200-901 Infrastructure and Automation — Timed 10 Questions

Question 1

Refer to the exhibit. Based on the output, which interface is experiencing a Layer 2 issue?

Accepted Answer

Serial0/0/0. The output shows that Serial0/0/0 is in the 'up/down' state (Status is up, Protocol is down), which indicates a Layer 2 issue. Common causes include an encapsulation mismatch, missing keepalive, or a problem with the data link layer. This is distinct from a Layer 1 issue, which would show 'down/down' (Status and Protocol both down).

Answer

Loopback0

Answer

GigabitEthernet1

Answer

GigabitEthernet2

Question 2

An engineer needs to automate the deployment of a new VLAN across multiple switches. Which tool is best suited for this task?

Accepted Answer

Ansible. Ansible is the correct tool because it is an agentless automation platform that uses SSH to push configuration changes, such as VLAN deployment, to network devices. It allows engineers to define the desired state of VLANs in YAML playbooks and apply them consistently across multiple switches without manual intervention.

Answer

NetFlow

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Syslog

Answer

SNMP

Question 3

A DevOps team wants to version control their network configurations. Which tool should they use?

Accepted Answer

Git. Git is a distributed version control system that tracks changes in source code and configuration files, making it the ideal tool for version controlling network configurations. Unlike configuration management tools, Git provides commit history, branching, and rollback capabilities specifically designed for version control.

Answer

Puppet

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Jenkins

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Docker

Question 4

During an automation script run, a network device returns HTTP 429. What does this indicate?

Accepted Answer

Rate limiting. HTTP 429 (Too Many Requests) indicates the client has sent too many requests in a given amount of time, triggering rate limiting on the server. In network automation, devices like routers or switches enforce rate limits to prevent resource exhaustion, often based on RFC 6585. This is common when automation scripts exceed API call thresholds, requiring retry logic with exponential backoff.

Answer

Internal server error

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Authentication failure

Answer

Resource not found

Question 5

A network automation engineer is writing a Python script to configure multiple devices. Which library is most appropriate for SSH-based interactions?

Accepted Answer

Netmiko. Netmiko is a Python library built on top of Paramiko that simplifies SSH connections to network devices. It provides high-level methods for sending commands, handling prompts, and managing device interactions, making it the most appropriate choice for automating configuration tasks across multiple devices.

Answer

requests

Answer

socket

Answer

paramiko

Question 6

In a CI/CD pipeline for network changes, which practice best ensures that a configuration push does not disrupt production traffic?

Accepted Answer

Canary deployment. Canary deployment is the correct practice because it gradually introduces the configuration change to a small subset of devices or traffic before full rollout. This allows monitoring for adverse effects and automatic rollback if issues arise, minimizing the risk of production disruption. In a CI/CD pipeline for network changes, this approach aligns with incremental validation and risk mitigation.

Answer

Disable rollback

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Push all changes at once

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Skip validation

Question 7

An engineer uses Ansible to push a configuration change to 100 switches. The playbook fails on 5 switches. What is the most efficient way to apply the change only to those 5?

Accepted Answer

Use Ansible's --limit with the retry file. Ansible generates a retry file by default when a playbook fails on some hosts. Using `--limit @<retry-file>` re-runs the playbook only against the failed hosts, avoiding unnecessary execution on the 95 successful switches. This is the most efficient method because it targets only the problematic devices without manual intervention or full re-runs.

Answer

Use --skip-tags on successful hosts

Answer

Re-run the playbook on all switches

Answer

Manually configure the 5 switches

Question 8

Which protocol is commonly used to retrieve real-time telemetry data from network devices in a streaming fashion?

Accepted Answer

gRPC. gRPC is correct because it is designed for high-performance, real-time streaming of telemetry data using HTTP/2 and Protocol Buffers. Network devices like Cisco IOS XR and NX-OS use gRPC to push telemetry data to collectors in a continuous stream, eliminating the need for polling and reducing latency.

Answer

SNMP polling

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NETCONF

Answer

HTTP

Question 9

A company uses a centralized automation server that runs Ansible playbooks. What is the best security practice for storing SSH credentials?

Accepted Answer

Use Ansible Vault. Ansible Vault is the recommended security practice for encrypting sensitive data like SSH credentials. It allows you to store encrypted variables and files within your playbooks or inventory, protecting secrets at rest while enabling decryption at runtime via a password or key file. This avoids exposing credentials in plain text, which is critical for centralized automation servers that may be accessed by multiple users or integrated into CI/CD pipelines.

Answer

Store credentials in a public repository

Answer

Hardcode credentials in playbooks

Answer

Use plain text inventory files

Question 10

In a network automation workflow, a developer needs to ensure idempotency. What does idempotency mean in this context?

Accepted Answer

Running the script once produces the same result as running it multiple times. Idempotency in network automation means that executing an operation multiple times results in the same network state as executing it once. For example, using a REST API PUT request to set a VLAN configuration will leave the device in the same state whether the request is sent once or repeatedly, because PUT is inherently idempotent. This prevents unintended side effects like duplicate VLANs or interface misconfigurations when a script is retried due to network failures or timeouts.

Answer

The script uses a single API call

Answer

The script can recover from failures

Answer

The script can run on multiple devices simultaneously