What is Apache Airflow - Practice Questions & Exercises

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Apache Airflow's Purpose

What is the primary purpose of Apache Airflow in a DevOps environment?

A To automate and schedule complex workflows and data pipelines

B To serve as a web server for hosting websites

C To monitor network traffic and detect intrusions

D To manage container orchestration like Kubernetes

💡 Hint

Think about what Airflow helps automate and organize.

Apache Airflow is designed to automate, schedule, and monitor workflows, especially data pipelines, making complex tasks easier to manage.

💻 Command Output

intermediate

Airflow Webserver Startup Output

What output will you see when you successfully start the Apache Airflow webserver using the command airflow webserver?

Apache Airflow

airflow webserver

A Error: command not found

B

Starting the web server on port 8080
Listening on http://localhost:8080

C Database connection failed

D Kubernetes cluster not found

💡 Hint

Look for a message indicating the webserver is running and the port number.

When the Airflow webserver starts successfully, it listens on port 8080 by default and shows a message with the URL.

❓ Configuration

advanced

Configuring Airflow Executor

Which configuration setting in airflow.cfg correctly sets the executor to use CeleryExecutor?

Apache Airflow

[core]
executor = SequentialExecutor

A

[core]
executor = CeleryExecutor

B

[core]
executor = KubernetesExecutor

C

[core]
executor = SequentialExecutor

D

[core]
executor = LocalExecutor

💡 Hint

The executor setting defines how tasks are run in Airflow.

Setting executor = CeleryExecutor enables distributed task execution using Celery workers.

🔀 Workflow

advanced

Airflow DAG Scheduling Behavior

Given a DAG scheduled with schedule_interval='@daily' and a start date of 2024-06-01, when will the first DAG run be triggered?

A At midnight on 2024-06-01

B Immediately when the DAG is deployed

C At midnight on 2024-06-02

D At noon on 2024-06-01

💡 Hint

Airflow schedules runs after the period ends.

Airflow triggers the first run at the end of the first schedule interval, so the run for 2024-06-01 is triggered at midnight on 2024-06-02.

❓ Troubleshoot

expert

Diagnosing Airflow Task Failure

You notice a task in your Airflow DAG is stuck in the 'queued' state indefinitely. Which is the most likely cause?

A The Airflow webserver is down

B The DAG file has syntax errors

C The task has already succeeded

D No available worker to pick up the task

💡 Hint

Think about what controls task execution after queuing.

If no worker is available, tasks remain queued and do not start running.