IBM Multicloud Manager application resource overview

An IBM Multicloud Manager application consists of five application resources, which are defined as Application, Deployable, PlacementPolicy, DeployableOverride, and ApplicationRelationship.

Application specification

A cluster application is defined with the Kubernetes SIG Application CRD community specification. A multi-cluster application uses the same Kubernetes specification, but with additional automation of the deployment and life-cycle management of resources to individual clusters.

Application resource examples

View and deploy applications with the five resources. Your Application is used to only view your resource, while the other four application resource examples are for deployment.

Application resource

View your resource with an Application resource. See the following example of the definition for an Application.

Edit the spec section of your YAML to define your application with labels. The Application spec groups resources in componentKinds based on the selector. See the following sample, where Service, Deployment and Statefulset, with the app: details label are grouped into the Application details-app:

  apiVersion: mcm.ibm.com/v1alpha1
  kind: Application
  metadata:
    name: details-app
    labels:
      app: details
  spec:
    selector:
      matchLabels:
        app: details
    componentKinds:
    - group: core
      kind: Service
    - group: apps
      kind: Deployment
    - group: apps
      kind: StatefulSet

Deployable

A Deployable resource deploys your Helm chart.

Edit the spec section of your YAML to define your application. See the following sample Deployable spec, which defines the Helm chart as a deployable resource. Here, chartName, nginx-lego, and chartVersion, 0.3.1, are in the google repository. The placementPolicy defines the deployment criteria.

  apiVersion: mcm.ibm.com/v1alpha1
  kind: Deployable
  metadata:
    name: trader
    labels:
      serviceKind: ApplicationService
      name: trader
      placementPolicy: "trader"
  spec:
    deployer:
      kind: helm
      helm:
        repository: google
        chartName: nginx-lego
        chartVersion: 0.3.1

PlacementPolicy

PlacementPolicy defines the criteria to find cluster(s) to place or deploy workloads. For example, if you create a PlacementPolicy, add or remove a cluster, or if your cluster compliance changes, IBM Multicloud Manager generates a new list of target clusters based on those changes. If more than one cluster matches that criteria, then IBM Multicloud Manager uses resourceHint as criteria, then deletes what is no longer valid.

Edit the spec section of your YAML to define your PlacementPolicy. See the following sample PlacementPolicy that defines a cluster with purpose as prod, and resourceHint defined as cpu so that IBM Multicloud Manager chooses the cluster with the most available CPU cores.

  apiVersion: mcm.ibm.com/v1alpha1
  kind: PlacementPolicy
  metadata:
    name: trader        
  spec:
    replicas: 1
    clusterLabels:
      matchLabels:
        purpose: prod
    resourceHint:
      type: cpu
      order: desc

DeployableOverride

DeployableOverride is used to define different values from the original Deployable and override a deployment.

Edit the spec section of your YAML to define your DeployableOverride. Any value in the spec template can be different from the original Deployable.

See the following sample, where deployer is defined for production cluster and for test cluster. The sample file contains the same Helm chartName and chartVersion, but different repository values to deploy to a cluster.

  apiVersion: mcm.ibm.com/v1alpha1
  kind: DeployableOverride
  metadata:
    name: trader
  spec:
    overrides:
    - clustername: productioncluster
      namespace: default
      template:
          deployer:
            kind: helm
            helm:
              repository: production-repo
              chartName: app-chart
              chartVersion: 0.11.0
              values: somevalues
    - clustername: testcluster
      namespace: default
      template:
          deployer:
            kind: helm
            helm:
              repository: test-repo
              chartName: app-chart
              chartVersion: 0.11.0
              values: someothervalues

ApplicationRelationship

ApplicationRelationship deploys an application on another application based on the source and destination values.

Edit the spec section of your YAML to define your application. The following sample shows the definition for the details of the ApplicationRelationship, where Deployable product-app depends on Deployable details-app, and the two are deployed together.

  apiVersion: mcm.ibm.com/v1alpha1
  kind: ApplicationRelationship
  metadata:
      name: product-to-details
      labels:
        app: productpage
  spec:
    type: usesCreated
    source:
      clustername: crucial-owl
      kind: Deployable
      name: product-app
      namespace: default
    destination:
      kind: Deployable
      name: details-app
      clustername: crucial-owl
      namespace: default

See Creating IBM Multicloud Manager application resources to learn how to create application resources.

Then, see Working with IBM Multicloud Manager applications for more application topics.