This is a production-grade Kubernetes CSI (Container Storage Interface) driver for JuiceFS, a cloud-native distributed POSIX filesystem. It enables dynamic and static provisioning of JuiceFS volumes as Kubernetes PersistentVolumes. The system consists of multiple microservices running in a Kubernetes cluster: a CSI Controller (StatefulSet) that handles volume creation, deletion, expansion, and snapshots; a CSI Node (DaemonSet) that manages mount and unmount operations; an optional webhook component for sidecar injection and validation; and a Dashboard (Deployment+React frontend) for management and troubleshooting. It supports three mount modes: default mount-pod (dedicated pod for JuiceFS client), sidecar (inject into application pod via mutating webhook), and process (deprecated). The codebase demonstrates a strong command of Kubernetes controller patterns, with sophisticated features like graceful upgrade of mount pods via FUSE file descriptor passing, time-ordered caching for dashboard APIs, and a builder pattern for mount pod creation. The architecture is well-modularized but has a large configuration surface.
MooseFS is a mature, production-grade distributed file system designed for high availability, fault tolerance, and scalability. Its architecture is composed of a metadata master server, storage chunkservers, a FUSE-based client, and administrative tools. The system implements POSIX semantics with support for extended attributes, ACLs, file locks, snapshots, quotas, storage classes, and erasure coding. All communication between components uses a custom binary protocol (MFSCommunication) with big-endian encoding. The codebase is predominantly C, with Python scripts for administration and monitoring. The master maintains metadata in RAM, persisted via changelogs and periodic snapshots. Chunk replication is configurable via goals and label-based topology. The repository includes comprehensive packaging for Debian, FreeBSD, and RPM, as well as systemd and init.d service files. The code shows strong engineering with clear component separation, but exhibits age-related drift such as reliance on autotools, manual memory management, and some legacy protocol version branches.