JNCIA-DevOps Practice Test 5 — 10 Questions

Question 1

A network automation engineer is writing a Python script using the Junos PyEZ library to retrieve operational state from a QFX Series switch. The script needs to retrieve interface statistics using an RPC instead of raw CLI text parsing. Which PyEZ method should the engineer execute to invoke the 'get-interface-information' RPC and receive the structured XML response?

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

Accepted Answer

dev.rpc.get_interface_information(). In Junos PyEZ, the dev.rpc() method is used to execute native Junos XML RPCs directly against the device and return the results as an ElementTree XML object.

Answer

dev.get_config(format='xml')

Answer

dev.load(action='set', format='xml')

Answer

dev.execute_cli('show interfaces')

Question 2

A network automation engineer is using a Python script with the PyYAML library to load a YAML file that defines a Junos device's configuration. The script needs to ensure that the loaded data is a Python dictionary and that no arbitrary Python objects are instantiated during parsing. Which function should the engineer use to safely load the YAML content?

Accepted Answer

yaml.safe_load(stream). Using yaml.safe_load ensures that only standard Python data types are constructed from the YAML input. It prevents the instantiation of arbitrary objects and mitigates security risks such as code execution. This is the recommended approach for parsing configuration files in automation scripts.

Answer

yaml.load(stream, Loader=yaml.FullLoader)

Answer

yaml.load(stream, Loader=yaml.BaseLoader)

Answer

yaml.load(stream, Loader=yaml.UnsafeLoader)

Question 3

You are writing a Python script using PyEZ to retrieve and process operational data from a Junos device. Which TWO statements correctly describe the use of PyEZ Table and View for parsing operational data? (Choose two.)

Accepted Answer

A View defines how to extract specific fields from the XML response of an RPC.. A View defines the extraction of fields from XML, and a Table uses that View to parse RPC output into a list of dictionaries. The other statements are incorrect: Tables do not auto-convert to JSON, Views can be in Python, and Tables are for operational data.

Answer

Views must be defined in a separate YAML file and cannot be coded in Python.

Answer

Tables automatically convert all XML responses into JSON format.

Answer

Tables can only retrieve configuration data, not operational data.

Question 4

An automation engineer writes a Python script that reads a Junos configuration file serialized in JSON. The file opens successfully, but parsing fails with a JSONDecodeError due to trailing commas at the end of object lists. How does standard JSON handle trailing commas compared to YAML?

Accepted Answer

JSON strictly forbids trailing commas, whereas YAML permits them in collections.. Standard JSON strictly prohibits trailing commas in objects and arrays, whereas YAML is much more lenient and allows trailing commas in sequences and mappings.

Answer

Both formats handle trailing commas identically by ignoring them.

Answer

JSON allows trailing commas, but YAML strictly forbids them.

Answer

Both JSON and YAML strictly require trailing commas for every key.

Question 5

Which THREE tasks are typical responsibilities of a network DevOps engineer managing a Junos infrastructure? (Choose three)

Accepted Answer

Writing and maintaining Python automation scripts and Jinja2 templates. Option B is correct because a network DevOps engineer on Junos infrastructure typically writes Python automation scripts using libraries such as PyEZ and ncclient, and generates configuration from Jinja2 templates to push via NETCONF or Junos CLI, which is core to infrastructure-as-code. Option C is correct because managing Git repositories, branch policies, and pull request workflows is essential for version-controlling Junos configurations and enabling peer review and rollback. Option D is correct because configuring and maintaining CI/CD pipeline tools like GitLab CI or GitHub Actions automates validation, testing, and deployment of Junos configuration changes. Option A is not a DevOps responsibility since crimping CAT6 cables is a physical layer cabling task performed by cabling technicians, not automation engineers. Option E is not a DevOps responsibility because manually rebooting every switch daily is an operational anti-pattern that automation and proper monitoring would replace.

Answer

Manually crimping CAT6 Ethernet cables in the wiring closet

Answer

Manually rebooting every switch in the data center daily

Question 6

Which python module is part of the standard library that can be used to parse XML responses returned by NETCONF?

Accepted Answer

xml.etree.ElementTree. Python's built-in xml.etree.ElementTree module provides tools for parsing and navigating XML data.

Answer

netconf.parser

Answer

xml2dict

Answer

json

Question 7

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 8

A network engineer is establishing a NETCONF session with a Junos device and needs to lock the candidate configuration to prevent concurrent modifications by other administrators. Which NETCONF operation should be executed?

Accepted Answer

. The operation allows a client to lock the configuration datastore of a device to prevent unauthorized or conflicting changes during a transaction.

Answer

<lock-config><database>candidate</database></lock-config>

Answer

<get-config><source><candidate/></source><lock/></get-config>

Answer

<edit-config><target><candidate/></target><operation>lock</operation></edit-config>

Question 9

An engineer applies a configuration change using NETCONF with <edit-config> and specifies default-operation="replace" at the top level, but includes an element with operation="merge". How does Junos evaluate this?

Accepted Answer

The specific element operation ('merge') takes precedence over the transaction-level default-operation ('replace').. Per-element operation attributes override the default-operation specified at the transaction level.

Answer

The transaction fails because default-operation and element operations conflict.

Answer

The device rolls back the configuration due to ambiguous parameters.

Answer

The default-operation takes precedence, ignoring the merge attribute.

Question 10

An automation engineer is designing a Junos network automation workflow and needs to select the component of the Junos automation architecture responsible for parsing XML and JSONRPC client requests and interacting directly with the Junos kernel and daemons. Which component fulfills this role?

Accepted Answer

mgd (Management Daemon). MGD (Management Daemon) is the primary user interface handler in Junos OS. It processes CLI commands, Netconf XML requests, and JSON-RPC APIs, translating them into operations interacting with the Junos kernel and individual routing daemons via RRDS.

Answer

jails

Answer

rpd (Routing Protocol Daemon)

Answer

jsd (Junos Script Daemon)