getting-started

Getting Started: Cluster-to-Disk Pipeline

This example demonstrates the complete Kure pipeline that transforms a declarative Cluster definition into on-disk Kubernetes manifests ready for GitOps reconciliation.

Pipeline Steps

1. Build a Cluster (ClusterBuilder)

Use the fluent ClusterBuilder API to define your cluster hierarchy:

• Cluster — top-level container with a name and GitOps configuration
• Node — a directory-level grouping (e.g., infrastructure, applications)
• Bundle — a reconciliation unit within a node, holding applications and a source reference
• Application — a workload described by an ApplicationConfig implementation

The builder uses a copy-on-write pattern, so intermediate builder values can safely be reused to create divergent cluster configurations.

2. Create a Workflow Engine (FluxCD)

Kure supports pluggable workflow engines. This example uses fluxcd.NewWorkflowEngine to create a FluxCD engine with the defaults. Flux resource placement (integrated vs separate) is configured per call on layout.LayoutRules.FluxPlacement in Step 3, not on the engine. Every Kustomization's spec.path is the directory the layout writes its bundle to.

3. Generate a Layout (CreateLayoutWithResources)

The workflow engine walks the cluster tree, calls each ApplicationConfig.Generate() to produce Kubernetes objects, generates Flux Kustomization resources, and assembles everything into a ManifestLayout tree.

4. Write to Disk (WriteManifest)

layout.WriteManifest serialises the layout tree as YAML files organised into directories with kustomization.yaml files at each level, ready for Flux to reconcile.

Running

go run ./examples/getting-started/

By default, output is written to a temporary directory. Set OUT_DIR to control the output location:

OUT_DIR=./output go run ./examples/getting-started/

Output Structure

clusters/
  staging/
    infrastructure/
      cache-deployment-redis.yaml
      cluster-namespace-cache.yaml
      cluster-namespace-web.yaml
      web-deployment-web-app.yaml
      web-service-web-app.yaml
      kustomization.yaml
    flux-system/
      flux-system-kustomization-platform-services.yaml
      kustomization.yaml

Implementing ApplicationConfig

Each application type implements the stack.ApplicationConfig interface:

type ApplicationConfig interface {
    Generate(*Application) ([]*client.Object, error)
}

The Generate method returns a slice of Kubernetes objects (Deployments, Services, ConfigMaps, etc.) that the layout writer serialises to YAML. See RedisConfig and WebAppConfig in main.go for complete examples.