helm-dependency-submodules

Demonstrates the usage of Git submodules as Helm dependencies

Overview

Helm has a concept of dependencies to manage the deployment of multiple charts. While this is typically accomplished by referencing a subchart from a helm repository, subcharts can also be referenced from the file system. Instead of copying the contents directly, a reference to an existing Git repository can be made using Git submodules.

The Helm chart contained within this repository will deploy a simple Quarkus based application that is contained within a submodule consisting of a set of Helm charts from the Red Hat Developers team.

Installation and Deployment

The following sections describe the various way in which the chart can be deployed:

Standalone

First clone the repository for your machine and change into the repository directory:

git clone --recurse-submodules https://github.com/sabre1041/helm-dependency-submodules
cd helm-dependency-submodules

Note: The use of the the --recurse-submodules flag will automatically initialize the submodule and update the content to the associated commit.

Update the Helm dependencies from the chart located in the submodule

helm dependency update

Create a new Helm release in a new namespace called 'helm-dependency-submodules-standalone`:

helm upgrade -i --create-namespace -n helm-dependency-submodules-standalone quarkus .

Confirm the application is running

kubectl get pods -n helm-dependency-submodules-standalone

Navigate to the application

kubectl get routes -n helm-dependency-submodules-standalone -o jsonpath='https://{ .items[*].spec.host }'

ArgoCD

The deployment of the chart also be facilitated using a GitOps tool, such as ArgoCD.

Important: ArgoCD tracks applications using the app.kubernetes.io/instance annotation on resources. If both the standalone method as described above and ArgoCD facilitates the deployment with the same name on the same cluster (even in different namespaces [in cluster level mode]), the ArgoCD application will appear to be out of sync. To mitigate this issue, set the application.instanceLabelKey in the argocd-cm ConfigMap or the spec.applicationInstanceLabelKey: when using the ArgoCD operator to the value of argocd.argoproj.io/instance.

Deploy the instance of ArgoCD with access to create resources across the cluster.

Apply the Application resource which will deploy the Chart to a namespace called helm-dependency-submodules-argocd.

kubectl apply -n <argocd_namespace> -f argocd/application.yaml

Confirm the application has been deployed and is running

kubectl get pods -n helm-dependency-submodules-argocd

Navigate to the application

kubectl get routes -n helm-dependency-submodules-argocd -o jsonpath='https://{ .items[*].spec.host }'