A simple Helm demo

Setup

We are going to deploy three instances of the awesome-app. One will be prd, one tst and one dev. Thus, we first want three namespaces.

kubectl create ns awesome-helm
kubectl create ns awesome-helm-tst
kubectl create ns awesome-helm-dev

Deploy from a local chart

Clone this repo.

git clone [email protected]:bespinian/helm-demo.git
cd helm-demo
ls -l

Note the typical layout of a Helm chart. The file Chart.yaml contains the chart metadata including a conditional dependency on bitnami/postgresql. The templates directory contains templates for the resources which are deployed. The charts directory contains Helm charts on which this chart is depending. In this case, this is bitnami/postgresql. Furthermore, there are three values files:

• values.yaml: the default values, used in our case for production.
• values-tst.yaml: the values used for the test environment. Note the override of the replicaCount.
• values-dev.yaml: the values used for the development environment. Note the use of the local Postgresql DB in this case.

Deploy prd

We issue the following command to deploy the prd instance:

helm install prd . --namespace awesome-helm

Note that we do not need to specify any values file as this is the default setup. We see that the app is deployed with 3 replicas and no database running inside the cluster.

Deploy tst

We issue the following command to deploy the tst instance:

helm install tst . -f values-tst.yaml --namespace awesome-helm-tst

Note that we tell Helm to use values-tst.yaml instead of the default.

Deploy dev

We issue the following command to deploy the dev instance:

helm install dev . -f values-dev.yaml --namespace awesome-helm-dev

Note that we tell Helm to use values-dev.yaml instead of the default. We see that in this case, a local Postgresql instance is deployed to the same namespace.

Uninstalling charts

We can uninstall the dev, tst and prd instances with the following commands:

helm uninstall dev --namespace awesome-helm-dev
helm uninstall tst --namespace awesome-helm-tst
helm uninstall prd --namespace awesome-helm

Deploy from a remote Helm repo

Add the repo

Take a look at https://bespinian.github.io/charts. There you will find the typical layout of a Helm repo consisting of an index.yaml file along with the packaged Helm charts which are being served from this particular repo.

We can add the repo to Helm with the following command:

helm repo add bespinian https://bespinian.github.io/charts

Install dev from the remote repo

Now that we have added the remote repo under the name bespinian, we can install the chart directly from it, using the values file for the dev environment.

helm install dev bespinian/helm-demo -f values-dev.yaml --namespace awesome-helm-dev

Clean up

Finally we remove the dev instance again:

helm uninstall dev --namespace awesome-helm-dev