Chapter 3. Helm CLI
3.1. Getting started with Helm 3 on OpenShift Container Platform
Helm 3 for OpenShift Container Platform is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.
For more information about the support scope of Red Hat Technology Preview features, see https://access.redhat.com/support/offerings/techpreview/.
3.1.1. Understanding Helm
Helm is a command-line interface (CLI) tool that simplifies deployment of applications and services to OpenShift Container Platform clusters. Helm uses a packaging format called charts. A Helm chart is a collection of files that describes OpenShift Container Platform resources.
3.1.1.1. Key features
Helm provides the ability to:
- Search through a large collection of charts stored in the chart repository.
- Modify existing charts.
- Create your own charts with OpenShift Container Platform or Kubernetes resources.
- Package and share your applications as charts.
3.1.2. Installing Helm
Prerequisites
- You have installed Go, version 1.13 or higher.
3.1.2.1. On Linux
Download the Helm binary and add it to your path:
# curl -L https://mirror.openshift.com/pub/openshift-v4/clients/helm/latest/helm-linux-amd64 -o /usr/local/bin/helm
Make the binary file executable:
# chmod +x /usr/local/bin/helm
Check the installed version:
$ helm version version.BuildInfo{Version:"v3.0", GitCommit:"b31719aab7963acf4887a1c1e6d5e53378e34d93", GitTreeState:"clean", GoVersion:"go1.13.4"}
3.1.2.2. On Windows 7/8
-
Download the latest
.exe
file and put in a directory of your preference. - Right click Start and click Control Panel.
- Select System and Security and then click System.
- From the menu on the left, select Advanced systems settings and click Environment Variables at the bottom.
- Select Path from the Variable section and click Edit.
-
Click New and type the path to the folder with the
.exe
file into the field or click Browse and select the directory, and click OK.
3.1.2.3. On Windows 10
-
Download the latest
.exe
file and put in a directory of your preference. -
Click Search and type
env
orenvironment
. - Select Edit environment variables for your account.
- Select Path from the Variable section and click Edit.
- Click New and type the path to the directory with the exe file into the field or click Browse and select the directory, and click OK.
3.1.2.4. On MacOS
Download the Helm binary and add it to your path:
# curl -L https://mirror.openshift.com/pub/openshift-v4/clients/helm/latest/helm-darwin-amd64 -o /usr/local/bin/helm
Make the binary file executable:
# chmod +x /usr/local/bin/helm
Check the installed version:
$ helm version version.BuildInfo{Version:"v3.0", GitCommit:"b31719aab7963acf4887a1c1e6d5e53378e34d93", GitTreeState:"clean", GoVersion:"go1.13.4"}
3.1.3. Installing a Helm chart on an OpenShift Container Platform cluster
Prerequisites
- You have a running OpenShift Container Platform cluster and you have logged into it.
- You have installed Helm.
Procedure
Create a new project:
$ oc new-project mysql
Add a repository of Helm charts to your local Helm client:
$ helm repo add stable https://kubernetes-charts.storage.googleapis.com/ "stable" has been added to your repositories
Update the repository:
$ helm repo update
Install an example MySQL chart:
$ helm install example-mysql stable/mysql
Verify that the chart has installed successfully:
$ helm list NAME NAMESPACE REVISION UPDATED STATUS CHART APP VERSION example-mysql mysql 1 2019-12-05 15:06:51.379134163 -0500 EST deployed mysql-1.5.0 5.7.27
3.1.4. Creating a custom Helm chart on OpenShift Container Platform
Procedure
Create a new project:
$ oc new-project nodejs-ex-k
Download an example Node.js chart that contains OpenShift Container Platform objects:
$ git clone https://github.com/redhat-developer/redhat-helm-charts
Go to the directory with the sample chart:
$ cd redhat-helm-charts/alpha/nodejs-ex-k/
Edit the
Chart.yaml
file and add a description of your chart:apiVersion: v2 1 name: nodejs-ex-k 2 description: A Helm chart for OpenShift 3 icon: https://static.redhat.com/libs/redhat/brand-assets/latest/corp/logo.svg 4
Verify that the chart is formatted properly:
$ helm lint [INFO] Chart.yaml: icon is recommended 1 chart(s) linted, 0 chart(s) failed
Install the chart:
$ cd .. $ helm install nodejs-chart nodejs-ex-k
Verify that the chart has installed successfully:
$ helm list NAME NAMESPACE REVISION UPDATED STATUS CHART APP VERSION nodejs-chart nodejs-ex-k 1 2019-12-05 15:06:51.379134163 -0500 EST deployed nodejs-0.1.0 1.16.0