Replatform a monolith that uses a shared configuration file accessed concurrently by multiple instances without changing application code. Which storage solution requires minimal changes?

Filestore provides a fully managed NFS file share service, which is ideal for applications requiring shared file system access like your monolith's configuration file. Mounting it as an NFS-backed PersistentVolume in Kubernetes allows multiple instances to concurrently access the configuration without application code changes, directly addressing the requirement. Cloud Storage buckets mounted via gcsfuse are object storage, not a true shared file system, and may introduce latency or consistency issues for concurrent access patterns expected by a monolith. A new Persistent Disk is typically block storage and cannot be shared concurrently by multiple instances without complex, application-level coordination or specific shared disk solutions not natively supported by standard Persistent Disks. ConfigMaps are suitable for small, non-changing configuration data, but they are not designed for shared file access patterns and have size limitations, making them less suitable for a shared configuration file that might be updated or accessed like a traditional file system.