Helm¶

Currently we are only using Helm for templating. Therefore only the client is required (Tiller as the server-side component is not required).

Install Helm client¶

There are several possibilities how to install Helm. One of them is by using a script:

curl https://raw.githubusercontent.com/helm/helm/master/scripts/get > get_helm.sh
chmod 700 get_helm.sh
./get_helm.sh

To initialize Helm without installing Tiller on your cluster, use

helm init --client-only

Templating with Helm¶

Fetching the chart templates (helm fetch)
Rendering the template with configurable values (helm template)
Applying the result to the cluster (kubectl apply)

Istio¶

Helm is great for templating. Escpecially for creating an adapted Istio installation. The official Istio installation steps also recommends the usage of using helm template.

For more information see section Istio.

Setup Helm & Tiller¶

Like already mentioned, Tiller is currently not used!

(https://docs.microsoft.com/en-us/azure/aks/kubernetes-helm)

Install Helm on your local machine (https://github.com/helm/helm#install)

Create a service account and an according role-binding for Tiller (necessary in a RBAC-enabled cluster).

helm-rbac.yaml:

apiVersion: v1
kind: ServiceAccount
metadata:
name: tiller
namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
name: tiller
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: cluster-admin
subjects:
- kind: ServiceAccount
    name: tiller
    namespace: kube-system

Apply it to Kubernetes with:
```
kubectl apply -f helm-rbac.yaml
```

Alternatively via command-line:

kubectl create serviceaccount --namespace kube-system tiller \
kubectl create clusterrolebinding tiller-cluster-rule --clusterrole=cluster-admin --serviceaccount=kube-system:tiller \
helm init --service-account tiller --upgrade

Troubleshooting¶

Getting error Error: found in requirements.yaml, but missing in charts/ directory: …

Update dependencies (Istio in version 1.1.0-snapshot.4 is used):

helm init --client-only
helm repo add istio.io https://storage.googleapis.com/istio-release/releases/1.1.0-snapshot.4/charts
helm dependency update install/kubernetes/helm/istio