Installing the chart

Prerequisites

• Kubernetes 1.20+
• Helm 3.8.0+

Installation steps

All examples in this guide use the public chart and images. If you've mirrored the repository for your own use (for example, to your Docker Hub namespace), update your commands to reference the mirrored chart instead of the public one.

For example:

• Public chart: dhi.io/<repository>:<tag>
• Mirrored chart: <your-namespace>/dhi-<repository>:<tag>

For more details about customizing the chart to reference other images, see the documentation⁠.

Step 1: Optional. Mirror the Helm chart and/or its images to your own registry

To optionally mirror a chart to your own third-party registry, you can follow the instructions in How to mirror an image ⁠ for either the chart, the image, or both.

The same regctl tool that is used for mirroring container images can also be used for mirroring Helm charts, as Helm charts are OCI artifacts.

For example:

 regctl image copy \
     "${SRC_CHART_REPO}:${TAG}" \
     "${DEST_REG}/${DEST_CHART_REPO}:${TAG}" \
     --referrers \
     --referrers-src "${SRC_ATT_REPO}" \
     --referrers-tgt "${DEST_REG}/${DEST_CHART_REPO}" \
     --force-recursive

Step 2: Create a Kubernetes secret for pulling images

The Docker Hardened Images that the chart uses require authentication. To allow your Kubernetes cluster to pull those images, you need to create a Kubernetes secret with your Docker Hub credentials or with the credentials for your own registry.

Follow the authentication instructions for DHI in Kubernetes⁠.

For example:

kubectl create secret docker-registry helm-pull-secret \
  --docker-server=dhi.io \
  --docker-username=<Docker username> \
  --docker-password=<Docker token> \
  --docker-email=<Docker email>

Step 3: Install the Helm chart

To install the chart, use helm install. Make sure you use helm login to log in before running helm install. Optionally, you can also use the --dry-run flag to test the installation without actually installing anything.

The --set path below (global.image.pullSecretNames[0]) matches the pull-secret key the chart's StatefulSet and nats-box Deployment templates read (.Values.global.image.pullSecretNames).

helm install my-nats oci://dhi.io/nats-chart --version <version> \
  --set "global.image.pullSecretNames[0]=helm-pull-secret"

Replace <version> accordingly. If the chart is in your own registry or repository, replace dhi.io with your own registry and namespace. Replace helm-pull-secret with the name of the image pull secret you created earlier.

Step 4: Verify the installation

The StatefulSet pod should show up and become ready shortly after install:

$ kubectl get pods
NAME         READY   STATUS    RESTARTS   AGE
my-nats-0    2/2     Running   0          30s

2/2 includes the NATS server container and the config-reloader sidecar. A nats-box Deployment is also created for CLI access (kubectl exec). Port-forward the client port and check the monitoring endpoint:

kubectl port-forward svc/my-nats 4222:4222 8222:8222
curl -s http://127.0.0.1:8222/varz | head

To enable the Prometheus metrics sidecar (uses dhi/prometheus-nats-exporter):

helm upgrade my-nats oci://dhi.io/nats-chart --version <version> \
  --set "global.image.pullSecretNames[0]=helm-pull-secret" \
  --set "promExporter.enabled=true"