csi.md

CSI in Mayastor

CSI is a storage provider gRPC interface independent of storage vendor and cloud environment. The reader should be familiar with CSI spec before reading this document.

Basic workflow starting from registration is as follows:

1. csi-node-driver-registrar retrieves information about csi plugin (mayastor) using csi identity service.
2. csi-node-driver-registrar registers csi plugin with kubelet passing plugin's csi endpoint as parameter.
3. kubelet uses csi identity and node services to retrieve information about the plugin (including plugin's ID string).
4. kubelet creates a custom resource (CR) "csi node info" for the CSI plugin.
5. kubelet issues requests to publish/unpublish and stage/unstage volume to the CSI plugin when mounting the volume.

The registration of the storage nodes (i/o engines) with the control plane is handled by a gRPC service which is independent of the CSI plugin.

graph LR
;
    PublicApi{"Public<br>API"}
    CO[["Container<br>Orchestrator"]]

    subgraph "Mayastor Control-Plane"
        Rest["Rest"]
        InternalApi["Internal<br>API"]
        InternalServices["Agents"]
    end

    subgraph "Mayastor Data-Plane"
        IO_Node_1["Node 1"]
    end

    subgraph "Mayastor CSI"
        Controller["Controller<br>Plugin"]
        Node_1["Node<br>Plugin"]
    end

%% Connections
    CO -.-> Node_1
    CO -.-> Controller
    Controller -->|REST/http| PublicApi
    PublicApi -.-> Rest
    Rest -->|gRPC| InternalApi
    InternalApi -.->|gRPC| InternalServices
    Node_1 <--> PublicApi
    Node_1 -.->|NVMe-oF| IO_Node_1
    IO_Node_1 <-->|gRPC| InternalServices

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