JN0-224 sample questions

Question 1

When defining infrastructure variables for configuration management tools like Ansible, what is the primary advantage of using YAML over JSON?

Accepted Answer

Enhanced human readability and support for comments.

Answer

Faster parsing speed for large datasets.

Answer

Stricter data typing and schema enforcement.

Answer

Wider support across web-based APIs.

Question 2

A network automation team is integrating JSNAPy into their CI/CD pipeline to validate network changes. At which stage of the pipeline would the execution of JSNAPy tests provide the most value?

Accepted Answer

During the 'Test' and 'Deploy' stages, before and after applying changes to a device.

Answer

During the 'Build' stage, alongside code compilation.

Answer

During the 'Commit' stage, before code is merged to the main branch.

Answer

During the 'Monitor' stage, as a periodic health check.

Question 3

Which cURL command correctly uses the Junos REST API to replace the entire configuration for the `ge-0/0/1` interface with content from a local file named `interface.json`?

Accepted Answer

curl -X PUT -u user:pass -H 'Content-Type: application/json' https://device/configuration/interfaces/interface/ge-0_0_1 --data @interface.json

Answer

curl -X GET -u user:pass -H 'Content-Type: application/json' https://device/rpc/get-configuration --data @interface.json

Answer

curl -X POST -u user:pass -H 'Accept: application/json' https://device/rpc/load-configuration -d @interface.json

Answer

curl -X PATCH -u user:pass -H 'Content-Type: application/json' https://device/configuration/interfaces/interface/ge-0_0_1 -d @interface.json

Question 4

A Python script using PyEZ needs to retrieve the BGP summary information and then process only the neighbors that are in the 'Established' state. Given that `dev.rpc.get_bgp_summary_information()` returns a complex XML object, what is the most effective way to access the desired data?

Accepted Answer

Use the `.find()` and `.findall()` methods with an XPath expression to directly select `bgp-peer` elements where `peer-state` is 'Established'.

Answer

Convert the XML object to a string and use regular expressions to find neighbors with the 'Established' state.

Answer

Iterate through every element in the XML object recursively and check if its text value is 'Established'.

Answer

Use the `get_bgp_neighbor_information()` RPC instead, as it returns data in a simpler format.

Question 5

What is the function of the `operation="merge"` attribute within a NETCONF ` ` RPC sent to a Junos device?

Accepted Answer

It compares the provided configuration with the target datastore and only adds or modifies elements.

Answer

It replaces the entire existing configuration with the new configuration provided in the RPC.

Answer

It deletes any configuration elements that are present in the target datastore but not in the RPC.

Answer

It creates the configuration elements only if they do not already exist in the target datastore.

Question 6

**Company Background:**
Global Financial Services Inc. operates a large-scale network with strict compliance and uptime requirements. Network changes are only permitted during scheduled weekly maintenance windows and must be rigorously validated to prevent service disruptions. The network operations team is small and needs to automate as much of the change validation process as possible to reduce human error and meet tight deadlines.

**Current Situation:**
The team currently relies on manual CLI commands to check the state of core routers before and after applying configuration changes. This process is slow, error-prone, and generates inconsistent reports. They have decided to build an automated solution using Python, leveraging the PyEZ library for device interaction and JSNAPy for state validation.

**Technical Requirements:**
1. The solution must be a single Python script that can be executed from a central automation server.
2. Before applying any changes, the script must capture a 'pre-change' snapshot of the device state. This must include the full IPv4 routing table, the status of all BGP sessions, and the operational status of all physical interfaces.
3. After changes are applied (manually or by another script), the script must capture a 'post-change' snapshot of the same data points.
4. The script must compare the two snapshots and generate a simple, clear report indicating a PASS or FAIL status. A FAIL status should be triggered if any BGP sessions have dropped, any critical interfaces have gone down, or if specific critical routes are missing from the routing table.

**Constraint:**
The solution must not require any custom daemons or agents to be installed on the Junos devices themselves.

Which approach best satisfies all the requirements for this automated validation solution?

Accepted Answer

Create a JSNAPy configuration file that defines tests for `RouteTable`, `BGPSummary`, and `InterfaceTable`. Write a Python script that uses the `jsnapy` library to connect to the device, execute `jsnapy --snap pre`, wait for changes, execute `jsnapy --snap post`, and then run `jsnapy --check pre post` to generate the PASS/FAIL report.

Answer

Write a Python script that uses PyEZ to connect to the device, execute `show route`, `show bgp summary`, and `show interfaces terse` commands, parse the text output using regular expressions, and manually compare the pre- and post-change outputs.

Answer

Develop an Ansible playbook that uses the `juniper.junos.command` module to gather outputs and the `assert` module to validate conditions. The playbook will have separate plays for pre-check, change implementation, and post-check.

Answer

Configure on-box event scripts on each Junos device to monitor for configuration commits. The scripts will automatically capture the required operational state to a local file, which can then be retrieved and compared by a central Python script.

Question 7

An engineer is creating a YAML file to store a list of NTP servers. Which of the following snippets are syntactically correct representations of a list in YAML? (Select TWO)

Accepted Answer

ntp_servers:
- 192.0.2.1
- 192.0.2.2

Accepted Answer

ntp_servers: [192.0.2.1, 192.0.2.2]

Answer

ntp_servers: (192.0.2.1, 192.0.2.2)

Answer

ntp_servers:
192.0.2.1
192.0.2.2

Answer

ntp_servers: {192.0.2.1, 192.0.2.2}

Question 8

True or False: In a mature DevOps workflow, the principle of Infrastructure as Code (IaC) encourages defining network configurations in version-controlled files, which are then used to automate deployments, ensuring consistency and repeatability.

Accepted Answer

True

Answer

False

Question 9

A PyEZ script attempts to apply a complex configuration change but fails during the commit phase, raising a `CommitError` exception. The operational requirement is that any failed commit must leave the device in its original state. How should the script's error handling be structured to meet this requirement and provide detailed logs for troubleshooting?

Accepted Answer

Wrap the `cu.commit()` call in a `try...except CommitError as e` block. In the `except` block, call `cu.rollback()` and then log the contents of the exception object `e`.

Answer

Wrap the `cu.commit()` call in a `try...except CommitError` block. In the `except` block, call `cu.load()` again with the original configuration.

Answer

Use `cu.commit(check=True)` first, and if it passes, then call `cu.commit()` inside a `try...except` block.

Answer

Before committing, save a copy of the running configuration using `dev.rpc.get_configuration()`. If `cu.commit()` fails, use `cu.load()` with the saved configuration and `overwrite=True`.

Question 10

An engineer needs to retrieve only the configuration for the `ge-0/0/0` interface and all its subunits from a Junos device using a single NETCONF ` ` operation. Which XML filter provides the most precise way to request this specific data?
```mermaid
flowchart TD
A[Client: Construct get-config RPC] --> B{Add XML Filter for ge-0/0/0};
B --> C[Send RPC to Junos Device];
C --> D[Device: Process Filter];
D --> E[Device: Return ONLY ge-0/0/0 Config];
E --> F[Client: Receive Filtered XML Data];
```

Accepted Answer

ge-0/0/0

Answer

Answer

Answer

Free JN0-224 sample questions