Helm vs Jsonnet: What are the differences?

Introduction

In the world of cloud-native application development and infrastructure management, there are various tools available to ease the deployment process. Two such popular tools are Helm and Jsonnet. While both aim to simplify application deployment and management, they differ in their approach and functionality. This article will outline the key differences between Helm and Jsonnet.

1. Helm: Simplified Package Management for Kubernetes: Helm is a package manager for Kubernetes applications, providing a way to define, install, and manage applications and their dependencies on a Kubernetes cluster. It uses charts, which are packages of pre-configured Kubernetes resources, to simplify the deployment process. Helm allows for the customization of charts through the use of values files, enabling the configuration of application parameters. Helm also offers functionalities like release management, helm repositories, and chart versioning, making it a comprehensive tool for managing Kubernetes applications.

2. Jsonnet: Flexible and Programmable Configuration: Jsonnet is a data templating language that allows for the flexible and programmable generation of JSON data. With Jsonnet, complex JSON structures and configurations can be defined and generated dynamically, reducing redundancy and enhancing maintainability. Jsonnet introduces features like code reuse through functions, the ability to define variables and objects, and imports, making configuration generation more modular and reusable. Unlike Helm, Jsonnet does not focus specifically on Kubernetes application and package management but can be used for overall configuration generation in various contexts.

3. Helm Charts vs. Jsonnet Configurations: Helm uses charts as a way to package and distribute Kubernetes applications. Charts are a bundle of Kubernetes resources, packaged together with customizable configuration values. Helm charts are written in YAML, making it easy to define and manage Kubernetes resources. Jsonnet, on the other hand, focuses on the generation of JSON data structures and configurations. It provides a more flexible and programmable approach to configuration management compared to Helm. With Jsonnet, the entire JSON structure can be generated dynamically, enabling more complex configuration setups.

4. Chart Templating vs. Jsonnet Templating: Helm utilizes Go-templates for chart templating, allowing for the dynamic generation of Kubernetes resource configurations using a syntax similar to the Go programming language. Templating allows for the customization of values within the charts, making it easier to create reusable configurations. Jsonnet, on the other hand, provides native templating capabilities as part of the language itself. While Go-templates focus specifically on Kubernetes resource configurations, Jsonnet allows for the creation of complex JSON structures with programmable logic and modular code reuse.

5. Helm Extensions vs. Jsonnet Libraries: Helm offers extensions or plugins that provide additional functionalities beyond basic chart templating. These extensions, known as hooks, allow for lifecycle management, running additional scripts or actions before, during, or after certain events in the application lifecycle. Jsonnet does not have a specific extension or plugin system; however, it provides libraries that can be imported and reused in different Jsonnet configurations. These libraries can contain helper functions, common object structures, or any other reusable code, enhancing the modularity and maintainability of Jsonnet configurations.

6. Community and Ecosystem: Helm has a well-established community and ecosystem, with a vast number of pre-built charts available for various applications and services. The Helm community actively maintains the helm/charts repository, which hosts a wide range of charts submitted by the community. In addition, Helm has an ecosystem of tools and plugins that extend its functionality. Jsonnet also has an active community, but its ecosystem is not as extensive as Helm's. While Jsonnet can be used in various contexts, it might require more manual configuration and customization compared to the comprehensive ecosystem provided by Helm.

In summary, Helm is a package manager specifically designed for Kubernetes applications, simplifying the deployment and management process through pre-configured charts. Jsonnet, on the other hand, is a flexible and programmable language for generating JSON configurations, which can be used in various contexts beyond Kubernetes application management. Whilst they share some commonalities, Helm focuses on package management, chart templating, and an extensive community, while Jsonnet focuses on configuration generation, native templating, and code reuse.