JNCIA-DevOps Practice Questions 1 — 50 Questions

Question 1

You are configuring a CI/CD pipeline for Junos network deployments. The pipeline must validate the syntax of generated candidate configurations against a physical or virtual Junos device before committing them to production. Which stage of the CI/CD pipeline does this validation step represent?

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

Accepted Answer

Continuous Integration validation stage. Checking syntax and logic prior to production deployment is a core part of the Continuous Integration (CI) validation and testing stage.

Answer

Continuous Deployment stage

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Continuous Monitoring stage

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Infrastructure Provisioning stage

Question 2

Which command is used in Git to save staged changes to the local repository with a descriptive commit message?

Accepted Answer

git commit -m "message". 'git commit' records changes to the local repository.

Answer

git add

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git push

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git save

Question 3

During a NETCONF session with a Junos device, an automation script issues an RPC to load a configuration. The device returns a response containing an <rpc-error> tag. What does this indicate?

Accepted Answer

The configuration or RPC request failed validation, syntax checking, or execution constraints on the device.. An <rpc-error> tag in NETCONF indicates that the request could not be processed successfully due to syntax, permission, or validation errors.

Answer

The Junos routing engine is operating at 100% CPU capacity.

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The NETCONF session has successfully terminated with a normal exit code.

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The physical optical link on the management port has failed.

Question 4

What is the primary delimiter used to separate key-value pairs in a JSON object?

Accepted Answer

Comma (,). JSON object key-value pairs are separated by commas (,).

Answer

Forward slash (/)

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Semicolon (;)

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Period (.)

Question 5

Which file extension is conventionally used for YAML data serialization files?

Accepted Answer

.yaml. YAML files typically use .yaml or .yml extensions.

Answer

.json

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.ini

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.xml

Question 6

A Python script processes a YAML configuration template for Junos BGP neighbors. The configuration contains a multi-line banner string description. Which YAML block scalar indicator preserves newlines exactly as written in the text block?

Accepted Answer

The pipe symbol (|). In YAML, the pipe symbol (|) denotes a literal scalar style, which preserves newlines within multi-line strings.

Answer

The ampersand symbol (&)

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The greater-than symbol (>)

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The asterisk symbol (*)

Question 7

What is the native data format returned by Junos devices when queried via REST API or NETCONF operations configured with JSON output formatting?

Accepted Answer

JSON. When JSON output is requested from Junos REST or NETCONF, the returned data is serialized in JSON format.

Answer

INI

Answer

YAML

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CSV

Question 8

Which TWO of the following are valid extensions commonly used for YAML files? (Choose two)

Accepted Answer

.yaml. YAML files commonly use either .yaml or .yml file extensions.

Answer

.xml

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.jsn

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.txt

Question 9

An automation engineer is designing a deployment strategy for Junos devices using Git branches. Which branching strategy model aligns best with continuous delivery where feature branches are merged frequently into a shared integration branch that automatically triggers staging tests?

Accepted Answer

Trunk-based development where developers merge small, frequent changes into a central main branch that drives automated pipelines.. GitFlow and trunk-based development describe common branching models; trunk-based development or short-lived feature branches with continuous integration are standard for modern DevOps.

Answer

Creating a separate permanent branch for every physical router in the network and never merging them.

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Locking the master branch for 12 months while developing a single monolithic configuration update offline.

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Using tag-based releases exclusively without utilizing any version control branches.

Question 10

Which symbol represents the beginning of a single YAML document stream?

Accepted Answer

Three dashes (---). YAML documents can optionally begin with a document start marker consisting of three dashes (---).

Answer

Three hashes (###)

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Three slashes (///)

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Three dots (...)

Question 11

An automation engineer needs to pretty-print a JSON payload in the Linux terminal for debugging Junos telemetry. Which built-in Python command-line utility can be invoked to validate and pretty-print a JSON file?

Accepted Answer

python3 -m json.tool filename.json. Python provides a command-line JSON tool via the json.tool module, invoked as 'python3 -m json.tool filename.json'.

Answer

python3 -m yaml.format filename.json

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python3 -c 'import json; json.format()'

Answer

netconf-console --pretty filename.json

Question 12

Which TWO file formats are commonly used for structuring network configuration data and automation templates in Junos DevOps pipelines? (Choose two)

Accepted Answer

JSON. YAML and JSON are standard data serialization formats used alongside Jinja2 templates.

Answer

Proprietary binary core dump format

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Raw bitmap image (.bmp) format

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Windows executable (.exe) format

Question 13

When parsing a Junos configuration snippet in YAML, an engineer notices a string value starting with a zero (e.g., '01234') that is unquoted. How do YAML parsers typically interpret this value?

Accepted Answer

As an octal integer.. In YAML 1.1, numbers starting with a leading zero are interpreted as octal (base 8) integers. To ensure it is treated as a string, it must be quoted.

Answer

The parser throws a ScannerError due to invalid numeric formatting.

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As a string literal matching the exact characters.

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As a floating-point number with zero prefix.

Question 14

Which of the following valid JSON values represents a boolean true state?

Accepted Answer

true. JSON booleans are lowercase words: true and false.

Answer

True

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"true"

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TRUE

Question 15

An automation developer is designing a script that reads routing policy parameters from a configuration file. Which TWO data formats are natively supported and commonly used across Junos automation toolchains like PyEZ, Ansible, and REST APIs for data serialization? (Choose two)

Accepted Answer

YAML. JSON and YAML are the primary lightweight data serialization formats universally utilized across modern network automation toolchains and APIs.

Answer

BMP

Answer

RTF

Answer

EXE

Question 16

In Git version control, which TWO commands are used to integrate changes from one branch into another? (Choose two)

Accepted Answer

git merge. Git uses 'merge' and 'rebase' to integrate changes between branches.

Answer

git init

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git status

Answer

git clone

Question 17

Which THREE mechanisms are valid methods for authenticating and establishing a NETCONF session with a Junos device? (Choose three)

Accepted Answer

Remote RADIUS or TACACS+ AAA server integration via SSH transport. NETCONF on Junos runs over SSH, supporting SSH keys, username/password, and AAA integration.

Answer

Anonymous guest access without credentials

Answer

Unencrypted cleartext Telnet on TCP port 23

Question 18

You are writing a Python automation script that reads a Junos configuration file in JSON format. The JSON file contains duplicate keys within the same object scope. According to the JSON specification RFC 8259, how should a conforming JSON parser handle duplicate keys?

Accepted Answer

Behavior is undefined by the specification; typically the last defined key-value pair overwrites previous ones in Python dictionaries.. RFC 8259 states that while names within an object SHOULD be unique, the specification does not mandate how parsers should handle duplicates, resulting in behavior dependent on the parser (typically keeping the last encountered key-value pair).

Answer

Both values are automatically combined into a JSON array under that key.

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Duplicate keys are prohibited, and compliance checks will reject the file pre-parsing.

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The parser must raise a fatal JSONDecodeError immediately.

Question 19

An automation engineer needs to convert a JSON payload representing Junos interface configurations into equivalent YAML format to reuse in an Ansible playbook. Which fundamental structural relationship between JSON and YAML makes this conversion straightforward?

Accepted Answer

YAML is a strict superset of JSON, allowing valid JSON to be parsed as YAML.. YAML is a superset of JSON, meaning any valid JSON document is technically also a valid YAML document, allowing direct mapping of data structures.

Answer

JSON uses indentation for structure just like YAML.

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JSON and YAML both strictly require curly braces for all data containers.

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YAML forces all numeric values to be encapsulated in strings.

Question 20

When converting a deeply nested JSON data structure representing Junos device health metrics into YAML using PyYAML, the output uses complex block styles that are difficult for team members to read. Which parameter in yaml.safe_dump() can force scalar values or containers to prefer flow style (JSON-like curly braces and brackets) instead?

Accepted Answer

default_flow_style=True. The default_flow_style parameter in yaml.safe_dump() controls how collections are dumped. Setting default_flow_style=False uses block style, while True or None dictates flow style formatting.

Answer

force_json=True

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format='compact'

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style='flow'