Architecture of Nublado controller¶

The Nublado controller is a FastAPI application with three basic functions:

Prepull images to every Kubernetes node.
Manage user lab pods and their supporting environment.
Manage user file server pods and their supporting environment.

Internally, the code structure uses the handler-services-storage code structure documented in SQR-072. To try to keep the size of the major services, such as the user lab manager, manageable, there are several layers of services that coordinate.

This diagram attempts to provide a guide to the overall code structure. The Kubernetes storage layer is further subdivided into per-resource storage layers, which are not shown in this graph to try to keep the graph more concise.

        flowchart LR
  subgraph services
    prepuller(Prepuller)
    image(ImageService)
    lab(LabManager)
    fileserver(FileserverManager)
    image --> docker-source(DockerImageSource)
    image --> gar-source(GARImageSource)
    prepuller --> prepull-builder(PrepullerBuilder)
    prepuller --> image
    lab --> image
    lab --> lab-builder(LabBuilder)
    fileserver --> fileserver-builder(FileserverBuilder)
    lab-builder --> volume-builder(VolumeBuilder)
    fileserver-builder --> volume-builder
  end
  subgraph storage
    docker(DockerStorageClient)
    gar(GARStorageClient)
    metadata(MetadataStorage)
    fileserver-storage(FilserverStorage)
    fileserver-storage --> kubernetes(Kubernetes)
    lab-storage(LabStorage)
    lab-storage --> kubernetes
    node-storage(NodeStorage)
  end
  docker-source --> docker
  gar-source --> gar
  fileserver --> fileserver-storage
  lab --> metadata
  lab --> lab-storage
  prepuller --> metadata
  prepuller --> kubernetes
  image --> node-storage

  main(app) --> handlers
  handlers --> image
  handlers --> prepuller
  handlers --> lab
  handlers --> fileserver
  background(BackgroundTaskManager)
  background --> image
  background --> prepuller
  background --> lab
  background --> fileserver

Internal structure¶