Page History

...

The movers are standalone processes, and communicate with the agent using gRPC, an RPC protocol built using Google's Protocol Buffers.  When the agent starts, it starts the configured movers automatically. 

Agent

The Agent interacts with the Lustre coordinator and forwards messages to the data movers. It also provides additional functionality that is needed for all movers:

• Stores the HSM key provided by the mover. Currently the agent stores the key as opaque data in a trusted extended attribute. In the future this key might be stored in the layout or else where in the file’s metadata, though this is transparent to the data movers.

• Restore file striping metadata. When a restore operation is received, the agent ensures the striping information on the original file is used when the data is restored. Although Lustre does not support this currently, in the future users (or a policy engine) will be update the striping data before restoring the file.
• Capture and log metric data on operation of the agent and data movers.

RPC Interface

service DataMover {
    rpc Register(Endpoint) returns (Handle);
    rpc GetActions(Handle) returns (stream ActionItem);
    rpc StatusStream(stream ActionStatus) returns (Empty);
}

...