HELM Controller

In this guide, we’ll dive into the Flux Helm Controller and its interaction with the Source Controller to manage Helm charts in a GitOps workflow. You’ll learn how to fetch Helm artifacts, define HelmRelease resources, and understand the responsibilities of the Helm Controller.

Source Controller: Fetching Helm Charts

The Source Controller in Flux can retrieve Helm charts from multiple source types and package them as tarballs or YAML index files. Common source types include Git repositories, OCI registries, S3 buckets, and Helm repositories (e.g., Bitnami, Artifactory).

Source Type	Description	Format	Example Provider
GitRepository	Charts stored in Git	`.tar.gz`	GitHub, GitLab
HelmRepository	Official Helm chart repos	YAML index files	Bitnami, Artifactory
OCI Registry	OCI-compliant chart registry	OCI artifacts	GitHub Container Registry
S3 Bucket	Charts in cloud object storage	`.tar.gz`	AWS S3, MinIO

# Git-based Helm charts
flux create source git my-helm-charts \
  --url https://github.com/sidd-harth/charts \
  --branch main

# Bitnami Helm repository with TLS certs
flux create source helm bitnami \
  --url https://charts.bitnami.com/bitnami \
  --cert-file=./cert.crt \
  --key-file=./key.crt \
  --ca-file=./ca.crt

Ensure your credentials (--cert-file, --key-file, --ca-file) are stored securely and referenced via Kubernetes Secrets.

After a reconciliation cycle, inspect the contents of the Source Controller’s data directory:

kubectl -n flux-system exec -it source-controller -- sh
~ # tree data/
data/
├── gitrepository
│   └── flux-system
│       └── my-helm-charts
│           ├── 1b31558bb1a701c7592652bbc9e3.tar.gz
│           └── latest.tar.gz
├── helmrepository
│   └── flux-system
│       └── bitnami
│           ├── index-e6dc924894f5f871db9b968.yaml
│           └── index.yaml

Defining a HelmRelease

A HelmRelease is a Flux custom resource that declares the desired state of a Helm chart deployment. The Helm Controller watches these resources and orchestrates Helm operations accordingly. Create a HelmRelease resource:

flux create helmrelease chart-z-release \
  --source HelmRepository/bitnami \
  --chart chart-z \
  --chart-version 1.2.3 \
  --values values.yaml

This command generates a HelmChart object, which the Source Controller will reconcile and produce as an artifact:

apiVersion: source.toolkit.fluxcd.io/v1beta2
kind: HelmChart
metadata:
  name: flux-system-chart-z-release
spec:
  interval: 1m0s
  chart: chart-z
  reconcileStrategy: ChartVersion
  sourceRef:
    kind: HelmRepository
    name: bitnami
    version: "1.2.3"
status:
  artifact:
    path: helmchart/flux-system/flux-system-chart-z-release/chart-z-release-1.2.3.tgz
    revision: 1.2.3
    url: http://source-controller-flux-system.svc.cluster.local/.helmchart/flux-system/flux-system-chart-z-release/chart-z-release-1.2.3.tgz

Verify the published chart artifact:

kubectl -n flux-system exec -it source-controller -- sh
~ # tree data/
data/
├── gitrepository
│   └── flux-system
│       └── my-helm-charts
│           ├── 1b31558bb1a701c7592652bbc9e3.tar.gz
│           └── latest.tar.gz
├── helmrepository
│   └── flux-system
│       └── bitnami
│           ├── index-e6dc924894f5f871db9b968.yaml
│           └── index.yaml
└── helmchart
    └── flux-system-chart-z-release
        ├── chart-z-release-1.2.3.tgz
        └── latest.tar.gz

Helm Controller Responsibilities

The Flux Helm Controller automates the lifecycle of Helm releases:

Watches HelmRelease CRs and reconciles them into HelmChart artifacts.
Retrieves packaged charts from the Source Controller.
Executes Helm commands: install, upgrade, test, rollback, and uninstall.
Supports automatic rollbacks on failed deployments.
Cleans up resources when a HelmRelease is deleted.

Deleting a HelmRelease object will trigger the uninstallation of the associated release. Backup any persistent data before removal.

GitOps Overview

Flux Overview

Source and Kustomize Controller

Helm Controller and OCI Registry

Image Automation Controller

Secret Management & Sign Verification

Notification Controller

Monitoring & User Interface

Source Controller: Fetching Helm Charts

Defining a HelmRelease

Helm Controller Responsibilities

Links and References

Watch Video

​Source Controller: Fetching Helm Charts

​Defining a HelmRelease

​Helm Controller Responsibilities

​Links and References

Watch Video

Source Controller: Fetching Helm Charts

Defining a HelmRelease

Helm Controller Responsibilities

Links and References