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Install from Helm charts

Helm is a popular package manager for Kubernetes. A Helm chart is a bundle of parameterizable YAML resources for Kubernetes/OpenShift.

Difference with Operators

Helm charts can be defined as Operators (if they are packaged using the operator-sdk), but they are not all Operators.

See the official documentation for Helm on OpenShift.

Install the Helm client​

Install Golang​

Go lang is required to run Helm. Install go 1.14.4 on Linux, you can find instructions for MacOS, Windows and newer versions at https://golang.org/dl

wget https://dl.google.com/go/go1.14.4.linux-amd64.tar.gz

# Extract to /usr/local
tar -C /usr/local -xzf go1.14.4.linux-amd64.tar.gz

# Add Go to path in .profile
echo "export PATH=$PATH:/usr/local/go/bin" >> ~/.profile
# Or in .zshrc if you use ZSH
echo "export PATH=$PATH:/usr/local/go/bin" >> ~/.zshrc

Restart your laptop for the changes to take effects or execute source ~/.profile

Install Helm​

You can also use the official documentation to install Helm on your machine.

Install on Linux​

curl https://raw.githubusercontent.com/helm/helm/master/scripts/get-helm-3 | bash

See Helm documentation for Linux.

Install on MacOS​

brew install helm

See Helm documentation for MacOS.

Install on Windows​

Install using Chocolatey.

choco install kubernetes-helm

See Helm documentation for Windows.

Check Helm installation​

helm version

Install a Helm chart​

Explore published Helm charts at https://hub.helm.sh ⛵

Start a MySQL database with Helm​

Example from the OpenShift 4.3 documentation. See also the official Helm documentation.

  1. Add the repository of official Helm charts to your local Helm client:
helm repo add stable https://kubernetes-charts.storage.googleapis.com/
  1. Update the repository:
helm repo update
  1. Install an example MySQL chart, and start the application named example-mysql:
helm install example-mysql stable/mysql
Password

The instructions to retrieve the admin password and connect to the database will be displayed in the terminal.

Retrieve the database password with this command (N.B.: kubectl can also be used in place of oc):

oc get secret example-mysql -o jsonpath="{.data.mysql-root-password}" | base64 --decode; echo
  1. Verify that the chart has installed successfully:
helm list
  1. Expose the MySQL service as a route:
oc expose service example-mysql
oc get routes

Or port-forward to http://localhost:3306

oc port-forward svc/example-mysql 3306

Uninstall the application​

helm uninstall example-mysql

Set deployment parameters​

You can also define deployment parameters when installing a Helm chart, such as the service account and node selector.

For example, here we make sure the application will run on DSRI CPU nodes and use the anyuid service account:

Add Bitnami repository:

helm repo add bitnami https://charts.bitnami.com/bitnami

Install and start Postgresql:

helm install postgresql-db bitnami/postgresql --set nodeSelector.dsri.unimaas.nl/cpu=true --set serviceAccount.name=anyuid