This page documents all Flux Kustomization resources used to manage the cluster configuration with GitOps.
What is a Kustomization? A Flux Kustomization is a custom resource that tells Flux how to reconcile Kubernetes manifests from a Git repository. It watches a source (like a GitRepository) and applies the manifests found at the specified path.
Core Kustomization Resources flux-system Kustomization The root Kustomization that bootstraps the entire cluster:
cluster/kimawesome/flux-system/gotk-sync.yaml
apiVersion : kustomize.toolkit.fluxcd.io/v1 kind : Kustomization metadata : name : flux-system namespace : flux-system spec : interval : 10m0s path : ./cluster/kimawesome prune : true sourceRef : kind : GitRepository name : flux-system
How often Flux checks the source for changes. Format: 10m0s, 1h, 30s
Path within the Git repository to reconcile. Relative to repository root.
When true, Flux removes resources from the cluster that are no longer in Git.
Reference to the source (GitRepository, Bucket, or OCIRepository) containing the manifests.
overlays Kustomization Manages the environment-specific overlay configurations:
cluster/kimawesome/kustomization.flux.yaml
apiVersion : kustomize.toolkit.fluxcd.io/v1beta2 kind : Kustomization metadata : name : overlays namespace : flux-system spec : interval : 10m path : "./overlays/kimawesome" prune : true sourceRef : kind : GitRepository name : flux-system
This Kustomization applies all environment overlays for the kimawesome cluster.
infrastructure Kustomization Manages infrastructure components with dependencies:
overlays/kimawesome/infrastructure/kustomization.flux.yaml
apiVersion : kustomize.toolkit.fluxcd.io/v1beta2 kind : Kustomization metadata : name : infrastructure namespace : flux-system spec : interval : 10m path : "./overlays/kimawesome/infrastructure" prune : true sourceRef : kind : GitRepository name : flux-system dependsOn : - name : metallb namespace : kube-system
List of Kustomizations or HelmReleases that must be ready before this one is applied. dependsOn : - name : metallb namespace : kube-system - name : cert-manager namespace : cert-manager
Configuration Fields Source Reference The sourceRef field tells Flux where to find the manifests:
GitRepository Source
Bucket Source
OCI Repository
sourceRef : kind : GitRepository name : flux-system namespace : flux-system # optional
Health Checks Configure custom health checks for resources:
spec : healthChecks : - apiVersion : apps/v1 kind : Deployment name : my-app namespace : default timeout : 5m
Post-Build Variable Substitution Use variable substitution in manifests:
spec : postBuild : substitute : CLUSTER_NAME : "kimawesome" DOMAIN : "kim.tec.br" substituteFrom : - kind : ConfigMap name : cluster-vars
Then in your manifests:
apiVersion : v1 kind : ConfigMap metadata : name : app-config data : cluster : ${CLUSTER_NAME} domain : ${DOMAIN}
Reconciliation Behavior Automatic Reconciliation
Flux checks the source at the interval specified in spec.interval
If changes are detected, Flux applies them automatically
Resources are created, updated, or deleted based on the manifests
Manual Reconciliation Force immediate reconciliation:
flux reconcile kustomization flux-system flux reconcile kustomization overlays --with-source
Suspension Temporarily stop reconciliation:
flux suspend kustomization infrastructure flux resume kustomization infrastructure
Dependencies and Ordering Kustomizations can depend on other Kustomizations or HelmReleases:
spec : dependsOn : - name : cert-manager namespace : cert-manager - name : metallb namespace : kube-system
Flux ensures dependencies are ready before applying dependent resources.
Common Patterns Multi-Environment Setup cluster/ ├── base/ # Base Kustomization └── production/ # Production overlay Kustomization └── staging/ # Staging overlay Kustomization
Namespace Isolation Each namespace gets its own Kustomization:
apiVersion : kustomize.toolkit.fluxcd.io/v1 kind : Kustomization metadata : name : apps-namespace namespace : flux-system spec : interval : 10m path : ./apps prune : true targetNamespace : applications sourceRef : kind : GitRepository name : flux-system
Troubleshooting Check Kustomization Status flux get kustomizations kubectl describe kustomization flux-system -n flux-system
View Applied Resources flux tree kustomization flux-system
Check Events kubectl get events -n flux-system --sort-by= '.lastTimestamp'