JNCIA-DevOps Junos Automation Stack And DevOps Concepts Practice Test 4 — 15 Questions

Question 1

Which TWO advantages does structured telemetry and data streaming offer over traditional SNMP polling in Junos automation? (Choose two)

Accepted Answer

High granularity and real-time visibility into operational state. Option C is correct because structured telemetry and data streaming provide high granularity and real-time visibility into operational state, delivering continuous, fine-grained metrics (e.g., via gRPC or JTI) rather than the coarse, interval-based snapshots typical of SNMP polling. Option E is correct because streaming uses a push-based model where devices proactively send data to collectors, eliminating the periodic polling overhead and associated CPU, bandwidth, and latency costs of SNMP GET/WALK cycles. The unmarked options do not belong: A is wrong because Junos devices run Junos OS, not Windows Server, and telemetry does not require it; B is wrong because analog dial-up modems are obsolete and irrelevant to modern telemetry transport; D is wrong because network interfaces are still required for connectivity and telemetry transport, so they are not eliminated.

Answer

Requiring all network devices to run Windows Server OS

Answer

Mandatory requirement for analog dial-up modems

Answer

Elimination of all network interfaces

Question 2

In a Git repository managing Junos configurations, which TWO files or directories are typically added to the '.gitignore' file to prevent sensitive or temporary files from being tracked? (Choose two)

Accepted Answer

Local IDE configuration folders and temporary build output directories. Option B is correct because local IDE configuration folders (e.g., .vscode/, .idea/) and temporary build output directories contain machine-specific or generated artifacts that should never be committed to a shared Git repository. Option D is correct because files holding decrypted production passwords or private SSH keys are highly sensitive secrets that must be excluded from version control to prevent credential leakage. Option A is incorrect because Juniper's core YANG data models are vendor-supplied schema files that are typically versioned or referenced deliberately, not ignored. Option C is incorrect because Git commit history is intrinsic to the repository's object database and cannot be placed in .gitignore. Option E is incorrect because standard production Jinja2 templates are legitimate configuration source files that should be tracked and versioned.

Answer

Core YANG data models provided by Juniper

Answer

Master branch commit history logs

Answer

Standard production Jinja2 templates (.j2)

Question 3

When writing Python automation scripts for Junos using PyEZ, which THREE objects or methods are commonly used for device interaction and configuration management? (Choose three)

Accepted Answer

Config (from jnpr.junos.utils.config) to handle configuration transactions. Option E is correct because the Device class from jnpr.junos is the core PyEZ object that opens and manages the NETCONF session to a Junos device, providing the transport used by all other operations. Option C is correct because Config from jnpr.junos.utils.config wraps configuration transactions, allowing methods like load(), commit(), rollback(), and diff() to apply candidate configurations safely. Option D is correct because Fact, loaded via the factory Loader from jnpr.junos.factory.factory_Loader, retrieves structured device facts such as hardware model, Junos version, and serial number for inventory and automation logic. Option A is not part of PyEZ and is unrelated to Junos device interaction, and Option B is not a real PyEZ object or method and would be a destructive, nonsensical operation.

Answer

Microsoft_Excel_Workbook for direct spreadsheet parsing

Answer

Kernel_Panic_Trigger to deliberately crash the router

Question 4

Which TWO benefits are provided by implementing automated CI/CD pipelines for Junos network changes? (Choose two)

Accepted Answer

Standardized, repeatable validation and testing of every change before production. Option A is correct because CI/CD pipelines run standardized, repeatable validation and testing (e.g., Junos commit check, configuration linting, and automated test suites) on every proposed change before it reaches production, ensuring consistency and catching errors early. Option D is correct because automation accelerates deployment by pushing validated configurations rapidly and consistently, removing manual CLI typing and thereby reducing human configuration errors. Option B is incorrect because CI/CD automation does not eliminate routing protocols such as OSPF; those protocols remain essential for dynamic routing regardless of how changes are deployed. Option C is incorrect because automated pipelines handle software and configuration changes, not physical hardware replacement like swapping optical transceivers, which still requires human or robotic intervention outside CI/CD scope. Option E is incorrect because no pipeline can guarantee 100% uptime; fiber cuts are physical-layer failures that CI/CD cannot prevent.

Answer

Elimination of network routing protocols like OSPF

Answer

Immediate physical replacement of broken optical transceivers by robots

Answer

Guaranteed 100% uptime regardless of fiber cuts

Question 5

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. Option B is correct because NETCONF sessions are established over SSH (default TCP port 830), and the client can authenticate with a username and password just like a standard SSH login. Option C is correct because SSH public key authentication is a supported method for authenticating the NETCONF-over-SSH session, using the client's private key matched against an authorized key on the Junos device. Option A is correct because Junos can delegate authentication of NETCONF-over-SSH users to external RADIUS or TACACS+ AAA servers, so credentials are validated by the remote AAA server rather than only local accounts. Option D is wrong because NETCONF requires authenticated credentials and does not permit anonymous guest access. Option E is wrong because NETCONF uses SSH transport, not unencrypted cleartext Telnet on TCP port 23.

Answer

Anonymous guest access without credentials

Answer

Unencrypted cleartext Telnet on TCP port 23

Question 6

When executing a configuration commit in Junos via NETCONF, which TWO commit parameters or modifiers can be specified in the RPC? (Choose two)

Accepted Answer

Check-only validation (verifying syntax without activating the configuration). Option B is correct because the Junos NETCONF RPC supports the element, which performs a check-only validation of the candidate configuration — the device verifies syntax and commit-time constraints without actually activating the configuration. Option C is correct because the RPC also supports the element (optionally with a value in seconds), which activates the configuration but automatically rolls back to the previous committed configuration unless a confirming commit is issued within the timeout. Option A is wrong because packet capture on port 0 is not a commit parameter; capture is configured via firewall filter actions or the 'monitor traffic' CLI, not the NETCONF commit RPC. Option D is wrong because 'instant kernel bypass switching' is not a Junos commit modifier — it is not a real Junos feature at all. Option E is wrong because formatting a hard disk partition is an installation/disk operation, not a parameter of the NETCONF commit RPC.

Answer

Direct packet capture on port 0

Answer

Instant kernel bypass switching

Answer

Format hard disk partition primary

Question 7

Which TWO characteristics describe declarative network automation compared to imperative scripting? (Choose two)

Accepted Answer

Defining the desired end state rather than scripting exact step-by-step CLI commands. Option B is correct because declarative network automation focuses on specifying the intended end state (for example, a desired VLAN, interface, or routing configuration) rather than writing the exact sequence of CLI commands to reach it. Option E is correct because the automation engine (such as Ansible with declarative modules, Terraform, or NSO) compares the current state to the desired state and automatically computes and applies the necessary changes, including diffs and idempotent updates. Option A is incorrect because manually logging into each router and running sequential shell commands is the opposite of declarative automation and is characteristic of manual or imperative operation. Option C is incorrect because hardcoded assembly language for packet processing is unrelated to declarative network automation and describes low-level programming, not intent-based configuration. Option D is incorrect because manually calculating diff patches for every line item is a tedious imperative task, whereas declarative systems generate the required diffs automatically.

Answer

Manually logging into each router to execute sequential shell commands

Answer

Using hardcoded assembly language for packet processing

Answer

Requiring manual calculation of diff patches for every single line item

Question 8

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 9

In a Junos NETCONF automation workflow, what happens during a lock operation on the configuration database? (Choose two)

Accepted Answer

Exclusive write access is acquired for the requesting session, preventing concurrent configuration modifications by other users or scripts.. Option A is correct because a Junos operation on the candidate configuration grants the requesting NETCONF session exclusive write access, so other users, CLI sessions, or automation scripts cannot modify the configuration concurrently until the lock is released. Option C is correct because the lock is held by that session and must be explicitly released with an operation, or implicitly released when the NETCONF session closes, before other processes can edit the configuration. The unmarked options are incorrect: B is false because locking the configuration database has nothing to do with powering down a Routing Engine, D is false because operational commands like 'show route' remain available and are not disabled by a configuration lock, and E is false because no firewall filters are deleted by a lock operation.

Answer

The physical routing engine is immediately powered down to prevent hardware wear.

Answer

All operational state monitoring (such as 'show route') is permanently disabled.

Answer

All firewall filters on all interfaces are automatically deleted.

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)

Question 11

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 12

An operations team is applying DevOps principles to network automation on Junos devices. They want to ensure that all changes to device operational states and configurations are treated as disposable and repeatable. Which DevOps practice best describes rebuilding device configurations completely from centralized version-controlled templates rather than performing manual incremental hot-patches?

Accepted Answer

Immutable infrastructure and declarative provisioning. Infrastructure as Code (IaC) and immutable infrastructure treat configurations as reproducible artifacts generated from source control rather than mutable, long-lived states modified ad-hoc.

Answer

Stateful configuration drift management

Answer

Blue-green circuit provisioning

Answer

Event-driven telemetry ingestion

Question 13

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?

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 14

An enterprise network is adopting a CI/CD pipeline for Junos network changes using GitLab CI. A developer wants to ensure that a test job automatically runs whenever a merge request is opened against the main branch. In which configuration file must this pipeline behavior be defined, and what is the primary keyword used to control branch execution?

Accepted Answer

.gitlab-ci.yml, using the 'rules' or 'only' keyword. GitLab CI pipelines are defined in a .gitlab-ci.yml file located in the root of the repository, and jobs use the 'rules' or 'only/except' keywords to control execution on specific branches.

Answer

Junos 'juniper.conf', using the 'commit-script' keyword

Answer

ansible.cfg, using the 'hosts' parameter

Answer

Jenkinsfile, using the 'when' parameter

Question 15

A network architect is designing a version control strategy for multi-vendor network operations. They need a system that tracks changes to text-based configuration files, allows multiple engineers to work on separate feature branches concurrently, and merges changes systematically. Which category of tool is being utilized?

Accepted Answer

Distributed Version Control System (DVCS). Git and similar tools are Distributed Version Control Systems (DVCS) designed to track file revisions and manage collaborative workflows through branching and merging.

Answer

Network Management System (NMS) poller

Answer

Network Configuration Protocol (NETCONF) manager

Answer

Dynamic Host Configuration Protocol (DHCP) server