200-901 Exam Dumps - Cisco Certified DevNet Associate Questions and Answers

Load balancers distribute network or application traffic across multiple servers to ensure no single server becomes overwhelmed. In modern application deployment, load balancers allow traffic to continue smoothly as new compute units are brought online and old units are decommissioned. This ensures high availability and reliability of services.

The task is to determine which command correctly outputs the page_id value from the JSON payload shown in the Python 3.7 script. Let’s analyze the options and the payload structure to verify the correct answer.

JSON Payload Analysis:

The JSON payload provided in the exhibit shows that items is a key in the top-level dictionary.

The value of items is a list of dictionaries, and each dictionary contains various keys, including page_id.

Code Analysis:

The JSON data returned by the get_json function is assigned to the variable items.

The goal is to access the page_id key within the first dictionary of the list associated with the items key.

Options Analysis:

Option A: print(items['items']['page_id'])

This will not work because items['items'] is a list, not a dictionary. Attempting to access ['page_id'] directly from a list will result in a TypeError.

Option B: print(items.get('items').get('page_id'))

This will also not work for the same reason as Option A. items.get('items') returns a list, and calling .get('page_id') on a list is invalid.

Option C: print(items.get('items')[0].get('page_id'))

This is correct. items.get('items') returns the list, [0] accesses the first element of the list (which is a dictionary), and .get('page_id') retrieves the value of the page_id key from that dictionary.

Option D: print(items['items']['page_id'].keys())

This will fail because items['items'] is a list and does not have a keys() method.

Correct Explanation:

The JSON structure contains a list under the key items.

To access page_id, we first need to get the first dictionary in this list ([0]).

We then access the page_id key in this dictionary.

Example:

print(items.get('items')[0].get('page_id'))

This code correctly navigates through the structure and retrieves the value associated with page_id.

References:

Python Documentation on Dictionaries: Python Docs

JSON Data Handling in Python: Python JSON

The exhibit illustrates a Continuous Integration/Continuous Deployment (CI/CD) pipeline. This method involves continuous integration of code from multiple developers, automated testing, and continuous delivery/deployment to production. It ensures that code changes are automatically built, tested, and deployed, promoting efficient and reliable software development practices.

The agile process allows for incremental delivery of features, meaning new functionalities can be added or existing ones updated in small, manageable increments. This is in contrast to the waterfall model, where all phases are completed before the product is delivered. Agile enables continuous improvement and adaptation to changing requirements throughout the development process.

The Waterfall method is a sequential software development process where a phase begins only after the previous phase has ended. In contrast, Agile development involves iterative processes where phases run in parallel and are continuously improved upon.

A. Waterfall increases agility to implement faster while Agile promotes reliability - Incorrect. This is the opposite of the typical characteristics of these methods. B. A phase begins after the previous phase has ended in Waterfall while Agile phases run in parallel - Correct. Waterfall is linear and sequential, while Agile is iterative and parallel. C. Customers get feedback during the process in Waterfall while they can see the result at the end in Agile - Incorrect. Agile involves continuous feedback, whereas Waterfall typically provides feedback only at the end. D. Requirements can be updated in Waterfall while in Agile it should be gathered in the beginning - Incorrect. Requirements in Agile can be updated continuously, while Waterfall requires requirements to be defined upfront.

References:

Waterfall vs. Agile Methodologies

A reverse proxy can be used to route external requests to different applications on the same host machine using a single public IP address and port. It forwards the requests to the appropriate backend servers based on the request URL or other routing rules.

Single Entry Point: A reverse proxy serves as a single entry point to multiple applications, making it ideal for managing traffic to multiple services hosted on the same machine.

Routing Requests: It can route requests to different internal ports based on the requested URL or other criteria.

Option A is the correct choice as a reverse proxy handles external access to multiple applications on the same host.

Agentless configuration management systems, such as Ansible, do not require agents to be installed on the managed hosts. Instead, they leverage existing protocols and services to perform configuration tasks.

Agentless Approach: These systems rely on protocols like SSH (for Unix/Linux) or WinRM (for Windows) to communicate with and manage the hosts.

No Agent Installation: Managed hosts do not need any additional software (agents) installed, which simplifies management and reduces overhead.

Interpreters: They may require the managed hosts to have an interpreter for scripts (e.g., Python) but primarily use existing network protocols for communication.

Option D correctly identifies that agentless configuration management systems use existing protocols to interface with managed hosts.

Synchronous API requests and asynchronous API requests differ primarily in how and when the client receives a response from the server.

Synchronous API Request: In a synchronous API call, the client sends a request to the server and waits for a response. The client is blocked during this time, meaning it cannot perform other tasks until the server responds. The key characteristic is that the client is able to access the results immediately after the request is processed. This is suitable for operations that need an immediate response and where the processing time is relatively short.

Asynchronous API Request: In an asynchronous API call, the client sends a request and continues its process without waiting for the server to respond. The server processes the request and sends the response back to the client at a later time. The client might receive a task ID (option A), subscribe to a webhook (option B), or poll for status (option D) to check when the operation is complete.

The primary security issue in this scenario is that API keys are stored in the configuration files. It is a best practice to store sensitive information such as API keys in a secure vault service rather than in configuration files.

A. Communication between the application and the services is not encrypted - Incorrect. The communication is through HTTPS, which is encrypted. B. The database credentials should be stored in the configuration files so that they are secured on the same server - Incorrect. Database credentials should be securely obtained, as mentioned, through a vault service. C. The API keys are stored in the configuration files but should be stored in the vault service - Correct. Storing API keys in configuration files poses a security risk. They should be stored in a secure vault service. D. The synchronization logs should be encrypted and not stored in a relational database - Incorrect. The issue is not about storing logs in a relational database, but rather the storage of API keys in configuration files.

References:

Secure Secrets Management

Best Practices for Storing API Keys

The sequence diagram shows the process where the API client first calls the /organizations endpoint to get the list of organization IDs. Then, for each organization, it makes a call to the /organizations/(orgId)/networks endpoint to retrieve the networks for that organization. Since there are two organizations, the GetAllNetworks function will make two parallel calls to the /organizations/(orgId)/networks endpoint, one for each organization.

References:

Cisco DevNet Associate Study Guide: Using Cisco Meraki APIs (Chapter 7, Section: Understanding Meraki API Calls and Endpoints).