Everyone hates NFS yet everyone uses NFS

(written by lawrence krubner, however indented passages are often quotes). You can contact lawrence at: lawrence@krubner.com, or follow me on Twitter.

For more than 10 years I’ve heard people tell me that NFS is obsolete and no sensible engineer would ever use it. Nevertheless, it remains useful and so engineers use it:

After some experimentation we found that we could vastly improve performance across our Airflow environments by running an NFS (network file system) server within the Kubernetes cluster. We then mounted this NFS server as a read-write-many volume into the worker and scheduler pods. We wrote a custom script which synchronizes the state of this volume with  GCS, so that users only have to interact with GCS for uploading or managing DAGs. This script runs in a separate pod within the same cluster. This also allows us to conditionally sync only a subset of the DAGs from a given bucket, or even sync DAGs from multiple buckets into a single file system based on the environment’s configuration (more on this later).

Altogether this provides us with fast file access as a stable, external source of truth, while maintaining our ability to quickly add or modify DAG files within Airflow. Additionally, we can use Google Cloud Platform’s IAM (identify and access management) capabilities to control which users are able to upload files to a given environment. For example, we allow users to upload DAGs directly to the staging environment but limit production environment uploads to our continuous deployment processes.

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