GitOps w/ Flux

What is GitOps?

• GitOps is a set of practices built around using Git as your system’s source of truth.
• Storing the system’s desired state in version control is crucial for implementing GitOps.
• GitOps and Kubernetes generally go together. Your system consists of Kubernetes-based infrastructure and the applications running on top of it.
• Defining your apps and k8s infrastructure is done declaratively using k8s manifest files.
• You can synchronize the configuration stored in Git with the active cluster configuration using controllers.

Benefits of GitOps

• Traceability - Knowing “who” did what.
• Transparency - Knowing “what” is there.
• Knowledge Sharing via Git - Allows individuals to easily understand your system using code rather than digging into the system itself. (Consider using kubectl commands instead of reading manifest files from one location.)
• Deployments are straightforward - Commit to a branch on Git.
• Tooling has matured to:
  • Performing state management for your cluster + resources.
  • Performing the deployment of resources to the cluster & cloud infrastructure.

GitOps Flow

1. Operator (Human/Bot) creates a branch.
2. Operator (Human/Bot) creates a Pull Request.
3. PR merged and approved.
4. GitOps tool polls for changes (ArgoCD).
5. Changes are applied to the cluster.

Flux v2

• Flux v2 is a GitOps tool that synchronizes configuration from a Git repository into a Kubernetes cluster.
• Ability to deploy:
  • Kustomize,
  • Helm Charts, and
  • Yaml Manifests.
• Flux has a CLI tool for installing and interacting with Flux.

CRDs and Flux

• Flux is stateless and uses Custom Resources (CR) to store its state of functionality.
• Custom Resource Definitions are a way to extend the functionality of Kubernetes by allowing you to create API objects and operators.
• Allows multiple ways to interact with Flux:
  • Flux CLI,
  • Applying Kubernetes objects, and
  • Applying changes to the Git Repo.

Flux Architecture