Helm

Helm 3: The package manager for Kubernetes. It is the best way to find, share, and use software built for Kubernetes.

helm.sh: code, docs

Quick start

Installation

Start with the installation guide.

On Windows, get the zip file from the Release page and extract the exe file to a folder defined in the PATH environment variable.

Make sure helm is available from the command line: helm version.

Update repository

Then follow the quickstart guide.

Add at least one repository (helm repo ls), for instance helm repo add stable https://charts.helm.sh/stable.

Run helm repo update to update the repository.

You can look at what is available with helm search repo stable.

First try with MySQL

Install the first chart with helm install stable/mysql --generate-name.

The ouput of this command is very interesting:

MySQL can be accessed via port 3306 on the following DNS name from within your cluster: mysql-xxxxxxx.default.svc.cluster.local

To get your root password run: MYSQL_ROOT_PASSWORD=$(kubectl get secret --namespace default mysql-xxxxxxx -o jsonpath="{.data.mysql-root-password}" | base64 --decode; echo)

To connect to your database:

1. Run an Ubuntu pod that you can use as a client: kubectl run -i --tty ubuntu --image=ubuntu:18.04 --restart=Never -- bash -il

2. Install the mysql client: $ apt-get update && apt-get install mysql-client -y

3. Connect using the mysql cli, then provide your password: $ mysql -h mysql-xxxxxxx -p

   To connect to your database directly from outside the K8s cluster: MYSQL_HOST=127.0.0.1, MYSQL_PORT=3306. Execute the following command to route the connection: kubectl port-forward svc/mysql-xxxxxxx 3306 and mysql -h ${MYSQL_HOST} -P${MYSQL_PORT} -u root -p${MYSQL_ROOT_PASSWORD}.

As usual, look at the progress with kubectl get pods ("STATUS" column).

At the end, clean your cluster helm uninstall mysql-xxxxxxx.

Charts

Chart structure

mychart ├── Chart.yaml ├── templates │ ├── deployment.yaml │ └── service.yaml └── values.yaml

CLI reference

Command	Action
helm show chart stable/xxxx	Get a simple idea of the features of chart stable/xxxx (stable/mysql for example)
helm list	See what has been released with Helm
helm help xxx	Get help message on xxx command (install for example)
helm ls	What has been released using Helm
helm uninstall <name>	Uninstall a release