Flux CD vs Helm: What are the differences?

Flux CD and Helm are two popular tools used in the Kubernetes ecosystem. Let's explore the key differences between them.

1. Deployment Strategy: Flux CD follows the GitOps approach, where the desired state of the cluster is defined in a Git repository, and Flux CD ensures that the actual state of the cluster matches the desired state. On the other hand, Helm is a package manager for Kubernetes that provides a templating engine for simplifying the deployment of complex applications.

2. Application Packaging: Flux CD focuses on continuous delivery by synchronizing changes from a Git repository to the cluster. It treats the Kubernetes manifests as the source of truth for application deployments. In contrast, Helm packages applications as reusable charts, providing a higher-level abstraction that includes dependencies, configuration, and metadata.

3. Granularity: Flux CD operates at the infrastructure level, managing the deployment of entire applications or services. It is primarily concerned with the structure and configuration necessary to run the application. Helm, on the other hand, allows fine-grained control over the deployment process. It enables users to define and manage specific components, such as Pods, Services, and ConfigMaps, within an application.

4. Versioning and Rollbacks: Flux CD tracks changes made to the Git repository, allowing rollbacks to previous versions if required. It ensures that only the desired versions are deployed to the cluster. With Helm, versioning and rollbacks are managed at the chart level. Helm maintains a release history, enabling easy rollback to previous chart versions, even if the chart configurations have changed.

5. Helm Repository: Helm provides a centralized repository (Helm Hub) where users can discover and share Helm charts. This makes it easier to find and use existing charts for different applications or services. Flux CD, on the other hand, relies on regular Git repositories to store and manage the Kubernetes manifests. Users need to maintain their own Git repositories or use a central Git repository management system.

6. Templating and Configuration: Helm offers a powerful templating engine that allows users to define dynamic configurations using variables, loops, and conditionals. This makes it easier to create reusable and customizable application configurations. Flux CD, being focused on synchronization, does not provide built-in templating capabilities. Any configuration templating needs to be handled externally before pushing the manifests to the Git repository.

In summary, Flux CD follows the GitOps approach, focusing on continuous delivery and infrastructure-level management of applications, while Helm is a package manager for Kubernetes that allows fine-grained control over deployments and provides a centralized repository for sharing charts.