What Is a Helm Chart? The Most Effective Way to Manage Kubernetes Applications

Are you overwhelmed by having to manage dozens of separate YAML configuration files every time you deploy an application to Kubernetes? That’s when you need Helm Chart – a solution often described as the key to escaping configuration hell.

So, what exactly is a Helm Chart, and how does this tool help you package, share, and deploy complex applications with just a single command? Let’s explore it with Viettel IDC below.

What Is Helm?

Before diving deeper into what a Helm Chart is, we first need to understand the tool that operates it – Helm.

Helm is a Package Manager for Kubernetes. Think of Helm as being similar to apt on Ubuntu or yum on CentOS, but instead of installing software on a Linux operating system, Helm helps you install and manage applications on the Kubernetes platform.

The primary role of Helm is to simplify the complexity of operating Kubernetes. It allows developers and system administrators to:

- Package: Bundle separate configuration files into a single unit for easier sharing and distribution.

- Manage Dependencies: Automatically handle the libraries or supporting services required by an application.

- Deploy Consistently: Quickly replicate and configure identical Clusters, streamlining deployment across different environments, from Development to Production.

What Is a Helm Chart?

A Helm Chart is the packaging format used by Helm. Essentially, a Helm Chart is a collection of structured files containing all the information required to define, install, and manage a Kubernetes application.

Each Chart acts as a specific set of instructions for a single application. Helm uses these instructions to generate deployable resources. With this model, Helm can manage the entire application lifecycle, including installation, upgrades, and removal.

One of the biggest strengths of Helm Charts is their flexibility across multiple environments. They allow operators to install the same application across different environments (such as Staging or Production) using a single Chart.

For example, you can use the same Chart for both Test and Production environments. However, through the values.yaml configuration file, you can configure the Test environment to use fewer resources while allocating more powerful resources to the Production environment. Everything can be managed neatly within the same Helm Chart package.

Structure of a Helm Chart

To fully understand what a Helm Chart is, you need to understand its directory structure. A Helm Chart is not a single file but a collection of files organized according to a strict standard.

1. Root Directory

This is the top-level directory containing all files related to a specific Chart. It serves as the location for organizing and storing configurations and template files.

Within the root directory, you will find:

- Chart.yaml: Contains identification and metadata information.

- charts/: Contains dependent Charts that the application requires to run.

- templates/: Contains definitions of Kubernetes resources.

2. Templates Directory

The templates/ directory is the heart of a Helm Chart. This is where Kubernetes resources such as Deployments, Services, and Ingresses are defined through template files.

These files have a .yaml extension and contain the Go template language. Helm processes these templates and combines them with input values from the values.yaml file to generate complete Kubernetes Manifests tailored to each environment.

This structure allows you to reuse the same code for multiple deployments. The Templates directory serves as the customization layer, directly controlling how resources are provisioned and managed.

3. Values.yaml File

The values.yaml file contains the default configuration values for a Chart. This is the file users interact with most frequently. It contains parametric values that are inserted into files within the templates/ directory.

Users can customize a deployment by overriding the values in this file when running the installation command. This gives the Chart broad adaptability without requiring changes to the template code.

In addition, data in values.yaml is organized in a hierarchical structure, allowing Helm to implement conditional logic (if/else) and loops within templates, providing detailed control over resource configurations.

4. Chart.yaml File

The Chart.yaml file serves as the identity card of a Helm Chart, providing important metadata, including the Chart name, version number, detailed description, and more.

Helm uses this file to determine the Chart's identity and version information – critical factors when installing, upgrading, or managing package dependencies. For example, it helps determine whether a Chart version is a stable release or a development version, supporting effective version control.

Why Should You Use Helm Charts in Kubernetes?

1. Simplify the Deployment Process

Helm Charts provide a streamlined approach by packaging all the necessary resources and configurations into a single unit. This abstraction allows developers to deploy applications quickly without having to deeply understand every complex resource object in Kubernetes.

Moreover, Helm simplifies the application management lifecycle, from installation and updates to managing lifecycle hooks. Using Helm significantly reduces the complexity and human errors that commonly occur when configuring Kubernetes manually.

2. Reusability and Sharing

One of Helm’s greatest advantages is its ability to facilitate sharing. Helm Charts can be shared internally within an organization or with the broader Kubernetes community, creating a standardized approach to application installation.

This helps accelerate deployment processes and ensures consistency across environments. By leveraging standardized Charts from the community, technical teams can focus on application customization rather than spending time setting up basic configurations from scratch.

3. Flexibility with Templates and Parameters

Helm’s templating mechanism integrates closely with Kubernetes, allowing users to parameterize their deployments. Through the values.yaml file and templates, Helm can dynamically generate Kubernetes resource files tailored to specific environments.

This approach promotes the DRY (Don’t Repeat Yourself) principle, helping reduce errors and duplication across manifest files. You can easily manage configuration differences between Development environments (with lower resource requirements) and Production environments (with higher resource requirements) without maintaining multiple versions of configuration files.

4. Version Management and Safe Rollbacks

Helm provides explicit version control for each Chart. This is a critical feature for maintaining stability when updating applications.

Each Chart version corresponds to a specific configuration set. If an update encounters problems, you can use Helm’s Rollback feature to immediately return to the previously stable version. This feature minimizes risks, ensures service reliability, and strongly supports Continuous Delivery strategies in DevOps.

How to Use Helm Charts in Kubernetes

1. Prepare the Environment

Before you start using Helm Charts, make sure you have:

- A Kubernetes Cluster: You need access to a functioning Kubernetes Cluster, which can be Minikube on a local machine or a Cloud-based Cluster such as Viettel Open Kubernetes Service.

- A Compatible Version: For optimal stability, it is recommended to use the latest stable version of Kubernetes.

- Kubectl: Make sure kubectl is installed on your computer and configured to connect to the Cluster.

2. Install the Helm Client

The first step is to download and install the Helm command-line tool (Helm CLI) on your local machine. You can download the binary from Helm’s GitHub Releases page or use package managers:

- On macOS: brew install helm

- On Windows (using Chocolatey): choco install kubernetes-helm

Once installed, Helm acts as a bridge that allows you to interact with Helm Charts and Kubernetes Clusters.

3. Initialize and Add a Chart Repository

Similar to adding a package source for apt or yum on Linux, you need to add Helm Repositories to download applications.

For example, to add the popular Bitnami repository, use the following command:

After adding the repository, you can search for available Charts using:

Result: The system will display a list of available Charts (such as WordPress, Nginx, MySQL, etc.), along with their versions and detailed descriptions.

4. Install an Application Using a Helm Chart

This is the most powerful step. Instead of writing dozens of YAML files, you only need a single command to deploy an application.

For example, to install Prometheus, a popular Kubernetes monitoring tool, the process is as follows:

Step 1: Update Repository Data

Step 2: Add the Prometheus Community Repository

Step 3: Install the Chart

Here, my-prometheus is the name you assign to this Release.

Result: Immediately after running the command, Helm automatically deploys all Prometheus components (Server, Alertmanager, Node Exporter, etc.) to your Cluster. The screen will display the DEPLOYED status along with instructions for accessing the application.

Conclusion

In summary, Helm Charts are not merely a packaging tool; they are a powerful assistant that helps DevOps Engineers and developers tame the complexity of Kubernetes. From standardizing processes and saving deployment time to providing flexible version management and rollback capabilities, Helm has become an indispensable gold standard in modern CI/CD workflows.

Mastering Helm Charts enables businesses to transition from manual and error-prone infrastructure management to a more automated, consistent, and professional process.

However, to fully leverage the power of Helm, you need a robust, stable, and internationally standardized Kubernetes infrastructure platform. Combine the convenience of Helm with the power of Viettel Open Kubernetes Service (vOKS). We provide a fully managed Kubernetes environment that allows you to deploy even the most complex Helm Charts within minutes, without having to worry about the underlying infrastructure operations.

Discover Vietnam’s leading Kubernetes solution at: https://viettelidc.com.vn/en/viettel-kubernetes-service