Add app deploy scenario (#7)

Signed-off-by: Jian Qiu <jqiu@redhat.com>

README.md

@@ -33,7 +33,8 @@ In addition, developers can leverage [Addon framework](https://github.com/open-c
 * Centrally create, update, and delete Kubernetes clusters across multiple private and public clouds.
 * Automatically deploy applications to specific clusters by subscribing to different workload (resource) channels, such as GitHub, Helm repository, ObjectStore, and resource templates.
 
-The application model defines a Kubernetes-first way of describing the application. Your existing Kubernetes apps or `kustomized` apps can be adapted with the addition of a few new objects: [Channel](https://github.com/open-cluster-management-io/multicloud-operators-channel), and [Subscription](https://github.com/open-cluster-management-io/multicloud-operators-subscription). Changes made to the app are then easily delivered to managed clusters based on the dynamic placement engine.
+The application model defines a Kubernetes-first way of describing the application. Your existing Kubernetes apps or `kustomized` apps can be adapted with the addition of a few new objects: [Channel](https://github.com/open-cluster-management-io/multicloud-operators-channel), and [Subscription](https://github.com/open-cluster-management-io/multicloud-operators-subscription). Changes made to the app are then easily delivered to managed clusters based on the dynamic placement engine. See [deploy a helm chart][solutions/deploy-a-helm-chart] on how
+to install application manager addon in OCM and deploy helm charts in multiple clusters.
 
 ### GRC: Governance, Risk and Compliance across Kubernetes clusters
 

solutions/deploy-a-helm-chart/READEME.md

@@ -0,0 +1,37 @@
+# Deploy a Helm Chart
+
+## Prerequisite
+
+Set up the dev environment in your local machine following [setup dev environment](../setup-dev-environment).
+
+## Install application addon on OCM
+
+Install application manager addon on the hub cluster
+
+```
+kubectl config use kind-hub
+clusteradm install addons --names application-manager
+```
+
+Install application manager agent on all the managed clusters
+
+```
+clusteradm enable addons --names application-manager --clusters cluster1,cluster2
+```
+
+You will see that all agents is available after waiting a while
+
+```
+$ kubectl get managedclusteraddon --all-namespaces
+NAMESPACE   NAME                  AVAILABLE   DEGRADED   PROGRESSING
+cluster1    application-manager   True
+cluster2    application-manager   True
+```
+
+## Deploy a helm chart to cluster1
+
+Run `./deploy.sh` to deploy the helm chart on cluster1
+
+It will create a [channel](manifests/channel.yaml) which specifies a helm repo, a [placement](manifests/placement.yaml)
+to select one or multiple clusters, and a [subscription](manifests/subscription.yaml) to deploy the helm chart. Try
+update `placement` to see how the chart deployment is changed.

solutions/deploy-a-helm-chart/deploy.sh

@@ -0,0 +1,22 @@
+#!/bin/bash
+
+cd $(dirname ${BASH_SOURCE})
+
+set -e
+
+hubctx="kind-hub"
+
+kubectl config use ${hubctx}
+
+echo "Add cluster1, cluster2 to the clusterset"
+
+kubectl label managedcluster cluster1 cluster.open-cluster-management.io/clusterset=app-demo --overwrite
+kubectl label managedcluster cluster2 cluster.open-cluster-management.io/clusterset=app-demo --overwrite
+
+echo "Label cluster1 so placement will select cluster1 only"
+
+kubectl label managedcluster cluster1 purpose=test --overwrite
+
+echo "Deploy the application with placement"
+
+kubectl apply -f manifests/

solutions/deploy-a-helm-chart/manifests/channel.yaml

@@ -0,0 +1,9 @@
+apiVersion: apps.open-cluster-management.io/v1
+kind: Channel
+metadata:
+  name: demo-helmrepo
+  namespace: default
+spec:
+    type: HelmRepo
+    pathname: https://charts.helm.sh/stable/
+    insecureSkipVerify: true

solutions/deploy-a-helm-chart/manifests/clusterset.yaml

@@ -0,0 +1,4 @@
+apiVersion: cluster.open-cluster-management.io/v1alpha1
+kind: ManagedClusterSet
+metadata:
+  name: app-demo

solutions/deploy-a-helm-chart/manifests/clustersetbinding.yaml

@@ -0,0 +1,7 @@
+apiVersion: cluster.open-cluster-management.io/v1alpha1
+kind: ManagedClusterSetBinding
+metadata:
+  name: app-demo
+  namespace: default
+spec:
+  clusterSet: app-demo

solutions/deploy-a-helm-chart/manifests/placement.yaml

@@ -0,0 +1,14 @@
+apiVersion: cluster.open-cluster-management.io/v1alpha1
+kind: Placement
+metadata:
+  name: demo-placement
+  namespace: default
+spec:
+  numberOfClusters: 1
+  clusterSets:
+    - app-demo
+  predicates:
+    - requiredClusterSelector:
+        labelSelector:
+          matchLabels:
+            purpose: test

solutions/deploy-a-helm-chart/manifests/subscription.yaml

@@ -0,0 +1,20 @@
+apiVersion: apps.open-cluster-management.io/v1
+kind: Subscription
+metadata:
+  name: demo-subscription
+  namespace: default
+spec:
+  channel: default/demo-helmrepo
+  name: nginx-ingress
+  placement:
+    placementRef: 
+      name: demo-placement
+      kind: Placement
+  packageOverrides:
+  - packageName: nginx-ingress
+    packageAlias: nginx-ingress-simple
+    packageOverrides:
+    - path: spec
+      value:
+        defaultBackend:
+          replicaCount: 2