Sad to see flexVolume deprecated. CSI is a more powerful interface and I knew this was coming, but the simplicity of the flexVolume exec model for node-local volumes was an amazing feature.

With very little effort, you could use them to create volumes managed by any binary or script: for example, a volume that fetches internal build artifacts or a volume similar to configmaps that pulls from external data sources on pod startup.

The new CSI interface requires operating a GRPC server on a local unix socket. It'd have been great if it were at least HTTP+JSON. GRPC really increases the barrier to entry in all languages that can't use the golang CSI driver libraries and it's hard to see the advantages for a low volume API on localhost.