Troubleshooting Airflow web server issues

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This page provides troubleshooting steps and information for common Airflow web server issues.

The Airflow web server is an Airflow component that provides a user interface for managing Airflow DAGs and tasks. This page describes troubleshooting steps for various issues with accessing the Airflow web server of your environment or for web server-related warnings visible in Airflow logs.

Can't access Airflow UI when network access controls are enabled

Symptom: After web server access controls are configured, it's not possible to access Airflow UI. Usually, the error code displayed in this situation is 403.

Information about the issue: Cloud Composer supports web server network access controls, which lets you specify IP ranges that are allowed to connect to the web server.

Problems with accessing Airflow UI usually result in error 403. To check if the error is related to web server network access controls, do the following:

  1. In the list of environments, click the name of your environment. The Environment details page opens.
  2. Go to the Environment configuration tab.
  3. Check if the Web server access control item is set to All IP addresses have access (default).
  4. If a value different than All IP addresses have access (default) is configured, then network access control is enabled and the visibility of the Airflow UI is limited to the provided IPv4 and IPv6 address ranges. In this case, the problem might be related to web server network access controls.

In most cases, the cause of the issue is the mismatch between the intended IP that you specified and the IP that is actually resolved to connect to the Airflow UI. To troubleshoot the problem, do the following:

  1. In the list of environments, click the name of your environment. The Environment details page opens.

  2. Go to the Environment configuration tab.

  3. Find the Web server access control item and click Edit.

  4. In the Web server network access control dialog, select Allow access from all IP addresses.

  5. Access the Airflow UI multiple times and verify that it works without any issues:

    • If you don't experience problems, continue to the next step.

    • If you experience a problem at this point, it means that the issue might be related to your IAM permissions configuration. For more information about the IAM permissions for Cloud Composer, see Access control.

  6. In the Web server network access control dialog, select Allow access only from specific IP addresses.

  7. Add the 0.0.0.0/0 IP range, then access the Airflow UI multiple times and verify that it works without issues:

    • If you don't experience problems, then the IP that you're connecting with is an IPv4 address.

    • If you experience a problem at this point, it means the IP you're connecting with is an IPv6 address.

  8. Delete the 0.0.0.0/0 IP range, and add the ::/0 IP range.

    • If you don't experience problems, then the IP that you're connecting with is an IPv6 address.

    • If you experience a problem at this point, it means the IP you're connecting with is an IPv4 address.

  9. Now you determined if your resolved address is IPv4 or IPv6.

  10. Depending on the address type, narrow down the ::/0 or 0.0.0.0/0 ranges to more specific ones, to verify the broadest range when the access stops working:

    • You can start with the wide subnet mask (such as 192.0.2.0/8) that includes the address that you assume to be your IP address.

    • To determine your IP address, you can use a third-party service that provides your external IP address when you visit its page. You can search for such services by the "what is my IP address" search query).

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