FluxCD Operator Reference

The Flux Operator manages Flux installations declaratively via two CRDs: FluxInstance (desired state) and FluxReport (observed state). It replaces the flux bootstrap imperative workflow with a fully GitOps-managed lifecycle.

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Installation

# Helm (recommended)
helm install flux-operator oci://ghcr.io/controlplaneio-fluxcd/charts/flux-operator \
  --namespace flux-system --create-namespace

# Terraform — see references/fluxcd-terraform.md

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FluxInstance

One instance per cluster. Must be named flux in the operator's namespace.

apiVersion: fluxcd.controlplane.io/v1
kind: FluxInstance
metadata:
  name: flux          # must be named 'flux' — only one per cluster
  namespace: flux-system
  annotations:
    fluxcd.controlplane.io/reconcileEvery: "1h"   # auto-update check
spec:
  distribution:
    version: "2.x"                         # semver range — tracks latest 2.x
    registry: "ghcr.io/fluxcd"
    imagePullSecret: "ghcr-registry-auth"  # optional, for private registries
  cluster:
    type: kubernetes        # kubernetes | openshift | k3s
    multitenant: false      # enables cross-namespace reference restrictions
    tenantDefaultServiceAccount: flux-reconciler
    networkPolicy: true     # adds NetworkPolicies to flux-system
    clusterDomain: "cluster.local"
  components:
    - source-controller
    - kustomize-controller
    - helm-controller
    - notification-controller
    - image-reflector-controller       # optional: required for image automation
    - image-automation-controller      # optional: required for image automation
    - source-watcher                   # optional: required for ArtifactGenerator
  sync:
    kind: OCIRepository                # OCIRepository (gitless) or GitRepository
    url: "oci://ghcr.io/my-org/fleet-manifests"
    ref: "latest"
    path: "clusters/production"
    pullSecret: "registry-auth"
  storage:
    class: "standard"
    size: "10Gi"

Cluster sizing

Size	Use case	Concurrency	Memory limit
small	dev/test, <10 tenants	5	512Mi
medium	staging, 10–50 tenants	10	1Gi
large	production, >50 tenants	20	3Gi

Set via kustomize.patches targeting the controller Deployments, or use spec.sharding for horizontal scaling.

Multi-tenancy

When multitenant: true:

• Controllers impersonate the specified service account for reconciliation
• Cross-namespace references are disabled by default
• Each tenant's Kustomization must set spec.serviceAccountName

Sync modes

Mode	spec.sync.kind	When to use
Gitless (OCI)	OCIRepository	Default for Flux Operator — immutable, signable
Git	GitRepository	Migrating from flux bootstrap

Both create a root Kustomization in flux-system that reconciles the configured path.

Kustomize patches

Apply patches to controller Deployments without forking the distribution:

spec:
  kustomize:
    patches:
      - target:
          kind: Deployment
          name: kustomize-controller
        patch: |
          - op: add
            path: /spec/template/spec/tolerations
            value:
              - key: dedicated
                operator: Equal
                value: flux
                effect: NoSchedule

Optional components

Component	Enables
image-reflector-controller	ImageRepository, ImagePolicy CRDs
image-automation-controller	ImageUpdateAutomation CRDs
source-watcher	ArtifactGenerator CRD (monorepo decomposition)

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FluxReport

Auto-updated every 5 minutes. Reports distribution version, component readiness, reconciler stats, and sync status.

# Check cluster-wide Flux health
kubectl get fluxreport flux -n flux-system -o yaml

# Key fields to inspect
kubectl get fluxreport flux -n flux-system -o jsonpath='{.status.conditions}'

Configure reporting interval:

metadata:
  annotations:
    fluxcd.controlplane.io/reconcileEvery: "5m"

---

Runtime ConfigMap

The flux-runtime-info ConfigMap holds cluster variables consumed via postBuild.substituteFrom across all Kustomizations.

apiVersion: v1
kind: ConfigMap
metadata:
  name: flux-runtime-info
  namespace: flux-system
  labels:
    reconcile.fluxcd.io/watch: Enabled    # triggers immediate reconciliation on change
  annotations:
    kustomize.toolkit.fluxcd.io/ssa: "Merge"  # preserves fields owned by Terraform
data:
  CLUSTER_NAME: "production-eu"
  CLUSTER_REGION: "eu-west-1"
  ENVIRONMENT: "prod"
  DOMAIN: "example.com"

The reconcile.fluxcd.io/watch: Enabled label causes any Kustomization with substituteFrom referencing this ConfigMap to immediately reconcile when the ConfigMap changes.

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Reconciliation triggers

Force immediate reconciliation on any Flux Operator resource:

kubectl annotate fluxinstance flux -n flux-system \
  fluxcd.controlplane.io/requestedAt="$(date -u +%Y-%m-%dT%H:%M:%SZ)" --overwrite

kubectl annotate fluxreport flux -n flux-system \
  fluxcd.controlplane.io/requestedAt="$(date -u +%Y-%m-%dT%H:%M:%SZ)" --overwrite

---

Tag promotion pattern

Use separate tags per environment — latest tracks the main branch (staging), latest-stable tracks release tags (production). Each FluxInstance references its environment's tag:

# staging FluxInstance
spec:
  sync:
    url: "oci://ghcr.io/my-org/fleet-manifests"
    ref: "latest"            # built from main branch

# production FluxInstance
spec:
  sync:
    url: "oci://ghcr.io/my-org/fleet-manifests"
    ref: "latest-stable"     # built from release tags only

CI pushes both tags — latest on every merge to main, latest-stable only on tagged releases. This gives staging automatic updates and production explicit promotion.

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Flux Web UI

The Flux Operator Helm chart bundles a Web UI that shows FluxInstance status, reconciler stats, and cluster sync state. Enable it via Helm values:

# values for flux-operator Helm chart
ui:
  enabled: true
  ingress:
    enabled: true
    host: flux.internal.example.com

Supports SSO via OIDC providers (Dex, Keycloak, Microsoft Entra ID, OpenShift). No additional installation — it is built into the operator Helm chart.

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Migration from flux bootstrap

1. Install the Flux Operator (helm install flux-operator ...)
2. Create a FluxInstance with sync.kind: GitRepository pointing to your existing bootstrap repo
3. Verify FluxReport shows all components Ready
4. Switch sync.kind to OCIRepository once you publish OCI artifacts from CI
5. Remove the old gotk-sync.yaml and gotk-components.yaml from Git

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Validation

# Check FluxInstance status
kubectl get fluxinstance flux -n flux-system
kubectl describe fluxinstance flux -n flux-system

# Check cluster-wide health
kubectl get fluxreport flux -n flux-system -o yaml

# Check controller pod health
kubectl get pods -n flux-system
kubectl logs -n flux-system deploy/source-controller | tail -50