Experience Building and Operating a Personalized Airflow Testing Environment (opens in new tab)
Kakao’s data engineering team built AirZone to make Airflow DAG testing faster, easier, and safer across an ecosystem containing thousands of DAGs and multiple Hadoop clusters. Existing approaches required local setup, repeated Git synchronization, file copying, VPN access, or risky testing on production Airflow. AirZone instead creates an isolated, production-like Airflow environment for each pull request, managed through GitHub comments and Kubernetes automation. ## Limitations of Existing Testing Methods - **Local Airflow** - Requires configuring Airflow, Hadoop authentication, connections, and Docker locally. - Has a high initial setup cost and may differ from production. - **Development Airflow** - Requires committing and pushing every code change. - Git submodule updates and DAG parsing introduce long feedback delays. - **Test Airflow with SSH** - Allows files to be copied directly into a container. - Still requires copying files after every edit. - Access to production Hadoop requires connecting to a production VPN. - **Testing on production Airflow** - Heavy test DAGs consume shared scheduler, worker, and node resources. - A resource-intensive test can delay or interrupt unrelated projects. - Per-user isolation is therefore essential. ## AirZone Requirements - Provide an Airflow environment without requiring users to understand Kubernetes or Helm. - Allow code editing through a browser using Jupyter Notebook. - Execute DAGs against Hadoop and authentication mechanisms similar to production. - Create an independent environment for each pull request. - Prevent one user’s tests from affecting other workflows. ## PR-Based, Isolated Architecture - GitHub pull request comments serve as the user interface. - Users can create or delete an environment directly from a PR. - The resulting environment link is posted back to the PR. - Each PR receives a dedicated Kubernetes namespace based on the repository and PR number. - Airflow web server, scheduler, PostgreSQL, Jupyter, DAG volumes, and logs are isolated. - Multiple PRs can be tested simultaneously. - Cleanup is straightforward because the namespace defines the environment boundary. - A dedicated AirZone Helm chart packages the complete test environment. - Production-only components such as PGBouncer and external database connections are omitted where unnecessary. - Airflow, PostgreSQL, DAG storage, Jupyter, authentication, TLS, and logging are deployed together. ## Separating Requests from Deployment - `airzone-api` only validates requests: - Confirms that the PR exists and is open. - Checks branch information. - Prevents duplicate namespaces. - Kubernetes Jobs perform the long-running work: - Install the Helm release. - Run health checks. - Handle creation and deletion independently from the API process. - Job names include the operation and namespace, such as: - `create-airzone-{namespace}` - `delete-airzone-{namespace}` - Failed Jobs can be removed and recreated for retries. - Independent Job logs and status make deployment failures easier to diagnose. - A daily CronJob removes environments that remain after their PRs are closed. ## Building the Airflow Environment Each Helm deployment includes the components needed for a realistic test environment: - **Git integration:** Synchronizes the PR’s head repository and branch. - **DAG PVC:** Lets the scheduler and Jupyter use the same working directory. - **Airflow configuration:** Uses KubernetesExecutor and test-specific DAG scanning, logging, and Hadoop settings. - **Authentication:** Injects user and shared principals, keytabs, Jupyter tokens, and TLS certificates. - **Infrastructure placement:** Selects suitable node groups and a storage class in the same region. - **Centralized logging:** Connects Airflow logs to Elasticsearch and Kibana. - **Hadoop execution:** Existing infrastructure runs Hadoop tasks in dedicated pods using custom Hadoop images, Kerberos initialization, Spark, and Hive. ## Notifications and Security - KakaoWork sends: - An initial notification when a request is received. - A completion notification after deployment. - Operational error alerts. - Sensitive information, including Jupyter and Kubernetes namespace tokens, is not posted in public PR comments. - Tokens are delivered through KakaoWork instead, keeping authentication data separate from the broader PR audience. AirZone’s main recommendation is to make testing a disposable, reproducible environment tied to the pull request itself. By combining per-PR Kubernetes namespaces, Helm-based deployment, asynchronous Jobs, production-like Hadoop access, and automatic cleanup, teams can test DAGs quickly without burdening shared Airflow or production resources.