307 questions total · 5pages · All types, answers revealed
Which TWO file formats are commonly used for structuring network configuration data and automation templates in Junos DevOps pipelines? (Choose two)
Correct. JSON is widely used for structured data exchange.
Why this answer
YAML and JSON are standard data serialization formats used alongside Jinja2 templates.
An engineer writes a Python script that loads a JSON configuration file using the json.load() method. The file contains configuration parameters for a Junos device. If the JSON file contains a trailing comma at the end of the last element in an array, what will happen when the script executes?
Trailing commas violate standard JSON syntax rules, causing the parser to fail with a decode error.
Why this answer
Standard JSON specification is strict and does not allow trailing commas. Attempting to parse it will raise a json.decoder.JSONDecodeError.
When comparing NETCONF and the Junos REST API workflows, which statement accurately describes how configuration locks are handled?
NETCONF clients must manage locks explicitly, whereas REST APIs handle database access sessions internally per transaction.
Why this answer
NETCONF explicitly requires lock and unlock operations on configuration datastores (candidate/running). The Junos REST API abstracts state management or handles implicit locking depending on the specific API call, whereas NETCONF leaves lock management entirely to the client's explicit RPC control.
You are writing a Python script that converts a Junos operational state output from XML (via NETCONF) into JSON. The XML structure contains sibling elements with the same tag name. When converted naively, how do standard XML-to-JSON conversion libraries (like xmltodict) typically represent these repeated sibling elements in the resulting JSON dictionary?
Correct. Sibling elements with identical tags are aggregated into a JSON array.
Why this answer
Conversion libraries like xmltodict represent repeated sibling XML elements as a JSON array (list) to preserve all instances under a single key.
An engineer wants to inspect the differences between two committed configurations on a Junos device using the CLI or automation tools. Which operation does this correspond to in Junos configuration management?
Correct. Configuration comparison allows auditing differences between revisions.
Why this answer
Comparing configuration revisions is done using comparison features (e.g., 'show configuration | compare').
In a Junos automation environment, what role does a schema (such as YANG or Junos XSD) play when interacting with NETCONF?
Correct. Schemas define the valid structure of XML/JSON data.
Why this answer
YANG or XSD schemas define the data model structure, types, and constraints for configuration and operational data.
What is the role of the <rpc> element in a NETCONF message exchange?
The <rpc> element encapsulates every request sent by a NETCONF client.
Why this answer
The <rpc> element is the protocol envelope used by the client to send a request to the NETCONF server.
Which command or tool on a Junos device verifies that the NETCONF subsystem is enabled and listening for SSH connections?
This command verifies the NETCONF SSH service configuration status.
Why this answer
NETCONF over SSH runs as a subsystem on Junos and can be verified via system services configuration or operational commands.
You are writing a script that uses Jinja2 to dynamically render a Junos interface configuration. Which Python module and function are required to load a template from the local filesystem and render it with a dictionary of variables?
FileSystemLoader and Environment are the standard classes used to load and render templates from files.
Why this answer
Jinja2 utilizes a FileSystemLoader to find templates on disk and an Environment to manage them, allowing you to get_template() and render() with context variables.
While executing a NETCONF edit-config operation, you want to ensure that any syntax errors or invalid statements immediately cause the device to roll back the entire transaction without applying partial changes. Which parameter achieves this?
'rollback-on-error' ensures atomicity by rolling back changes if an error is encountered.
Why this answer
The error-option element with the value 'rollback-on-error' instructs the device to abort and roll back if any error occurs.
Multi-instance list entries map to JSON arrays.
You are using the PyEZ SW utility to install a new Junos image on a device. Which method parameter allows the script to automatically reboot the device after a successful installation?
Correct. Passing reboot=True to the sw.upgrade() method triggers a device reload upon completion.
Why this answer
The val parameter or reboot=True flag is typically used depending on the specific SW.upgrade() call signature. Specifically, reboot=True forces the reload.
Which TWO methods are provided by the Python standard library 'json' module for deserializing JSON data? (Choose two)
Correct. json.loads() deserializes JSON from a string.
Why this answer
The json module provides json.load() for file-like objects and json.loads() for strings.
Which TWO methods or attributes are valid when using the PyEZ SW utility to manage Junos software? (Choose two)
Correct. install is a valid SW method.
Why this answer
SW utility methods include install, upgrade, and checking device readiness.
You need to write a Python script that extracts interface status from a Junos device using PyEZ and converts the XML output directly into a Python dictionary. Which utility or function can assist with this conversion?
Correct. PyEZ Table/View mapping structures automatically parse XML output into clean Python dictionaries and lists.
Why this answer
The XMLtoPy function from jnpr.junos.factory or standard table/view mappings helps convert XML to Python data structures.
A network engineer is using Git for version control of Junos configurations. During a peer review on a pull request, a merge conflict arises because two engineers modified the same interface description line in different branches. What is the correct procedure to resolve this conflict in Git?
Correct. Merge conflicts require manual intervention using conflict markers (<<<<, ====, >>>>), then staging and committing.
Why this answer
Git marks the conflicting lines in the file, requiring manual editing to choose the correct changes or combine them, followed by staging and committing the resolution.
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?
Correct. Leading zeros in YAML 1.1 trigger octal integer interpretation.
Why this answer
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.
The 'Authorization' header is standard for passing Basic Authentication credentials in HTTP requests.
Why this answer
HTTP Basic Authentication requires the 'Authorization' header containing the keyword 'Basic' followed by the Base64-encoded username:password string.
What is the primary benefit of decoupling network configuration data (YAML/JSON) from presentation templates (Jinja2) in network automation?
Correct. Data/template separation allows reuse and simplifies updates.
Why this answer
Separating data from templates allows the same template to be reused across multiple devices with different data sets, adhering to DRY principles.
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?
Correct. PyEZ configuration context managers ensure proper cleanup and lock release.
Why this answer
Python context managers (using the 'with' statement) automatically handle acquiring and releasing locks and rolling back candidate changes on exception in PyEZ.
Which TWO of the following are valid ways to instantiate a PyEZ Device object in Python, providing connection parameters? (Choose two)
Correct. Explicit keyword arguments are standard for initializing a Device.
Why this answer
PyEZ Device can take explicit keyword arguments or read from configuration files/environment variables.
Which Junos automation toolset relies heavily on XML over NETCONF and provides robust Python libraries tailored specifically for Junos network devices?
Correct. PyEZ is Juniper's Python library for Junos automation.
Why this answer
Junos PyEZ is the Python library tailored specifically for Junos devices using NETCONF.
An automation engineer wants to retrieve information about all software packages installed on a Junos device using the REST API. Which operational RPC endpoint category is typically targeted?
This operational RPC endpoint executes the get-software-information query.
Why this answer
Software inventory and package information can be retrieved by invoking the 'get-software-information' RPC via the operational RPC URI path.
Which TWO data serialization formats can an automation engineer request using the 'Accept' header in a Junos REST API GET request? (Choose two)
Clients can request JSON responses using application/json.
An administrator issues a NETCONF <get-config> request targeting the candidate datastore and includes a namespace prefix that does not match the device's loaded YANG/XML schema namespace. How does Junos respond?
Incorrect namespaces trigger parsing or validation errors returned in an <rpc-error>.
Why this answer
Mismatched or unknown namespaces in NETCONF requests result in a malformed message or invalid-element rpc-error.
An automation engineer is trying to retrieve operational data from a Junos device using the REST API. They send an HTTP GET request to the URI path 'http://192.168.1.1:3000/api/font/operational/system/information', but the request fails with a 404 Not Found error. What is the cause of this failure?
The correct operational API route uses '/api/operational/system/information', and 'font' is an incorrect path segment.
Why this answer
The correct base path for Junos REST API operational data uses 'rpc' or 'initial' or specific resource endpoints like /api/restful/rit/rpc, but the standard path prefix for RPCs and operational data via the Junos REST API begins with /api/operational/ rather than /api/font/operational/.
Which TWO characteristics distinguish the Junos REST API from NETCONF when interacting with Junos devices? (Choose two)
REST operates over HTTP/HTTPS using standard CRUD verbs.
An administrator wants to disable the Junos REST API daemon entirely. Which CLI command achieves this?
Deleting the jpagent service configuration stops the REST API daemon.
Why this answer
To disable the jpagent service, the administrator uses the 'delete system services jpagent' command in configuration mode.
Which NETCONF capability URI indicates that the server supports rolling back configuration changes to previous commit points?
Juniper advertises specific capability URIs for commit features and rollbacks during the hello phase.
Why this answer
Junos supports rollback capabilities advertised via specific NETCONF capability URIs.
In a Python script utilizing PyEZ, what method must be called on the Device instance after all configuration and operational tasks are complete to properly terminate the NETCONF session?
Correct. dev.close() cleanly shuts down the NETCONF session.
Why this answer
The .close() method terminates the NETCONF session cleanly.
What is the primary benefit of using PyEZ Table and View abstractions over raw RPC XML parsing in Python scripts?
Correct. Tables and Views abstract XML parsing into clean Python objects.
Why this answer
Tables and Views abstract complex XML trees into clean Python dictionaries and lists.
Which service daemon must be explicitly enabled in the Junos CLI configuration to allow REST API requests to be processed by the routing engine?
Enabling jpagent starts the Junos REST API daemon.
Why this answer
The Junos REST API is managed by the 'jpagent' (Junos Plugin Agent) service. It must be enabled under the 'system services' hierarchy for REST API requests to function.
When using NETCONF to edit a Junos configuration, you include the attribute operation="create" on an existing configuration leaf. What behavior does the device exhibit?
'create' fails if the item already exists.
Why this answer
The 'create' operation adds a configuration node only if it does not already exist; if it exists, it returns an error.
An automation engineer is designing a Junos XML API workflow that uses the <get-config> operation. Which THREE parameters or filtering methods are valid when retrieving configuration data from a Junos device using NETCONF? (Choose three.)
The <source> element is mandatory in <get-config> to specify which datastore to retrieve.
Why this answer
Valid filtering and parameter methods for <get-config> include specifying the target datastore source, applying subtree filtering, and using xpath-based filters under specific namespace conditions.
Which character is used to indicate a mapping key-value pair in YAML syntax?
Correct. A colon separates keys and values in YAML mapping pairs.
Why this answer
In YAML, a key-value mapping is represented by a colon followed by a space (: ).
An automation pipeline tests Junos configuration changes against a virtual Junos device (such as vSRX or cRPD) in a CI environment before deploying to physical hardware. What is this practice called?
Correct. Using virtual network functions in CI pipelines validates changes safely before production.
Why this answer
Testing against virtualized network functions in a staging or CI environment is known as lab validation or digital twinning/staging.
Which TWO Python standard library modules are commonly combined when a script needs to fetch web content (such as Junos REST API data) and parse the resulting payload? (Choose two)
Correct. json is required to parse API responses.
An automation script executes a NETCONF <get-config> query with a specific subtree filter for interface statistics. However, the response contains configuration data instead of operational statistics. Why did this occur?
<get-config> only returns configuration; operational stats require <get>.
Why this answer
<get-config> retrieves configuration data, whereas operational statistics require the <get> RPC with operational filters.
You need to execute a custom remote procedure call (RPC) in PyEZ to retrieve the Ethernet switching table. The tag in Junos XML API is get-ethernet-switching-table-information. How should you write this method call in Python?
Correct. PyEZ converts hyphens in RPC names to underscores for Python method calls.
Why this answer
PyEZ maps XML RPC hyphens to Python underscores, allowing you to call rpc methods directly as attributes on dev.rpc.
You are configuring NETCONF traceoptions on a Junos device to debug an XML parsing issue. Which configuration statement enables logging of all NETCONF protocol messages to a file named 'netconf-debug.log'?
This is the correct Junos CLI syntax for enabling comprehensive NETCONF tracing.
Why this answer
Traceoptions under the netconf system services hierarchy control logging of NETCONF traffic.
Which tool or library is commonly used in Python to simplify interacting with Junos NETCONF APIs by abstracting low-level XML handling?
PyEZ provides high-level abstractions for Junos NETCONF APIs.
Why this answer
PyEZ is Juniper's official Python library designed specifically for interacting with Junos devices via NETCONF.
Which TWO components are essential parts of a model-driven network automation architecture on Junos devices? (Choose two)
Correct. YANG models define structured data schemas.
Why this answer
Model-driven architecture relies on structured data models (YANG) and standardized transport protocols (NETCONF, gRPC).
Which NETCONF RPC tag is used to gracefully terminate an active NETCONF session with a Junos device?
<close-session> gracefully closes the current NETCONF session.
Why this answer
The <close-session> RPC requests graceful termination of the NETCONF session.
Which TWO benefits are gained by applying DevOps principles to Junos network management? (Choose two)
Correct. Version control and automation ensure repeatability.
Why this answer
DevOps brings increased agility, faster deployments, better visibility, and reduced human error through automation and version control.
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?
Correct. Trunk-based development facilitates continuous integration and automated testing.
Why this answer
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.
Which TWO benefits are gained by using Python virtual environments when developing PyEZ and Jinja2 automation scripts? (Choose two)
Correct. Local package management gives version control.
Why this answer
Virtual environments isolate project dependencies and prevent version conflicts.
When executing a configuration commit in Junos via NETCONF, which TWO commit parameters or modifiers can be specified in the RPC? (Choose two)
Correct. Check-only validates the config without committing it to production.
Why this answer
NETCONF commit options on Junos include confirmed commits, check-only validation, log messages, etc.
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)
YAML is extensively used for playbooks, variable definitions, and configuration templates in tools like Ansible and PyEZ.
Why this answer
JSON and YAML are the primary lightweight data serialization formats universally utilized across modern network automation toolchains and APIs.
Which XML tag encapsulates the entire response returned by a Junos device in reply to a valid NETCONF RPC request?
RFC 6241 specifies <rpc-reply> as the container for responses to <rpc> requests.
Why this answer
Every NETCONF response from a Junos device is wrapped in an <rpc-reply> tag.
Which TWO configuration datastores are commonly supported and utilized when interacting with Junos devices via NETCONF? (Choose two)
The candidate datastore is where edits are staged before committing.
Why this answer
Junos primarily supports the candidate and running datastores for configuration management via NETCONF.
Correct. JSON keys are strictly strings, so json.loads() converts them to string keys in Python.
Why this answer
JSON specification dictates that object keys must be strings. When json.loads() parses an object, any keys (even if numeric-looking) are converted to Python strings.
When developing Python scripts that utilize PyEZ and Jinja2, which THREE best practices ensure robust and maintainable automation code? (Choose three)
Correct. Context managers handle resource cleanup safely.
Why this answer
Best practices include proper exception handling, using context managers, and separating templates from logic.
When executing an RPC call in PyEZ, what format is typically returned by default if you do not parse it into another structure?
Correct. PyEZ returns response data as an lxml Element object.
Why this answer
PyEZ RPC calls return an ElementTree object (XML Element) representing the response from the Junos device.
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?
PyEZ allows executing RPCs either dynamically via dev.rpc.get_interface_information() or via dev.rpc('get-interface-information').
Why this answer
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.
Which Junos automation tool utilizes NETCONF over SSH by default to manage network devices using Python libraries or configuration management frameworks?
Correct. Junos PyEZ is a Python library designed for Junos that uses NETCONF over SSH by default.
Why this answer
Ansible, PyEZ, and NETCONF clients communicate with Junos using NETCONF over SSH by default.
Which of the following data types is natively supported in JSON without requiring custom serialization handlers?
Correct. Boolean values (true and false) are natively supported primitive types in JSON.
Why this answer
JSON natively supports strings, numbers, booleans, null, arrays, and objects (dictionaries with string keys). Python tuples or sets are not natively supported.
A network automation engineer is utilizing the Junos PyEZ library in Python to manage device configurations. Which THREE methods or classes are part of the core Junos PyEZ library functionality? (Choose THREE)
ConnectError is a standard PyEZ exception raised when a connection cannot be established.
Why this answer
Junos PyEZ provides the Device class for connection management, the Config table/view context manager for configuration transactions, and exception handling classes like ConnectError.
When comparing the workflow and capabilities of the Junos REST API versus NETCONF, which THREE statements are correct? (Choose three)
NETCONF requires manual lock management, while REST API handles resource locking internally.
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?
mgd processes CLI, NETCONF, and Junos XML/JSON-RPC API requests.
Why this answer
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.
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?
Per-element attributes override the default-operation setting.
Why this answer
Per-element operation attributes override the default-operation specified at the transaction level.
A Python script receives a JSON payload from a Junos device containing 64-bit interface counter integers. When loaded using the standard 'json' module, the script experiences precision loss on counter values exceeding standard integer limits. Which alternative JSON parser package for Python should be used to handle high-precision integers without data degradation?
Correct. simplejson supports parsing numbers into Python Decimal objects to prevent precision loss.
Why this answer
The 'ujson' (UltraJSON) or 'simplejson' libraries provide options like parse_float or parse_int to handle high-precision numbers. Specifically, simplejson supports a 'use_decimal=True' parameter to decode JSON numbers into Python Decimal objects.
Port 3443 is the default TCP port for secure Junos REST API connections.
This follows the hierarchical Junos configuration REST path structure.
Why this answer
The Junos REST API uses structured paths matching the configuration hierarchy, typically prefixed by /api/configuraton/interfaces/interface/ge-0/0/0 or similar resource roots depending on the Junos release.
What is the primary benefit of using structured data formats (such as XML, JSON, or YAML) over unstructured CLI text output in Junos automation?
Correct. Structured data eliminates the need for complex, error-prone regex parsing of CLI text.
Why this answer
Structured data formats can be easily parsed programmatically without relying on fragile regular expressions.
Which Junos configuration hierarchy is used to configure system services parameters related to the REST API agent?
The jpagent hierarchy manages REST API configuration settings.
Why this answer
The jpagent service is configured under the 'set system services jpagent' CLI hierarchy.
Which THREE statements correctly contrast the session handling of NETCONF versus the Junos REST API? (Choose three)
NETCONF establishes a stateful SSH session with hello message capability exchanges.
You are configuring a webhook in your version control system to trigger an automated CI/CD pipeline whenever a developer pushes a configuration commit to the main branch of your Junos automation repository. What security mechanism should be implemented on the receiving pipeline webhook endpoint?
Correct. Secret tokens and signatures ensure webhook authenticity.
Why this answer
Webhooks should be secured using secret tokens or HMAC signatures to ensure requests genuinely originate from the trusted VCS platform.
Which TWO of the following are valid extensions commonly used for YAML files? (Choose two)
Correct. .yaml is a standard extension for YAML.
Why this answer
YAML files commonly use either .yaml or .yml file extensions.
When designing a custom PyEZ Table and View mapping in Python, what configuration parameter in the YAML definition file specifies the RPC or CLI command executed to gather the raw data?
Correct. The rpc key in a Table YAML definition specifies the XML RPC tag name.
Why this answer
The 'rpc' or 'command' keyword in a PyEZ Table YAML definition specifies the underlying command to run.
Port 3000 is the default TCP port for unencrypted Junos REST API connections.
In a DevOps pipeline managing Junos devices, an engineer implements 'Infrastructure as Code' (IaC). Which practice best exemplifies this methodology when applied to Junos routing policies?
Correct. Using templates, data files, version control, and automation tools embodies IaC.
Why this answer
IaC defines infrastructure in declarative configuration files stored in version control, allowing automated testing and deployment.
When writing a Python script to interact with Junos devices, you want to ensure that password credentials are not hardcoded in the source code. What is a recommended best practice supported by PyEZ?
Correct. PyEZ supports SSH keys and standard credential management practices.
Why this answer
PyEZ natively supports configuration files like ~/.junodes or passing parameters dynamically, but also respects environment variables or SSH keys.
You send an edit-config RPC with an invalid XML tag name. What is the standard structure of the error returned in the <rpc-reply>?
NETCONF protocol defines structured <rpc-error> XML blocks for reporting faults.
Why this answer
NETCONF errors are returned inside an <rpc-error> element containing details such as error-type, error-tag, and error-message.
Which TWO statements are true regarding the NETCONF protocol hello message exchange? (Choose two.)
Capabilities are advertised inside the <capabilities> element using specific capability URIs.
Why this answer
During the initial NETCONF hello message exchange, both the client and server advertise their supported capabilities using URIs, and the session ID is assigned by the server.
When establishing a NETCONF session over SSH, which standard capability announcement is exchanged during the initial hello message phase?
The base NETCONF capability URI is exchanged in the initial hello messages.
Why this answer
NETCONF capabilities are exchanged in <hello> messages at session startup, referencing URIs like urn:ietf:params:netconf:base:1.0.
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