> ## Documentation Index
> Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt
> Use this file to discover all available pages before exploring further.

# FluxCD Architecture Part1

> This article explores the high-level architecture of FluxCD and its core components within a Kubernetes cluster.

In this lesson, we’ll dive into the high-level architecture of **FluxCD** and examine how its core components collaborate within a Kubernetes cluster. By the end, you’ll understand:

* How FluxCD implements GitOps for continuous delivery
* The role of Flux controllers and CLI commands
* Observability and notification integration

## How FluxCD Operates in Kubernetes

FluxCD runs as an agent inside your Kubernetes cluster. Users typically interact via the [Flux CLI](https://fluxcd.io/docs/cmd/flux/) to:

1. **Create Sources**\
   Configure Git repositories, Helm charts, or OCI registries as reconciliation sources.
2. **Define Kustomizations**\
   Apply and manage Kubernetes manifests using Kustomize.
3. **Automate Image Updates**\
   Monitor container registries to automatically bump image tags in Git.

<Callout icon="lightbulb" color="#1CB2FE">
  FluxCD follows the GitOps pattern:

  * The **desired state** lives in a Git repository.
  * The **live state** resides in the Kubernetes cluster.
  * FluxCD continually syncs them for drift correction.
</Callout>

## Core Flux Controllers

FluxCD comprises several controllers that reconcile resources in Kubernetes. Here’s a quick overview:

| Controller                  | Responsibility                                   | Example CLI Command                                                                  |
| --------------------------- | ------------------------------------------------ | ------------------------------------------------------------------------------------ |
| Source Controller           | Tracks Git repos, Helm repositories, OCI images  | `flux create source git podinfo --url=https://github.com/stefanprodan/podinfo`       |
| Kustomize Controller        | Applies Kustomize overlays                       | `flux create kustomization podinfo --source=GitRepository/podinfo --path="./deploy"` |
| Helm Controller             | Installs and upgrades Helm charts                | `flux create helmrelease nginx --chart=nginx --target-namespace=default`             |
| Notification Controller     | Sends events and alerts via Slack, email, GitHub | Configure via `Notification` and `Alert` custom resources                            |
| Image Automation Controller | Automates container image updates in Git         | `flux create image policy podinfo --image-ref=ghcr.io/stefanprodan/podinfo`          |

## The GitOps Workflow

FluxCD continuously monitors your Git repositories and the cluster’s live state. When a commit or pull-request merge occurs:

1. **Webhook Trigger** (optional)\
   You can configure Git webhooks to notify FluxCD of new commits immediately.
2. **Reconciliation Loop**\
   Each controller fetches the latest manifests, compares them to the live cluster state, and applies any differences.
3. **Status Reporting**\
   Flux updates resource status back to Git (e.g., annotating commits), and emits events for observability.

<Frame>
  ![The image illustrates the architecture of FluxCD, showing the workflow from approving pull requests to syncing clusters with updated manifests, including interactions with GitHub, UI/CLI, and notification/metrics systems.](https://kodekloud.com/kk-media/image/upload/v1752877612/notes-assets/images/GitOps-with-FluxCD-FluxCD-Architecture-Part1/fluxcd-architecture-workflow-diagram.jpg)
</Frame>

## Observability & Notifications

FluxCD offers built-in metrics and alerts to help you monitor delivery pipelines:

* **Prometheus Metrics**\
  Expose metrics from each controller; scrape with Prometheus for real-time insights.
* **Grafana Dashboards**\
  Visualize Flux health and reconcile durations.
* **Notifications Controller**\
  Send alerts on sync failures or promotion events to Slack, email, or GitHub.

<Callout icon="triangle-alert" color="#FF6B6B">
  Ensure your cluster’s RBAC policies allow Flux to read Secrets and apply CRDs. Misconfigured permissions can prevent controllers from reconciling.
</Callout>

## Next Steps

In the next part, we’ll walk through installing FluxCD and bootstrapping your first GitOps repository. Until then, explore these resources:

* [FluxCD Official Documentation](https://fluxcd.io/docs/)
* [Weave GitOps UI](https://github.com/weaveworks/ui)
* [Prometheus User Guide](https://prometheus.io/docs/introduction/overview/)
* [Grafana Dashboards for Flux](https://grafana.com/grafana/dashboards?search=fluxcd)

Thank you for following along—see you in Part 2!

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