Helm in Kubernetes: The Evolution from Tiller to Modern Security

Helm is a powerful package manager for Kubernetes. It enables the management of Kubernetes applications through the use of package charts. However, the transition from Tiller, a component that was once central to Helm operations, brought about significant changes in the security and management of Helm. In this article, we will explore the evolution of Helm, focusing on how it has changed since the deprecation of Tiller in favor of a client-only approach.

Introduction to Helm and Tiller

Helm is used to install and manage Kubernetes applications using package charts. These charts are essentially sets of configuration files that define a complete package of software for a given application. Before the release of Helm 3, Tiller was a component that ran inside the Kubernetes cluster as a server that interacted with the Kubernetes API server to manage and facilitate the installation of these charts.

The Risks and Challenges with Tiller

Tiller presented a significant security risk. Since it operated as a privileged service within the cluster, any security vulnerabilities in Tiller could potentially lead to unauthorized access to the entire cluster. Additionally, Tiller required ADDONS to be enabled, which further complicated the cluster's security posture.

Deprecation of Tiller in Helm 3

Starting from Helm 3, Tiller was officially deprecated. Helm 3, introduced in 2019, marked a shift in the way Helm operates, making it a client-only application. This means that Helm 3 no longer includes a server component (Tiller) that interacts with the Kubernetes API server. Instead, Helm 3 leverages Kubectx, which is the client application that runs on the user's machine. This change has several benefits:

Improved Security: The removal of Tiller as a privileged service within the cluster significantly reduces the risk of unauthorized access. Users now need to manage access permissions at the client level. Simplified Management: As Helm operates solely as a client application, it simplifies the management and configuration process for users. Enhanced Flexibility: Since Helm 3 does not include a server component, it offers greater flexibility in deployment and management, allowing users to bypass Kubernetes cluster limitations.

Advantages of the Client-Only Approach

With the shift to a client-only approach, Helm 3 offers several advantages, including:

Improved Security: By minimizing the number of privileged services in the cluster, the overall security posture is strengthened. Ease of Use: Users find it easier to configure and manage Helm operations, especially for those new to Kubernetes. Flexibility: The client-only approach allows for more flexible deployment and management strategies, accommodating different use cases and environments.

Conclusion

The evolution of Helm from incorporating a server component like Tiller to becoming a client-only application marks a significant step forward in the management and security of Kubernetes applications. With the maintenance of security and ease of use, Helm in its current form provides a robust and reliable solution for deploying and managing applications within a Kubernetes cluster.

Keywords: Helm, Kubernetes, Tiller