Flux CD

kdef ships a Kubernetes controller that integrates natively with Flux CD. You define a KdefRelease CR pointing at a Flux GitRepository, and the controller handles rendering and applying on every new revision.

Install the controller

git clone https://github.com/gsid-nl/kdef.git
cd kdef

helm install kdef-controller ./flux-controller/chart \
  --namespace flux-system

The controller registers the kdef.gsid.nl/v1alpha1 API group and runs in the flux-system namespace alongside Flux’s own controllers.

Point it at a repo

1. The GitRepository

apiVersion: source.toolkit.fluxcd.io/v1
kind: GitRepository
metadata:
  name: my-app
  namespace: flux-system
spec:
  interval: 1m
  url: https://github.com/example/my-app.git
  ref:
    branch: main

2. The KdefRelease

apiVersion: kdef.gsid.nl/v1alpha1
kind: KdefRelease
metadata:
  name: my-app
  namespace: flux-system
spec:
  sourceRef:
    kind: GitRepository
    name: my-app
  path: ./k8s/
  interval: 5m
  prune: true

That’s it. The controller will:

1. Watch the GitRepository for new revisions
2. Download and extract the artifact
3. Run kdef render on the .kdef files in path
4. Apply the rendered manifests via server-side apply
5. Prune resources that dropped out of the output (when prune: true)

Environment overrides

Pass --env through to the render:

spec:
  env: production       # loads environments/production.kdef

Variable overrides

spec:
  set:
    image_tag: "v2.0.0"
    replicas: "3"

For complex values (lists, maps), mount them from a ConfigMap or Secret:

spec:
  valuesFrom:
    kind: Secret       # or ConfigMap
    name: my-app-values
    key: values.json   # default

Suspend and resume

spec:
  suspend: true

Useful during incidents or deliberate drift investigations.

Check status

kubectl get kdefreleases -n flux-system

# NAME     READY   STATUS                                    REVISION       AGE
# my-app   True    Applied revision: main@sha256:abc123...   main@sha...    5m

CRD reference

Field	Type	Required	Description
sourceRef.kind	string	yes	GitRepository, OCIRepository, or Bucket
sourceRef.name	string	yes	Name of the Flux source
sourceRef.namespace	string	no	Namespace of the source (defaults to KdefRelease namespace)
path	string	no	Path within the artifact to the kdef project directory
env	string	no	Environment name — loads environments/<env>.kdef
set	map	no	Variable overrides (--set equivalent)
valuesFrom.kind	string	no	ConfigMap or Secret
valuesFrom.name	string	no	Name of the ConfigMap/Secret
valuesFrom.key	string	no	Key in data (defaults to values.json)
interval	duration	yes	Reconciliation interval (e.g. 5m, 1h)
prune	bool	no	Delete resources that dropped out of output
targetNamespace	string	no	Override namespace for all resources
serviceAccountName	string	no	ServiceAccount for impersonation
suspend	bool	no	Pause reconciliation

A complete real-world example

A multi-app repo (see Multi-app layout) deployed with one KdefRelease per environment:

---
apiVersion: kdef.gsid.nl/v1alpha1
kind: KdefRelease
metadata:
  name: platform-staging
  namespace: flux-system
spec:
  sourceRef:
    kind: GitRepository
    name: platform
  path: ./
  env: staging
  interval: 2m
  prune: true
---
apiVersion: kdef.gsid.nl/v1alpha1
kind: KdefRelease
metadata:
  name: platform-production
  namespace: flux-system
spec:
  sourceRef:
    kind: GitRepository
    name: platform
  path: ./
  env: production
  interval: 5m
  prune: true

Staging reconciles every 2 minutes for fast feedback. Production every 5 minutes.