Core Concepts

This section describes the core concepts of MPAS and what Kubernetes controllers and custom resources are contained. To learn more about the MPAS architecture, see Architecture.

Product#

A Product is a package of software that can be deployed to target environments such as Kubernetes clusters, virtual machines or bare-metal devices.

Products are made available to the MPAS system as OCM Components via a Subscription. Multiple instances of a Product may be installed that refer to the same Subscription.

A ProductDeployment is a Kubernetes Custom Resource that represents a product to be deployed to a target. The ProductDeployment is reconciled by the MPAS Product Controller which will generate the necessary Kubernetes resources to deploy the product to the cluster.

A ProductDeploymentGenerator is a Kubernetes Custom Resource that represents a ProductDeployment to be deployed to a Kubernetes cluster. The ProductDeploymentGenerator is reconciled by the MPAS Product Controller in order to generate the ProductDeployment resource.

A ProductDescription is a manifest that describes a product. It specifies the set of resources that are needed to deploy the product in a form of pipeline steps. The ProductDescription is retrieved by the MPAS Product Controller in order to generate the ProductDeployment resource during a ProductDeploymentGenerator reconciliation.

A ProductDeploymentPipeline is a Kubernetes Custom Resource that defines a resource that needs to be deployed as part of the ProductDeployment. The ProductDeploymentPipeline is reconciled by the MPAS Product Controller as part of the ProductDeployment deployment.

Project#

A Project is a Kubernetes Custom Resource that is used to manage the lifecycle of a MPAS project. A Project is reconciled by the MPAS Project Controller which will generate a project namespace and a git repository for the project containing the project folder structure. The controller will also generate the necessary Flux kustomization resources in the mpas-system namespace in order to update the cluster with the project resources from the git repository. All items that the MPAS Project Controller created during reconcile, are visible in the status subresource of a Project CR.

The project git repository is designed to be used as a GitOps repository for the project. It contains all the product custom resources in order to be deployed to the cluster.

Subscription#

The purpose of a Subscription is to replicate OCM components containing a particular product from a delivery registry into a target registry in the MPAS customer’s environment.

A ComponentSubscription is a Kubernetes Custom Resource that represents a subscription to a component. The ComponentSubscription is reconciled by the Replication Controller which will transfer the OCM component into the target registry using the OCM library.

Target#

A Target is a Kubernetes Custom Resource that represents a target environment where a Product should be deployed. The MPAS Product Controller controller reconciles the Target and creates any necessary prerequisite that needs to exist in the target environment, e.g. a namespace and a service account.