200-901 Practice Test 49 — 15 Questions

Question 1

Given the Python list comprehension: result = [x*2 for x in range(10) if x > 5]
What is the value of result?

Accepted Answer

[12, 14, 16, 18]. The list comprehension `[x*2 for x in range(10) if x > 5]` iterates over `x` from 0 to 9, filters to only include `x` values greater than 5 (i.e., 6, 7, 8, 9), and multiplies each by 2, producing `[12, 14, 16, 18]`. This is a standard Python comprehension with a conditional filter.

Answer

[0, 2, 4, 6, 8, 10, 12, 14, 16, 18]

Answer

[10, 12, 14, 16, 18]

Answer

[6, 7, 8, 9]

Question 2

A Python function is designed to fetch device data from multiple sources. It uses *args to accept variable number of API endpoints and **kwargs for optional parameters like timeout. Which function definition correctly implements this?

Accepted Answer

def fetch_devices(*endpoints, **options):. It uses *endpoints to accept a variable number of positional arguments (the API endpoint strings) and **options to accept any number of keyword arguments (like timeout=30). This matches the requirement for a function that can handle multiple sources with optional parameters, following Python's standard *args/**kwargs pattern.

Answer

def fetch_devices(**endpoints, *options):

Answer

def fetch_devices(endpoints, **options):

Answer

def fetch_devices(*endpoints, options):

Question 3

What is the purpose of the 'Authorization' header in a REST API request?

Accepted Answer

To authenticate the client. The Authorization header carries credentials (e.g., Bearer token, Basic auth) to authenticate the client. Content-Type specifies body format. Accept specifies response format.

Answer

To enable caching of the response

Answer

To specify the desired response format

Answer

To specify the format of the request body

Question 4

A developer is designing a microservices-based network management system. One requirement is that when a new device is discovered, multiple other services must be notified asynchronously to perform tasks like inventory update, monitoring setup, and log collection. Which architectural pattern best fits this requirement?

Accepted Answer

Event-driven architecture. The event-driven architecture is correct because it enables asynchronous, decoupled communication between services. When a new device is discovered, an event (e.g., a message on a message broker like Kafka or RabbitMQ) is published, and multiple subscriber services (inventory, monitoring, logging) react independently without blocking the discovery service. This pattern directly supports the requirement for loose coupling and asynchronous notification.

Answer

Model-View-Controller (MVC)

Answer

RESTful API

Answer

Monolithic architecture

Question 5

A team uses a Jenkins declarative pipeline to deploy a microservice. The pipeline includes stages: Checkout, Build Docker Image, Run Unit Tests, Push to Registry, Deploy to Staging, and Deploy to Production. Which stage should run immediately after 'Build Docker Image' to ensure code quality before the image is pushed?

Accepted Answer

Run Unit Tests. After building the Docker image, the next logical step is to run unit tests to verify code quality before pushing the image to a registry.

Answer

Deploy to Staging

Answer

Deploy to Production

Answer

Push to Registry

Question 6

During a network outage, a technician notices that hosts in VLAN 10 cannot reach the default gateway at 192.168.10.1, but hosts in VLAN 20 can. The switch interfaces are up, and the router is configured with subinterfaces. What is the most likely cause?

Accepted Answer

The router subinterface for VLAN 10 is down or misconfigured.. The router subinterface for VLAN 10 is down or misconfigured. Since hosts in VLAN 10 cannot reach the default gateway but hosts in VLAN 20 can, the issue is isolated to VLAN 10. The router uses subinterfaces to route between VLANs via a trunk link; if the subinterface for VLAN 10 is down (e.g., no 'no shutdown' command) or misconfigured (e.g., wrong VLAN ID or encapsulation), it will not process traffic for that VLAN, while other subinterfaces remain functional.

Answer

The trunk link is administratively down.

Answer

The switchport trunk native VLAN is mismatched.

Answer

The router does not have an IP address configured.

Question 7

A developer is using the Cisco Webex Teams API to create a room and add members. The API returns a 400 error. What is the most likely cause?

Accepted Answer

Missing required fields. A 400 Bad Request error from the Cisco Webex Teams API indicates that the server cannot process the request due to a client-side error, most commonly missing required fields in the request body. When creating a room, the API requires a 'title' field; omitting it or sending an empty value triggers a 400 response. This is distinct from authentication or network issues, which produce different HTTP status codes.

Answer

Invalid access token

Answer

Network connectivity issue

Answer

Room name already exists

Question 8

A DevOps team is using Cisco AppDynamics to monitor a microservices application. They notice that a specific service's response time spikes under load. Which AppDynamics feature should be used to drill down into the transaction trace?

Accepted Answer

Transaction Snapshots. Transaction Snapshots in AppDynamics capture detailed traces of individual requests, including call chains, method timings, and database queries. When a response time spike occurs, drilling into Transaction Snapshots provides the precise data needed for root-cause analysis. Business Transactions are logical groupings of similar transactions; while they can be used to locate the problematic transaction, the direct drill-down feature for detailed traces is the Transaction Snapshot.

Answer

Health Rules

Answer

Business Transactions

Answer

Service Endpoints

Question 9

Which Docker command is used to build an image from a Dockerfile?

Accepted Answer

docker build. The `docker build` command reads the instructions in a Dockerfile and assembles a Docker image layer by layer. Each instruction in the Dockerfile (e.g., FROM, RUN, COPY) creates a new layer that is cached and reused, making subsequent builds faster. This is the standard and only command designed specifically for building images from a Dockerfile.

Answer

docker run

Answer

docker commit

Answer

docker create

Question 10

A developer wants to deploy a containerized application on a Cisco Container Platform (CCP) cluster. The application requires persistent storage. Which Kubernetes resource should be used to provision storage?

Accepted Answer

PersistentVolumeClaim. PersistentVolumeClaim (PVC) is the correct Kubernetes resource for requesting persistent storage. A PVC binds to a PersistentVolume (PV) that provides storage independent of pod lifecycle. ConfigMap is for configuration data, not persistent storage. Secrets store sensitive data, Services enable network access, and neither provides persistent storage.

Answer

Secret

Answer

Service

Answer

ConfigMap

Question 11

A network engineer runs an Ansible playbook to backup a Cisco router configuration. The playbook fails with the error: 'ssh: connect to host 192.168.1.1 port 22: Connection timed out'. What is the most likely cause?

Accepted Answer

The router's IP address is unreachable from the control node.. The error 'Connection timed out' indicates that the control node sent a TCP SYN to 192.168.1.1 on port 22 but never received a SYN-ACK response. This occurs when the destination IP is unreachable due to routing issues, a firewall dropping packets, or the host being offline. Since Ansible uses SSH to connect to network devices, a timeout at the transport layer points directly to network reachability problems, not authentication or service configuration.

Answer

The playbook uses the incorrect gather_facts setting.

Answer

The SSH key is not authorized on the router.

Answer

The router does not have SSH enabled.

Question 12

A developer is building a RESTful API with Python Flask. Which TWO are recommended security best practices for exposing the API over HTTPS?

Accepted Answer

Validate and sanitize all user input.. Option B is correct because validating and sanitizing all user input defends against injection attacks (SQL injection, XSS, command injection) and malformed payloads that could compromise a Flask REST API, and it should be applied to query parameters, path variables, headers, and JSON bodies. Option E is correct because rate limiting (e.g., via Flask-Limiter with limits like 100 requests per minute per IP or API key) mitigates brute-force, credential-stuffing, and denial-of-service abuse against exposed HTTPS endpoints. Option A is not recommended: HTTP Basic Authentication sends base64-encoded credentials that are only protected by TLS and lacks token expiry, MFA, and scoping, so it is considered weak for API security. Option C is wrong because enabling CORS for all origins (Access-Control-Allow-Origin: *) exposes the API to cross-origin data theft and should be restricted to trusted origins. Option D is wrong because storing passwords in plaintext violates fundamental credential-storage practice; passwords must be hashed with a slow algorithm such as bcrypt, scrypt, or Argon2.

Answer

Use HTTP Basic Authentication for simplicity.

Answer

Enable CORS for all origins.

Answer

Store passwords in plaintext in the database.

Question 13

Which HTTP method is considered both safe and idempotent?

Accepted Answer

GET. GET is both safe and idempotent according to HTTP semantics (RFC 7231). Safe means it must not cause side effects on the server, and idempotent means multiple identical requests produce the same result as a single request. GET is designed solely for retrieval of a resource, so it satisfies both properties.

Answer

POST

Answer

PUT

Answer

PATCH

Answer

DELETE

Question 14

In Python, which data type is used to represent an unordered collection of unique elements?

Accepted Answer

set. In Python, a set is the correct data type for representing an unordered collection of unique elements. Sets automatically enforce uniqueness by using a hash table internally, so duplicate values are ignored upon insertion. This makes them ideal for operations like membership testing and deduplication, where order is irrelevant.

Answer

tuple

Answer

list

Answer

dict

Question 15

Which command enables the NX-API feature on a Cisco NX-OS device?

Accepted Answer

feature nxapi. The global configuration command 'feature nxapi' enables the NX-API interface.

Answer

restconf enable

Answer

nxapi enable

Answer

enable nxapi