Helm: A Comprehensive Guide to Managing Kubernetes Packages (with examples)

Helm is a package manager for Kubernetes that simplifies the deployment and management of applications on a Kubernetes cluster. It allows users to easily package, distribute, and install applications and services in a consistent manner. In this article, we will explore various use cases of the Helm command with detailed examples.

Use Case 1: Creating a Helm Chart

To create a Helm chart, you can use the following command:

helm create chart_name

• Motivation: Creating a Helm chart is the first step in packaging applications for deployment on a Kubernetes cluster. Helm charts encapsulate all the necessary Kubernetes resources, such as deployments, services, and config maps, into a single package.
• Explanation: The helm create command generates a directory structure with pre-defined templates for various Kubernetes resources. It also creates a values.yaml file for configuring the chart’s values.
• Example Output: Running helm create mychart will create a directory named mychart with the necessary files and templates for a Helm chart.

Use Case 2: Adding a New Helm Repository

To add a new Helm repository, you can use the following command:

helm repo add repository_name repository_url

• Motivation: Helm repositories provide a centralized location for hosting Helm charts. By adding a new repository, you can access and install Helm charts available in that repository.
• Explanation: The helm repo add command adds a new repository to the list of available repositories in Helm. It requires two arguments: repository_name is a name given to the repository for future reference, and repository_url is the URL of the repository.
• Example Output: Running helm repo add stable https://charts.helm.sh/stable will add the Helm stable repository with the given URL to the list of available repositories.

Use Case 3: Listing Helm Repositories

To list all the Helm repositories, you can use the following command:

helm repo list

• Motivation: Listing the Helm repositories helps you visualize the available repositories and their associated URLs. This information can be useful when searching for Helm charts to install.
• Explanation: The helm repo list command provides a tabular view of all the repositories added to Helm. It displays the repository name, URL, and the latest version of the repository’s index file.
• Example Output:

  NAME  	URL                             
  stable	https://charts.helm.sh/stable    
  

Use Case 4: Updating Helm Repositories

To update the Helm repositories and fetch the latest charts, you can use the following command:

helm repo update

• Motivation: Updating Helm repositories ensures that you have access to the latest versions of the charts available in those repositories. This command is particularly useful when you want to install updated or new Helm charts.
• Explanation: The helm repo update command fetches the latest version of the repository’s index file from all the added repositories. It compares the local index file with the remote one and updates it if necessary.
• Example Output: Running helm repo update will display the status of each repository being updated, such as stable ... OK.

Use Case 5: Deleting a Helm Repository

To delete a Helm repository, you can use the following command:

helm repo remove repository_name

• Motivation: Removing a Helm repository is useful when you no longer need to access the Helm charts available in that repository. It helps declutter the list of available repositories and reduces the chances of installing outdated or deprecated charts.
• Explanation: The helm repo remove command removes a repository from the list of available repositories. It requires the repository_name as an argument, which is the name given to the repository during the addition.
• Example Output: Running helm repo remove stable will remove the Helm stable repository from the list of available repositories.

Use Case 6: Installing a Helm Chart

To install a Helm chart from a specific repository, you can use the following command:

helm install name repository_name/chart_name

• Motivation: Installing a Helm chart is the primary purpose of using Helm. It allows you to deploy pre-packaged applications on a Kubernetes cluster with ease. By specifying the chart name and the repository, Helm fetches the chart and installs it on the cluster.
• Explanation: The helm install command deploys a Helm chart on a Kubernetes cluster. It requires two arguments: name is the name given to the release, and repository_name/chart_name specifies the chart to be installed from a specific repository.
• Example Output: Running helm install myapp stable/nginx-ingress will deploy the Nginx Ingress Controller chart from the stable repository with the release name myapp.

Use Case 7: Downloading a Helm Chart as a Tar Archive

To download a Helm chart as a tar archive, you can use the following command:

helm get chart_release_name

• Motivation: Downloading a Helm chart as a tar archive can be helpful when you want to inspect the contents of a released chart or share it with others who don’t have access to the repository from where it was originally installed.
• Explanation: The helm get command retrieves information about a released Helm chart. By specifying the chart_release_name, which is the name of the deployed release, Helm fetches the chart and saves it as a tar archive in the current directory.
• Example Output: Running helm get myapp will save the Helm chart associated with the release myapp as a tar archive named myapp-<version>.tgz.

Use Case 8: Updating Helm Dependencies

To update the dependencies of a Helm chart, you can use the following command:

helm dependency update

• Motivation: Helm allows you to define dependencies between different charts. When a chart depends on other charts, updating the dependencies ensures that the latest versions of those charts are used during installation or upgrade.
• Explanation: The helm dependency update command updates the dependencies of the current Helm chart. It reads the requirements.yaml file, resolves the dependencies, and fetches the latest versions of those charts.
• Example Output: Running helm dependency update will retrieve the latest versions of the dependencies specified in the requirements.yaml file and update the charts directory accordingly.

By understanding and utilizing the various use cases of the Helm command, you can effectively manage Kubernetes packages using Helm. Whether it is creating a new Helm chart, installing a pre-packaged application, or updating dependencies, Helm provides a comprehensive solution for simplifying application deployment on Kubernetes clusters.