Task dependencies (>> and << operators) in Apache Airflow - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the >> operator do in Airflow task dependencies?

The >> operator sets a downstream dependency, meaning the task on the left must run before the task on the right.

beginner

How does the << operator work in Airflow task dependencies?

The << operator sets an upstream dependency, meaning the task on the right must run before the task on the left.

beginner

How would you express that task A runs before tasks B and C using >> operator?

You write: A >> [B, C]. This means task A runs first, then tasks B and C run after.

beginner

Can you chain multiple tasks using >> operator? Example?

Yes. For example, A >> B >> C means A runs first, then B, then C in order.

intermediate

What happens if you mix >> and << operators in the same dependency chain?

They represent the same dependencies but from different directions. For example, A >> B is the same as B << A.

In Airflow, what does the expression 'task1 >> task2' mean?

A task1 runs before task2

B task2 runs before task1

C task1 and task2 run at the same time

D task1 depends on task2 to finish

The >> operator means the left task runs before the right task.

Which operator sets an upstream dependency in Airflow?

A ==

B >>

C <<

D !=

The << operator sets an upstream dependency, meaning the right task runs before the left.

How do you specify that task A runs before tasks B and C?

A A << [B, C]

B [B, C] >> A

C [B, C] << A

D A >> [B, C]

Using A >> [B, C] means A runs first, then B and C run after.

What does 'A >> B >> C' mean in Airflow?

A C runs, then B runs, then A runs

B A runs, then B runs, then C runs

C A, B, and C run simultaneously

D B depends on A and C

The chain means tasks run in sequence: A, then B, then C.

Is 'A >> B' equivalent to 'B << A' in Airflow?

A Yes, both mean A runs before B

B No, they mean opposite things

C Only if tasks are in the same DAG

D Only if tasks are different types

Both expressions set the same dependency: A runs before B.

Explain how to use the >> and << operators to set task dependencies in Airflow.

Think about which task runs first and which runs after.

Describe how to express multiple downstream tasks from a single upstream task using Airflow operators.

Use square brackets to group tasks.