JNCIA-DevOps Practice Test 5 — 25 Questions

Question 1

Which TWO of the following are valid primitive data types in JSON? (Choose two)

Accepted Answer

String. JSON primitive types include strings, numbers, booleans, and null. Arrays and objects are composite types.

Answer

Function

Answer

Undefined

Answer

Symbol

Question 2

You are writing a Python automation tool that reads telemetry data from a Junos device. The data is received as a JSON string containing forward slashes escaped as '\/'. When you load this string using json.loads(), how does Python handle the escaped slashes?

Accepted Answer

They are automatically converted to unescaped forward slashes ('/').. JSON allows forward slashes to be escaped as '\/' for embedding JSON inside HTML script tags. Python's json.loads() automatically unescapes '\/' into normal '/' characters in the resulting string.

Answer

The parser raises a ValueError because escaped slashes are invalid in JSON.

Answer

They remain as literal escaped sequences ('\/').

Answer

They are converted to backslashes ('\').

Question 3

Which TWO Python standard library modules are commonly combined when a script needs to fetch web content (such as Junos REST API data) and parse the resulting payload? (Choose two)

Accepted Answer

json. The 'urllib.request' module handles HTTP requests, and the 'json' module handles parsing the resulting JSON response.

Answer

yaml

Answer

socket

Answer

pickle

Question 4

Which TWO methods are provided by the Python standard library 'json' module for deserializing JSON data? (Choose two)

Accepted Answer

json.loads(). The json module provides json.load() for file-like objects and json.loads() for strings.

Answer

json.read()

Answer

json.decode()

Answer

json.parse()

Question 5

A network engineer is using Git for version control of Junos configurations. During a peer review on a pull request, a merge conflict arises because two engineers modified the same interface description line in different branches. What is the correct procedure to resolve this conflict in Git?

Accepted Answer

Manually edit the conflict markers in the affected configuration file, stage the resolved file, and complete the merge commit.. Git marks the conflicting lines in the file, requiring manual editing to choose the correct changes or combine them, followed by staging and committing the resolution.

Answer

Reboot the Junos routing engine to clear the Git repository cache and force a fast-forward merge.

Answer

Run the 'git force-merge' command to automatically discard the older branch's changes.

Answer

Use 'git reset --hard' on the remote repository to delete both conflicting branches entirely.

Question 6

An automation engineer needs to include comments explaining complex network parameters inside a Junos automation data file. Which serialization format should the engineer select?

Accepted Answer

YAML. YAML natively supports comments using the hash (#) symbol, whereas standard JSON does not support comments.

Answer

CSV

Answer

JSON

Answer

Pickle

Question 7

An engineer needs to convert an existing YAML-formatted inventory file into JSON format using a Python script. Which workflow accomplishes this transformation?

Accepted Answer

Load YAML with yaml.safe_load() and serialize to JSON with json.dumps().. To convert YAML to JSON, the engineer must read and parse the YAML file into a Python data structure using yaml.safe_load(), and then serialize that structure into a JSON string using json.dumps().

Answer

Directly pass the YAML file object into json.load().

Answer

Rename the file extension from .yaml to .json.

Answer

Use yaml.safe_dump() directly on the JSON output stream.

Question 8

Which character is used to indicate a mapping key-value pair in YAML syntax?

Accepted Answer

Colon (:). In YAML, a key-value mapping is represented by a colon followed by a space (: ).

Answer

Semicolon (;)

Answer

Arrow (->)

Answer

Equals sign (=)

Question 9

When serializing complex nested Python dictionaries to JSON, which THREE data types will cause a TypeError unless handled by a custom default encoder function? (Choose three)

Accepted Answer

Python set objects. Standard json.dumps() cannot serialize sets, complex numbers, or custom class instances without custom encoder logic.

Answer

Standard string objects

Answer

Boolean values

Question 10

A Python automation script parses a Junos telemetry stream in JSON. The JSON payload uses integer keys in a dictionary (e.g., {443: 'HTTPS'}). When loaded into Python using json.loads(), what data type do the dictionary keys become?

Accepted Answer

They are converted to Python string objects.. JSON specification dictates that object keys must be strings. When json.loads() parses an object, any keys (even if numeric-looking) are converted to Python strings.

Answer

They are converted to floating-point numbers.

Answer

They remain integer objects.

Answer

The parser raises a KeyError because JSON keys must be alphabetic.

Question 11

An engineer needs to represent an ordered list of IP addresses in a YAML configuration file for a Junos automation playbook. Which valid YAML syntax correctly defines a sequence of items?

Accepted Answer

ip_addresses:
  - 192.168.1.1
  - 192.168.1.2. In YAML, lists or sequences are represented using a hyphen followed by a space (-) at the beginning of each line.

Answer

ip_addresses = {192.168.1.1, 192.168.1.2}

Answer

ip_addresses: [192.168.1.1: 192.168.1.2]

Answer

ip_addresses:
  * 192.168.1.1
  * 192.168.1.2

Question 12

An engineer receives a YAML configuration snippet for a PyEZ automation script, but the script fails with a parser error. Upon inspection, the error is caused by improper indentation levels. Which rule must be strictly followed regarding indentation in YAML syntax?

Accepted Answer

Spaces must be used for indentation, and tabs are strictly forbidden.. YAML requires the use of space characters for indentation. Tab characters are strictly forbidden for indentation purposes.

Answer

Indentation is completely optional if curly braces are used.

Answer

Tabs must be used consistently for every level of indentation.

Answer

Indentation must always be exactly four spaces per level.

Question 13

Which TWO Python exceptions might be raised when attempting to parse a malformed JSON string using the standard 'json' module? (Choose two)

Accepted Answer

JSONDecodeError. json.loads() raises JSONDecodeError (which inherits from ValueError) when encountering invalid JSON syntax.

Answer

AttributeError

Answer

KeyError

Answer

ScannerError

Question 14

A network engineer is establishing a version control workflow for network configurations using Git. Which Git command should the engineer use to stage newly created configuration template files in the local repository working directory so they are included in the next commit?

Accepted Answer

git add. The git add command stages changes in the working directory, moving them to the staging area (index) to prepare them for a commit.

Answer

git clone

Answer

git commit

Answer

git push

Question 15

An engineer needs to explain the primary advantage of treating network configurations as code in a modern DevOps workflow. Which principle best describes this approach?

Accepted Answer

Storing configurations in a version control system to track history, enable rollbacks, and facilitate collaboration.. Treating network configurations as code allows infrastructure to be version-controlled, repeatedly deployed, and tested just like software code.

Answer

Immutable infrastructure deployment where devices are replaced rather than updated manually.

Answer

Compiling the network CLI commands into binary machine code before executing them on Junos devices.

Answer

Automating the complete removal of the command-line interface in favor of graphical topology builders.

Question 16

You are writing a Python script using the PyEZ library to retrieve interface facts from a Juniper EX Series switch. The resulting data structure is stored in a Python dictionary. You need to dump this dictionary into a YAML file so it can be read by an Ansible playbook later. Which PyYAML function should you use to convert the Python dictionary into a YAML-formatted string or file stream?

Accepted Answer

yaml.dump(). yaml.dump() is the standard PyYAML function used to serialize Python objects (such as dictionaries) into a YAML-formatted stream or string.

Answer

yaml.load()

Answer

yaml.serialize()

Answer

yaml.safe_load()

Question 17

A network automation script is reading a YAML configuration file containing Junos device credentials. The script encounters an unhandled exception when attempting to load the file using PyYAML. Upon inspection, the error is caused by a tab character used for indentation instead of spaces. Which YAML specification rule does this violate?

Accepted Answer

Tab characters are strictly forbidden for indentation in YAML.. YAML 1.2 specifications explicitly prohibit the use of the tab character for indentation. All indentation whitespace must consist exclusively of space characters to maintain hierarchy definition.

Answer

Comments must start with a double forward slash (//).

Answer

YAML files require all keys to be wrapped in double quotes.

Answer

Top-level keys must start with a hyphen (-) character.

Question 18

An automation engineer is writing a Python script to parse a Juniper Junos NETCONF reply received in XML format and needs to convert it into a JSON structure for easier manipulation in a web application. Which built-in Python module is primarily used to handle JSON data serialization and deserialization?

Accepted Answer

json. The 'json' module is the standard built-in Python library used for parsing, serializing, and deserializing JSON data.

Answer

pickle

Answer

yaml

Answer

xml.etree

Question 19

What is the primary benefit of using structured data formats (such as XML, JSON, or YAML) over unstructured CLI text output in Junos automation?

Accepted Answer

They allow automation scripts to parse device output reliably without relying on brittle regular expressions.. Structured data formats can be easily parsed programmatically without relying on fragile regular expressions.

Answer

Structured data formats take up less memory on the Junos Routing Engine hard drive.

Answer

They eliminate the need to authenticate when connecting via NETCONF or gRPC.

Answer

They automatically convert all IPv4 addresses to IPv6 format.

Question 20

In a Junos automation environment, what role does a schema (such as YANG or Junos XSD) play when interacting with NETCONF?

Accepted Answer

It defines the structural rules, data types, and valid hierarchy for configuration and operational data models.. YANG or XSD schemas define the data model structure, types, and constraints for configuration and operational data.

Answer

It encrypts the communication channel between the client and the Junos device.

Answer

It acts as a firewall filter blocking unauthorized IP addresses on the management interface.

Answer

It compiles Python scripts into executable machine code for the Routing Engine CPU.