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IRI - IronCore Runtime Interface

Introduction

The IronCore Runtime Interface (IRI) is a GRPC-based abstraction layer introduced to ease the implementation of a poollet and pool provider.

A poollet does not have any knowledge how the resources are materialized and where the pool provider runs. The responsibility of the poollet is to collect and resolve the needed dependencies to materialize a resource.

A pool provider implements the IRI, where the IRI defines the correct creation and management of resources handled by a pool provider. A pool provider of the IRI should follow the interface defined in the IRI APIs. 

graph LR
    P[poollet] --> IRI
    IRI{IRI} --> B
    B[pool provider]

pool provider

A pool provider represents a specific implementation of resources managed by a Pool. The implementation details of the pool provider depend on the type of resource it handles, such as Compute or Storage resources.

Based on the implementation of a pool provider it can serve multiple use-cases: - to broker resources between different clusters e.g. volume-broker - to materialize resources e.g. block devices created in a Ceph cluster via the cephlet

Interface Methods

The IRI defines several interface methods categIRIzed into Compute, Storage, and Bucket.

The IRI definition can be extended in the future with new resource groups.

Diagram

Below is a diagram illustrating the relationship between poollets, IRI, and pool providers in the ironcore project.

graph TB
    A[Machine] -- scheduled on --> B[MachinePool]
    C[Volume] -- scheduled on --> D[VolumePool]
    B -- announced by --> E[machinepoollet]
    D -- announced by --> F[volumepoollet]
    E -- GRPC calls --> G[IRI compute provider]
    F -- GRPC calls --> H[IRI storage provider]
    G -.sidecar to.- E
    H -.sidecar to.- F

This diagram illustrates:

  • Machine resources are scheduled on a MachinePool which is announced by the machinepoollet.
  • Similarly, Volume resources are scheduled on a VolumePool which is announced by the volumepoollet.
  • The machinepoollet and volumepoollet each have an IRI provider sidecar, which provides a GRPC interface for making calls to create, update, or delete resources.
  • The IRI provider (Compute) is a sidecar to the machinepoollet and the IRI provider (Storage) is a sidecar to the volumepoollet. They handle GRPC calls from their respective poollets and interact with the actual resources.