JNCIA-DevOps Practice Test 9 — 10 Questions

Question 1

You are writing a script that performs multiple configuration changes inside a single PyEZ Config context. How can you verify that the candidate configuration has syntax errors before committing it?

Accepted Answer

cu.validate(). The .validate() method checks the candidate configuration for syntax and semantic errors without committing.

Answer

cu.test_syntax()

Answer

cu.verify()

Answer

cu.check()

Question 2

When using Jinja2 inheritance, which tag is placed in a base template to indicate where child templates can insert their custom content?

Accepted Answer

{% block block_name %} ... {% endblock %}. The block tag defines regions that child templates can override.

Answer

Answer

{% insert block_name %}

Answer

{% child_content %}

Question 3

Which of the following data types is natively supported in JSON without requiring custom serialization handlers?

Accepted Answer

Boolean. JSON natively supports strings, numbers, booleans, null, arrays, and objects (dictionaries with string keys). Python tuples or sets are not natively supported.

Answer

Python set

Answer

Complex number

Answer

Python tuple

Question 4

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 native Python dictionary for internal processing. Which built-in library should the engineer use to convert the structured XML tree?

Accepted Answer

xml.etree.ElementTree. xml.etree.ElementTree is a standard Python library used for parsing and navigating XML data structures. While JSON and YAML are common serialization formats, NETCONF protocol responses natively return XML, which must be parsed before data manipulation.

Answer

pickle

Answer

yaml

Answer

json

Question 5

An automation engineer is writing a Python script that takes a complex nested Python dictionary containing Junos telemetry parameters and converts it into a YAML string. Which PyYAML function should be used?

Accepted Answer

yaml.safe_dump(). yaml.safe_dump() converts a Python object into a YAML-formatted string safely, avoiding the security risks associated with the base yaml.dump().

Answer

yaml.export()

Answer

yaml.serialize_string()

Answer

yaml.to_yaml()

Question 6

You are writing a Python script that parses a multi-document YAML stream containing Junos device site configurations. One of the documents contains a custom YAML tag. When parsing with yaml.safe_load_all(), how does the safe loader handle custom tags?

Accepted Answer

It raises a ConstructorError unless a custom constructor is registered.. The safe loader in PyYAML does not know how to construct objects from custom tags by default and will raise a ConstructorError unless a custom constructor has been explicitly registered.

Answer

It converts the tagged object into a JSON equivalent.

Answer

It automatically evaluates the custom tag using Python eval().

Answer

It ignores the tag and loads the scalar value as a plain string.

Question 7

An automation script reads a multi-document YAML file containing configuration templates for various Junos router models. To process each document individually in Python using PyYAML, which function should the engineer invoke?

Accepted Answer

yaml.safe_load_all(). yaml.safe_load_all() is designed to parse a stream containing multiple YAML documents separated by '---', returning a generator that yields each parsed document sequentially.

Answer

yaml.read_multi()

Answer

yaml.load_all()

Answer

yaml.parse_documents()

Question 8

Which of the following characters is used to start a comment line in a YAML document?

Accepted Answer

Hash sign (#). Comments in YAML begin with the hash or pound sign (#) and continue to the end of the line.

Answer

Exclamation mark (!)

Answer

Percent sign (%)

Answer

Double forward slash (//)

Question 9

An automation engineer is reviewing data serialization formats used within Junos automation workflows. Which TWO statements are correct regarding JSON syntax and data types? (Choose two)

Accepted Answer

JSON object keys must be enclosed in double quotes.. JSON object keys must always be double-quoted strings, and null is a valid scalar value representing an empty or missing value.

Answer

Single quotes can be used interchangeably with double quotes for strings.

Answer

JSON supports inline comments starting with the '#' symbol.

Answer

Trailing commas are permitted in both arrays and objects.

Question 10

An automation engineer wants to log structured data from a Junos device automation run. The Python script formats a dictionary into a JSON string and prints it. However, the engineer wants all keys sorted alphabetically to ensure consistent log diffing. Which parameter accomplishes this in json.dumps()?

Accepted Answer

sort_keys=True. The sort_keys parameter in json.dumps() sorts the output of dictionaries by key alphabetically.

Answer

keys_sort=True

Answer

alphabetize=True

Answer

order='alphabetical'