Install Helm

Installing software into an existing Kubernetes cluster is trivial with Helm. You can think of Helm as a package manager for Kubernetes. The packages Helm installs are called Charts and we'll be using the Grey Matter Helm Chart in this tutorial. But before we can do that, we first need to install Helm locally. The following command downloads the Helm binary and places it in /usr/local/bin/helm. Since our ${PATH} environment variable includes /usr/local/bin we can invoke Helm by simply typing helm for the rest of this tutorial.

curl -sSL https://get.helm.sh/helm-v2.14.1-linux-amd64.tar.gz | tar -xz --strip-components=1 --directory=/usr/local/bin

Install Tiller

With Helm installed locally, we need to install the server side component, Tiller. In reality, it is Tiller that deploys the Kubernetes resources on behalf of Helm. Fortunately, Helm is perfectly capable of installing Tiller for us with the following command.

helm init --tiller-namespace kube-system --service-account default

The above command installs Tiller within the kube-system Kubernetes namespace using the default service account. For the purposes of this tutorial, this will suffice but before using Tiller in a production environment you should be aware of the security implications and some best practices mentioned.

Bind the Tiller Service Account to the Cluster-Admin Role

We need to tell our cluster that Tiller is a service account that requires administrative permissions to deploy Grey Matter. We can do this by explicitly naming Tiller as a service account and binding it to the relevant cluster role.

kubectl create serviceaccount tiller --namespace kube-system

Next we need to define how Tiller will be bound to this role. We'll do this by creating a tiller-clusterrolebinding.yaml file with the following contents:

vi /root/tiller-clusterrolebinding.yaml

or

nano /root/tiller-clusterrolebinding.yaml

Paste the following snippet into this file:

kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: tiller-clusterrolebinding
subjects:
- kind: ServiceAccount
  name: tiller
  namespace: kube-system
roleRef:
  kind: ClusterRole
  name: cluster-admin
  apiGroup: ""

The last thing we need to do to configure our cluster for installation is deploy the cluster role binding file. kubectl create -f /root/tiller-clusterrolebinding.yaml

Refresh our Tiller initialization to ensure that these changes take effect: helm init --service-account tiller --upgrade

For testing purposes, clone the repo from GitHub

git clone --single-branch --branch katacoda https://github.com/DecipherNow/helm-charts

Define a custom.yaml file and Install Grey Matter

The custom.yaml file informs helm how we want to install Greymatter. This file holds credentials, configurable overrides for the sub-charts' values.yaml files, and some certifications.

Edit this file to fill in the relevant credentials vi custom.yaml or nano custom.yaml

helm dep up helm-charts/greymatter

Now we can install Grey Matter into our cluster.

Select the installation command associated with your custom.yaml file

helm install --name gm-my-cluster --tiller-namespace kube-system --debug -f /root/custom.yaml helm-charts/greymatter