Introduction

Helm is a powerful package manager for Kubernetes, allowing users to deploy applications easily. When using Helm, every installation must have a unique name within a namespace. By default, if no namespace is specified, Kubernetes assigns deployments to the default namespace.

In this tutorial, we will explore how to install a Helm chart into a specific namespace, avoiding name conflicts when deploying the same chart multiple times.

Understanding Helm Installation and Namespace Constraints

When you run the helm install command, you provide an installation name along with the Helm chart name. However, Kubernetes enforces that each installation name must be unique within a given namespace. If you try to execute the same helm install command again without changing the namespace, you will encounter the following error:

Error: cannot reuse a name that is still in use

To resolve this, you have two options:

1. Delete the existing installation (covered in a later section).
2. Install the chart in a different namespace.

Using a different namespace is often the better choice, especially when deploying multiple instances of the same application for different teams or environments.

Creating a New Namespace

To create a new namespace in Kubernetes, use the following command:

kubectl create ns team-two

This command creates a namespace called team-two. Now, instead of using the default namespace, we can deploy our Helm chart into team-two.

Installing Helm Chart into a Specific Namespace

To install a Helm chart into the newly created namespace, modify the helm install command to include the namespace parameter. You can specify the namespace using either of these options:

• -n (short for --namespace)
• --namespace

Example Command

helm install -n team-two mydb <chart-name>

or

helm install --namespace team-two mydb <chart-name>

Expected Outcome

If executed correctly, the installation should proceed without errors. You will see output similar to the previous installation, but this time, the deployment is happening in the team-two namespace instead of the default namespace.

Verifying the Installation

To check that the Helm release has been installed in the correct namespace, use the following command:

helm list -n team-two

This will display a list of Helm releases in the team-two namespace, confirming that the deployment was successful.

Key Takeaways

• Every Helm installation name must be unique within a namespace.
• If you attempt to install the same Helm release in the same namespace, Kubernetes will return an error.
• To resolve conflicts, you can either delete the existing installation or deploy to a different namespace.
• Use kubectl create ns <namespace-name> to create a new namespace.
• Specify the namespace during installation using -n or --namespace with the helm install command.

By following these best practices, you can efficiently manage multiple Helm deployments across different namespaces in your Kubernetes cluster.