Introducing in-place version upgrades with Amazon MWAA

Today, AWS is announcing the availability of in-place version upgrades for Amazon Managed Workflow for Apache Airflow (Amazon MWAA). This enhancement allows you to seamlessly upgrade your existing Apache Airflow version 2.x environments to newer available versions while retaining the workflow run history and environment configurations. You can now take advantage of the latest capabilities of the Apache Airflow platform without having to create an entirely new Amazon MWAA environment.

Until now, if you wanted to upgrade your Amazon MWAA environment to a different Apache Airflow version, you had to follow the Amazon MWAA environment migration instructions. This involved creating a new Amazon MWAA environment and then migrating all of your configurations and Directed Acyclic Graphs (DAGs) to it. If you also needed to preserve the history of DAG runs, you had to take a backup of your metadata database and then restore that backup on the newly created environment. This process was error prone, manual, and involved additional costs to maintain two separate Amazon MWAA environments until you could verify the new and decommission the old.

In this post, we provide an overview of the in-place version upgrade feature, explore applicable use cases, detail the steps to use it, and provide additional guidance on its capabilities.

Overview of solution

The newly introduced in-place version upgrades by Amazon MWAA provide a streamlined transition from your existing Apache Airflow version 2.x-based environments to newer available Apache Airflow versions. Amazon MWAA manages the entire upgrade process, from provisioning new Apache Airflow versions to upgrading the metadata database. In the event of an upgrade failure, Amazon MWAA is designed to roll back to the previous stable version using the associated metadata database snapshot.

Upgrading your existing environments on Amazon MWAA is a straightforward process. You can upgrade your existing Apache Airflow 2.0 and later environments on Amazon MWAA with just a few clicks on the Amazon MWAA console, by using the Amazon MWAA API, the AWS Command Line Interface (AWS CLI), or by using tools like AWS CloudFormation, the AWS Cloud Development Kit (AWS CDK), or Terraform. This feature is available in all currently supported Amazon MWAA Regions.

On the Amazon MWAA console, simply edit the environment and select an available Apache Airflow version higher than the current version of your existing environment. You can also use the UpdateEnvironment API and specify the new Apache Airflow version to trigger an upgrade process. To learn more about in-place version upgrades, refer to Upgrading the Apache Airflow version from Amazon MWAA documentation.

During an upgrade, Amazon MWAA first creates a snapshot of the existing environment’s metadata database, which then serves as the basis for a new database. Subsequently, all Apache Airflow components—web server, scheduler, and workers—are upgraded. Finally, the newly created metadata database is upgraded, effectively completing the transition to the new environment.

Applicable use cases

You should consider upgrading your Apache Airflow version on Amazon MWAA if your existing workflows can accommodate the change and a new version is available with features or improvements that align with your use case. By upgrading, you can take advantage of the latest capabilities of the Apache Airflow platform and maintain compatibility with new features and best practices like data-driven scheduling and new Amazon provider packages released in Apache Airflow 2.4.3. The upgrade process involves an environment downtime that can take up to 2 hours to complete depending on the environment size and can be performed on demand at a time that best suits you. If your existing environment is heavily used such that you can’t afford a downtime, consider creating a new environment instead.

Prerequisites

When preparing for the upgrade, make sure you complete the following prerequisite steps:

Verify Apache Airflow changes between your existing and new versions of the environment. Review the Apache Airflow release notes to understand the impact of new features, significant changes, and bug fixes that all intermediate Apache Airflow releases made between your source and destination versions.
Review your existing requirements.txt file to verify the correct set of dependencies required for your target environment. Additionally, verify that your requirements.txt file has the correct constraints file added at the top of the file to match your target environment. The Apache Airflow constraints file specifies the dependent modules and provider versions available at the time of an Apache Airflow release. Adding a constraints file prevents incompatible libraries from being installed to your environment. In the following example, replace {Airflow-version} with your target environment’s version number, and {Python-version} with the version of Python that’s compatible with your environment: --constraint "https://raw.githubusercontent.com/apache/airflow/constraints-{Airflow-version}/constraints-{Python-version}.txt"
Review the compatibility of additional Python libraries mentioned in your requirements.txt file to match your target environment. Apache Airflow v2.4.3 and above use Python v3.10, while older Apache Airflow versions use Python v3.7. Therefore, if you are trying to upgrade your existing Apache Airflow v2.0.2/2.2.2-based environment to Apache Airflow v2.4.3 or higher, you should update your additional Python libraries to match Python v3.10.
With Apache Airflow v2.4.3 and above, the list of provider packages Amazon MWAA installs by default for your environment has changed. Note that some imports and operator names have changed in the new provider package in Apache Airflow in order to standardize the naming convention across the provider packages. Compare the list of provider packages installed by default in Apache Airflow v2.2.2 or v2.0.2, and configure any additional packages you might need for your new Apache Airflow v2.4.3 and higher environment.
Make sure that your DAGs and other workflow resources are compatible with the new Apache Airflow version you are upgrading to.
Use the aws-mwaa-local-runner utility to test out your existing DAGs, requirements, plugins, and dependencies locally before deploying to Amazon MWAA. You can create a target Apache Airflow environment that’s similar to an Amazon MWAA production image locally using aws-mwaa-local-runner and verify all your components work before attempting to upgrade your Amazon MWAA environment. Additionally, test the new environment upgrade process in lower Amazon MWAA environments like dev or staging before rolling out the upgrade in production environments.

Upgrade process

When an upgrade has been initiated, Amazon MWAA stops the existing underlying Apache Airflow components (web server, scheduler, and workers). This process halts any worker tasks that are currently running. The status of your environment at this stage will show as UPDATING. The upgrade process then creates a database snapshot of the metadata database, marked by the status CREATING_SNAPSHOT. When the snapshot is complete, the environment status returns to UPDATING as Amazon MWAA triggers the creation of a new Apache Airflow environment that matches your version selection and applies the necessary schema changes to the existing metadata database to align it with the target Apache Airflow environment. During this phase, your specified requirements, plugins, and other dependencies are installed.

Upon completion, your new environment is marked as AVAILABLE, indicating that the upgrade process has been successful and the environment is ready for testing. You can now log in to your Apache Airflow UI to verify the presence of your existing DAGs, their historical runs, configured connections, and more.

However, if there are failures in installing your specified requirements, plugins, and dependencies files, the environment initiates a rollback to the previous stable version. During this process, your environment status will show as ROLLING_BACK. If the rollback is successful, your previous stable environment will be available and the status will display as UPDATE_FAILED until a new update is attempted and succeeds. If the rollback fails, the status will show as UNAVAILABLE, indicating that your environment is not functional.

If your environment upgrade process fails, it is likely that the underlying Amazon Elastic Container Service (Amazon ECS) AWS Fargate clusters had stabilization issues caused by conflicting requirements and plugins, networking issues, or DB migration issues after the Apache Airflow component upgrade. To mitigate these issues, ensure that your DAGs and requirements work without issues using the aws-mwaa-local-runner utility and, ideally, test in a staging Amazon MWAA environment.

Additional considerations

Keep in mind the following additional information of this feature:

The upgrade process is available on demand, and will be limited to moving to newer versions. In-place version upgrades on Amazon MWAA are not supported for version 1.10.z. To perform a major version upgrade, for example from version 1.y.z to 2.y.z, you must create a new environment and migrate your resources.
You can only select applicable higher versions that you can upgrade to. Downgrading to a lower version is not available.
The rollback process can take additional time and, if you have Amazon Simple Storage Service (Amazon S3) bucket versioning enabled, Amazon MWAA is designed to revert the environment to the previous working configuration, including plugins and requirements. However, any manual changes made to your DAGs will not be reverted during this process.
After the upgrade process has completed successfully and the environment is available, any running DAGs that were interrupted during the upgrade are scheduled for a retry, depending on the way you configure retries for your DAGs. You can also trigger them manually or wait for the next scheduled run.
You should iteratively upgrade your environments starting with the least critical ones first.

Conclusion

In this post, we talked about the new feature of Amazon MWAA that allows you to upgrade your existing Amazon MWAA environment to higher Apache Airflow versions. This feature is supported on new and existing Amazon MWAA environments running Apache Airflow 2.x and above. Use this feature to upgrade your Apache Airflow versions while retaining your existing workflow run histories and environment configurations. By upgrading, you can take advantage of the latest capabilities of the Apache Airflow platform and maintain compatibility with new features and adhere to best practices.

For additional details and code examples on Amazon MWAA, visit the Amazon MWAA User Guide and the Amazon MWAA examples GitHub repo.

Apache, Apache Airflow, and Airflow are either registered trademarks or trademarks of the Apache Software Foundation in the United States and/or other countries.

About the Authors

Parnab Basak is a Solutions Architect and a Serverless Specialist at AWS. He specializes in creating new solutions that are cloud native using modern software development practices like serverless, DevOps, and analytics. Parnab works closely in the analytics and integration services space helping customers adopt AWS services for their workflow orchestration needs.

Fernando Gamero is a Senior Solutions Architect engineer at AWS, having more than 25 years of experience in the technology industry, from telecommunications, banking to startups. He is now helping customers with building Event Driven Architectures, adopting IoT solutions at the Edge, and transforming their data and machine learning pipelines at scale.

Shubham Mehta is an experienced product manager with over eight years of experience and a proven track record of delivering successful products. In his current role as a Senior Product Manager at AWS, he oversees Amazon Managed Workflows for Apache Airflow (Amazon MWAA) and spearheads the Apache Airflow open-source contributions to further enhance the product’s functionality.

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