Setting up Helm

Helm, the package manager for Kubernetes, is a useful tool for: installing, upgrading and managing applications on a Kubernetes cluster. Helm packages are called charts. We will be installing and managing JupyterHub on our Kubernetes cluster using a Helm chart.

Helm has two parts: a client (helm) and a server (tiller). Tiller runs inside of your Kubernetes cluster as a pod in the kube-system namespace. Tiller manages both, the releases (installations) and revisions (versions) of charts deployed on the cluster. When you run helm commands, your local Helm client sends instructions to tiller in the cluster that in turn make the requested changes.

Installation

While several methods to install Helm exists, the simplest way to install Helm is to run Helm’s installer script in a terminal:

curl https://raw.githubusercontent.com/kubernetes/helm/master/scripts/get | bash

Initialization

After installing helm on your machine, initialize Helm on your Kubernetes cluster:

  1. Set up a ServiceAccount for use by tiller.

    kubectl --namespace kube-system create serviceaccount tiller
    
  2. Give the ServiceAccount full permissions to manage the cluster.

    Note

    While most clusters have RBAC enabled and you need this line, you must skip this step if your Kubernetes cluster does not have RBAC enabled.

    kubectl create clusterrolebinding tiller --clusterrole cluster-admin --serviceaccount=kube-system:tiller
    

    See our RBAC documentation for more information.

  3. Initialize helm and tiller.

    helm init --service-account tiller
    

    This command only needs to run once per Kubernetes cluster, it will create a tiller deployment in the kube-system namespace and setup your local helm client.

    Note

    If you wish to install helm on another computer, you won’t need to setup tiller again but you still need to initialize helm:

    helm init --client-only
    

Verify

You can verify that you have the correct version and that it installed properly by running:

helm version

It should in less then a minute, when tiller on the cluster is ready, be able to provide output like below. Make sure you have at least version 2.11.0 and that the client (helm) and server version (tiller) is matching!

Client: &version.Version{SemVer:"v2.11.0", GitCommit:"2e55dbe1fdb5fdb96b75ff144a339489417b146b", GitTreeState:"clean"}
Server: &version.Version{SemVer:"v2.11.0", GitCommit:"2e55dbe1fdb5fdb96b75ff144a339489417b146b", GitTreeState:"clean"}

Note

If you wish to upgrade the server component of Helm running on the cluster (tiller):

helm init --upgrade --service-account tiller

Secure Helm

Ensure that tiller is secure from access inside the cluster:

kubectl patch deployment tiller-deploy --namespace=kube-system --type=json --patch='[{"op": "add", "path": "/spec/template/spec/containers/0/command", "value": ["/tiller", "--listen=localhost:44134"]}]'

Next Step

Congratulations, Helm is now set up! Let’s continue with Setting up JupyterHub!