Working with Helm

Now that Helm is installed, let's dive into the core functionalities of working with Helm. Whether you're installing a new application, upgrading an existing deployment, or managing multiple releases, Helm makes Kubernetes operations much simpler.

1. Installing a Chart

The primary function of Helm is to install applications using Charts. A Chart is a package of pre-configured Kubernetes resources, and you can install it into your cluster using the helm install command. Here’s an example of installing Nginx from the Bitnami repository:

helm install my-nginx bitnami/nginx

• my-nginx: This is the name of the release. You can choose any name for your release.
• bitnami/nginx: This specifies the repository and chart you want to install.

After running the command, Helm will deploy Nginx and output details about the resources created in your cluster.

2. Listing Installed Releases

To see which Helm-managed applications (or Releases) are installed in your cluster, use the helm list command:

helm list

This will display a list of all releases, including their names, statuses, and the Chart version they are using.

3. Viewing a Release

If you want to inspect a specific release for details like the status, associated resources, or last revision, you can use the helm status command:

helm status my-nginx

This command shows detailed information about the release, including the current state of the application, which can be helpful for debugging.

4. Upgrading a Release

One of the key features of Helm is the ability to upgrade a release with new configurations or Chart versions without redeploying everything from scratch. Let’s say you want to change the service type of Nginx from the default to NodePort. You can do this by upgrading the release:

helm upgrade my-nginx bitnami/nginx --set service.type=NodePort

In this command:

• helm upgrade tells Helm to update an existing release.
• my-nginx is the release name.
• bitnami/nginx is the chart you are upgrading.
• --set service.type=NodePort overrides the default service type.

Helm will make the changes in your cluster without interrupting the application unless necessary.

5. Rolling Back a Release

Sometimes, things don't go as planned after an upgrade. Helm makes it easy to revert back to a previous version with the helm rollback command:

helm rollback my-nginx 1

The number 1 refers to the revision number you want to roll back to. Helm keeps track of all your releases' revisions, so you can easily roll back to a previous version if something goes wrong.

6. Uninstalling a Release

If you no longer need a particular release, Helm allows you to uninstall it, which will clean up all the associated Kubernetes resources:

helm uninstall my-nginx

This command will delete all Kubernetes resources associated with the my-nginx release, but the release history is retained by Helm, allowing you to reinstall it later if needed.

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These commands form the foundation of working with Helm, helping you install, manage, and update applications in your Kubernetes cluster efficiently. In the next section, we’ll explore how to customize Helm Charts to better fit your specific application needs.