Kustomize vs Skaffold: What are the differences?

Introduction

Kustomize and Skaffold are two popular tools used in the Kubernetes ecosystem for managing application deployments. While both tools serve a similar purpose, there are key differences that set them apart. This article will highlight these differences between Kustomize and Skaffold and provide a concise comparison.

1. Kustomize provides declarative configuration management: Kustomize allows users to define their desired deployment configuration in a declarative manner using YAML files. It provides a way to customize Kubernetes resource manifests without modifying the original files directly. With Kustomize, users can easily reuse and customize configurations across different environments.

2. Skaffold offers a streamlined development workflow: Skaffold simplifies the local development process by providing a seamless workflow for building, pushing, and deploying applications to a Kubernetes cluster. It supports various build tools, such as Docker and Jib, and includes features like hot reloading for faster iteration during development. Skaffold enables developers to focus on writing code rather than managing the deployment process.

3. Kustomize is a built-in tool in Kubernetes: Kustomize is integrated into the Kubernetes command-line interface (kubectl) as a separate subcommand. This means that Kustomize is readily available without the need for any additional installation or configuration. Users can leverage Kustomize's functionality directly from their Kubernetes environment.

4. Skaffold supports multiple cluster targets: Skaffold provides the ability to deploy applications to different Kubernetes clusters or even different cloud providers. This flexibility allows developers to easily switch between development, staging, and production environments with minimal effort. Skaffold abstracts away the complexities of managing clusters, making it easier to work in a multi-cluster environment.

5. Kustomize focuses on customization and composition: Kustomize is designed to provide a way to compose and customize Kubernetes resource manifests. It allows users to merge multiple manifests together, patch existing resource definitions, and apply overlays for environment-specific configurations. Kustomize excels at managing complex configurations and making them more maintainable.

6. Skaffold supports a wider range of development tools: Skaffold integrates with a variety of development tools, making it compatible with different workflows and preferences. It works well with IDEs like Visual Studio Code and IntelliJ IDEA, build tools like Maven and Gradle, and even testing frameworks like JUnit. Skaffold offers a flexible choice of tools to accommodate developers' needs.

In summary, Kustomize focuses on declarative configuration management and customization of Kubernetes resource manifests, while Skaffold provides a streamlined development workflow and supports various development tools. Both tools have their strengths and can be used together to enhance the Kubernetes application deployment process.