported programming languages and libraries for interacting with NETCONF on Junos devices.

ncclientDocumentation: The primary Python library for working with NETCONF.

References:

 A. It supports data in CSV format:The Junos REST API supports multiple data formats for transferring information between systems, including XML, JSON, andCSV (Comma Separated Values). This flexibility allows for easier data parsing, especially in environments where structured data (likeCSV) is a standard. CSV is often used for bulk data export or import and reporting purposes, making it an essential format for automation tasks involving external systems or large datasets.

Example Usage in REST API:When using the Junos REST API, a user can request configuration or operational data and specify the response format (XML, JSON, or CSV). CSV is particularly useful when integrating Junos devices with systems that require easily readable, tabular formats.

Aneventscript is used to automate responses to system events in Junos, such as an interface going down. These scripts are triggered automatically when a specified event occurs, making them suitable for tasks like monitoring interface status and executing actions when the status changes.

Option B (event)is correct because event scripts are designed for reacting to system events like an interface going down.

Option A (commit)is used for configuration changes,Option C (operation)is used for operational tasks, andOption D (SNMP)is not applicable in this context.

Supporting References:

Juniper Networks Event Scripts Documentation:Details how event scripts are used to automate responses to specific system events in Junos

The NETCONF protocol, used for network management, utilizes XML for encoding the RPC (Remote Procedure Call) requests and responses. XML is chosen because of its flexibility and ability to represent hierarchical data structures, making it well-suited for representing network configurations and states.

Option Bis correct because XML is the standard format used for NETCONF RPC payloads.

Options A (YAML), C (JSON), and D (HTML)are incorrect because these formats are not used by NETCONF for its RPC payloads.

Supporting References:

RFC 6241 - NETCONF Protocol:This RFC describes the use of XML for encoding NETCONF messages.

Aneventscript is used to automate responses to system events in Junos, such as an interface going down. These scripts are triggered automatically when a specified event occurs, making them suitable for tasks like monitoring interface status and executing actions when the status changes.

Option B (event)is correct because event scripts are designed for reacting to system events like an interface going down.

Option A (commit)is used for configuration changes,Option C (operation)is used for operational tasks, andOption D (SNMP)is not applicable in this context.

Supporting References:

Juniper Networks Event Scripts Documentation:Details how event scripts are used to automate responses to specific system events in Junos

In Python, to create a list, you use square brackets[]. The correct syntax to create a list containing the numbers 0 through 5 is:

L = [0, 1, 2, 3, 4, 5]

This statement creates a list object that stores the specified integers.

Other options are incorrect:

Adefines a string, not a list.

Bdefines a set, which is an unordered collection with no duplicate elements.

Ddefines a tuple, which is an immutable sequence, not a list.

Python Official Documentation: Discusses lists, sets, tuples, and their syntaxes.

Python Data Structures Guide: Provides examples of creating and manipulating lists.

References: