AirflowHow-ToBeginner · 3 min read

How to Start Airflow Webserver: Simple Steps to Launch UI

To start the Airflow webserver, run the command airflow webserver in your terminal. This launches the Airflow UI on the default port 8080, accessible via http://localhost:8080.

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Syntax

The basic command to start the Airflow webserver is:

airflow webserver: Starts the webserver process.
--port <port_number>: Optional flag to specify a custom port (default is 8080).
--daemon: Optional flag to run the webserver in the background.

bash

airflow webserver [--port 8080] [--daemon]

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Example

This example starts the Airflow webserver on the default port 8080 in the foreground. You can then open your browser and go to http://localhost:8080 to access the Airflow UI.

bash

airflow webserver

Output

Starting the Airflow webserver on port 8080 [2024-06-xx xx:xx:xx,xxx] {webserver.py:xxx} INFO - Starting gunicorn 20.x.x [2024-06-xx xx:xx:xx,xxx] {webserver.py:xxx} INFO - Listening at: http://0.0.0.0:8080 (xxxx) [2024-06-xx xx:xx:xx,xxx] {webserver.py:xxx} INFO - Using worker: sync [2024-06-xx xx:xx:xx,xxx] {webserver.py:xxx} INFO - Booting worker with pid: xxxx

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Common Pitfalls

Common mistakes when starting the Airflow webserver include:

Not initializing the Airflow database with airflow db init before starting the webserver.
Trying to start the webserver without activating the correct Python environment where Airflow is installed.
Port 8080 already in use by another application, causing the webserver to fail to start.
Running the webserver without starting the scheduler, which is needed to run workflows.

bash

Wrong: airflow webserver
# Fails if DB not initialized or port busy

Right:
airflow db init
airflow webserver --port 8080

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Quick Reference

Summary tips for starting Airflow webserver:

Always run airflow db init once before starting the webserver.
Use --port to change the default port if needed.
Use --daemon to run the webserver in the background.
Access the UI at http://localhost:8080 by default.

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Key Takeaways

Run airflow webserver to start the Airflow UI on port 8080 by default.

Initialize the Airflow database first with airflow db init to avoid errors.

Use --port to specify a different port if 8080 is busy.

Run the webserver in the background with --daemon if needed.

Access the Airflow UI at http://localhost:8080 after starting the webserver.