JNCIA-DevOps Practice Test 8 — 10 Questions

Question 1

When designing a version control workflow for Junos configurations using Git, which THREE practices are considered industry best standards? (Choose three)

Accepted Answer

Using feature branches for developing new configuration changes before merging into main. Option B is correct because feature branches isolate new Junos configuration changes from the main branch, allowing development and validation without destabilizing production-ready configurations before a controlled merge. Option D is correct because peer reviews and pull request approvals enforce a four-eyes principle, catching errors, policy violations, or unintended commit/rollback commands before changes reach the main branch. Option E is correct because semantic or descriptive commit messages document the intent of each configuration update, which is essential for audit trails, troubleshooting, and correlating commits with change tickets in Junos automation workflows. Option A does not belong because bypassing automated testing removes validation of syntax, commit checks, and rollback safety, increasing outage risk. Option C does not belong because storing plaintext administrative passwords in public Git repositories exposes credentials and violates security best practices; secrets should be managed with tools like Ansible Vault, HashiCorp Vault, or Junos encrypted passwords.

Answer

Completely bypassing automated testing to speed up deployments

Answer

Storing plaintext administrative passwords directly in public Git repositories

Question 2

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

Accepted Answer

git merge. git merge (B) is correct because it integrates changes from one branch into another by combining their commit histories, typically creating a merge commit when the target branch has diverged. git rebase (E) is also correct because it integrates changes by replaying commits from one branch onto another, producing a linear history. git init (A) only initializes a new repository and does not integrate branch changes. git status (C) merely reports working tree and staging state without modifying history. git clone (D) copies a remote repository locally but does not merge or rebase branches.

Answer

git init

Answer

git status

Answer

git clone

Question 3

A Python script retrieves interface statistics from a Junos device in JSON format, modifies a threshold value, and needs to output it back into a formatted JSON string with an indentation level of 4 spaces for readability. Which Python snippet achieves this?

Accepted Answer

json.dumps(data, indent=4). The json.dumps() method accepts an 'indent' parameter which specifies the number of spaces to use for pretty-printing the resulting JSON string.

Answer

json.format(data, spacing=4)

Answer

json.dump(data, indent=4)

Answer

json.stringify(data, spaces=4)

Question 4

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 5

You are writing a Python automation script that processes JSON output from a Junos device's 'show interfaces' operational command via PyEZ. One of the interface descriptions contains raw control characters. When the script attempts to dump this data to a JSON string using json.dumps(), it raises a ValueError. Which parameter should you pass to json.dumps() to handle non-printable or out-of-range character encoding gracefully?

Accepted Answer

ensure_ascii=False. The json.dumps() function in Python includes an 'ensure_ascii' parameter. When set to False, it allows non-ASCII characters to be emitted directly without raising serialization errors or escaping them into Unicode escape sequences.

Answer

skipkeys=True

Answer

check_circular=False

Answer

allow_nan=True

Question 6

A network engineer writes a Python script using Junos PyEZ to push a configuration change. The script uses the ConfigTable or Config class. What mechanism does PyEZ use under the hood to ensure the configuration lock is released even if the script encounters an unhandled exception?

Accepted Answer

Python context managers ('with' statements) that automatically release locks and clean up session state upon exit.. Python context managers (using the 'with' statement) automatically handle acquiring and releasing locks and rolling back candidate changes on exception in PyEZ.

Answer

NETCONF keepalive timers that drop the SSH session after 1 second.

Answer

A UNIX cron job that reboots the router every 5 minutes.

Answer

Hardware watchdog timers built into the Routing Engine ASIC.

Question 7

When managing Junos configuration changes in a team environment, why is atomic configuration rollback capability crucial during automated deployments?

Accepted Answer

It ensures that either all configuration statements in a transaction are applied successfully or none are, preventing partial/corrupt states.. Atomic rollbacks ensure that if a change set fails validation or causes a network fault, the system can revert cleanly to the previous working state without partial application.

Answer

It compresses the configuration database to save NVRAM storage space.

Answer

It allows the router to dynamically rewrite Python scripts into C++ for faster execution.

Answer

It automatically backs up the entire Junos OS image to an external TFTP server.

Question 8

Which NETCONF RPC tag is used to gracefully terminate an active NETCONF session with a Junos device?

Accepted Answer

. The RPC requests graceful termination of the NETCONF session.

Answer

<terminate-session>

Answer

Answer

<kill-session>

Question 9

What is the role of the <rpc> element in a NETCONF message exchange?

Accepted Answer

It acts as a wrapper enclosing the specific NETCONF method request sent by the client to the server.. The <rpc> element is the protocol envelope used by the client to send a request to the NETCONF server.

Answer

It defines the security credentials for SSH authentication.

Answer

It stores error logs returned by the Junos routing engine.

Answer

It terminates the NETCONF session upon completion.

Question 10

What is the standard IETF RFC that defines the core NETCONF protocol architecture and operations?

Accepted Answer

RFC 6241. RFC 6241 is the definitive IETF standard defining the NETCONF Configuration Protocol.

Answer

RFC 8040

Answer

RFC 4253

Answer

RFC 7950