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What is Pattern-as-Code?

Pattern-as-Code (PaC) is a declarative approach to defining Kubernetes patterns and best practices as structured, machine-readable definitions.

Instead of documenting patterns in prose or tribal knowledge, Pattern-as-Code captures the architectural intent, resource relationships, and detection logic in YAML or JSON files that can be version-controlled, shared, and automatically enforced.

Core Concept​

Each Pattern-as-Code definition describes:

  • What resources are involved (Pods, Services, ConfigMaps, etc.)
  • How they relate to each other (references, dependencies, ownership)
  • What constitutes a violation or anti-pattern
  • Why it matters (severity, category, impact)

KubePattern uses these definitions to scan your cluster, identify existing configurations, and detect violations automatically.

Structure Overview​

A Pattern-as-Code definition typically contains:

Metadata​

{
  "metadata": {
    "name": "resource-limit-predictable-demands",
    "displayName": "Resource Limit Predictable Demands",
    "patternType": "FOUNDATIONAL",
    "severity": "WARNING",
    "category": "architecture",
    "description": "Ensures Pods have CPU and memory limits defined"
  }
}

Resource Definitions​

{
  "spec": {
    "resources": [
      {
        "resource": "Pod",
        "id": "target-pod",
        "leader": true
      },
      {
        "resource": "Deployment",
        "id": "owning-deployment"
      }
    ]
  }
}

Relationships​

{
  "relationships": [
    {
      "id": "pod-deployment-ownership",
      "type": "OWNED_BY",
      "resourceIds": ["target-pod", "owning-deployment"],
      "weight": 10,
      "required": true
    }
  ]
}

How KubePattern Uses Pattern-as-Code​

  1. Load Patterns: KubePattern fetches pattern definitions from the registry
  2. Scan Cluster: Analyzes your Kubernetes resources and their relationships
  3. Match Patterns: Compares cluster state against pattern definitions
  4. Detect Violations: Identifies resources that match anti-pattern criteria
  5. Generate Reports: Creates K8sPattern CRDs with findings and recommendations

Benefits​

  • Consistency: Standardized pattern definitions across teams and clusters
  • Automation: Automatic detection without manual audits
  • Version Control: Track pattern evolution in Git
  • Shareability: Public registry of community patterns
  • Extensibility: Create custom patterns for your organization
  • Documentation: Self-documenting architecture through code

Registry Structure​

Explore The Offiacial Pattern Registry

Pattern-as-Code is constantly evolving! Check the official registry for the latest patterns and contribute your own discoveries.

The official KubePattern registry organizes patterns in a simple structure:

kubepattern-registry/
├── definitions/
│   ├── resource-limit-predictable-demands.json
│   ├── health-probe.json
│   ├── table-not-referenced.json
│   └── ...
├── doc/
│   ├── resource-limit-predictable-demands.md
│   ├── health-probe.md
│   └── ...
├── K8sPatternCRD.yaml
├── doc-template.md
├── short-doc-template.md
└── kubepattern-resources.yaml

Each pattern definition in definitions/ has corresponding documentation in doc/ explaining the problem, solution, and implementation examples.

Example: Resource Limit Pattern​

Here's a simplified Pattern-as-Code definition:

{
  "version": "kubepattern.it/v1",
  "kind": "Pattern",
  "metadata": {
    "name": "resource-limit-predictable-demands",
    "severity": "WARNING",
    "category": "architecture"
  },
  "spec": {
    "message": "Pod {{target-pod.name}} is missing resource limits",
    "resources": [
      {
        "resource": "Pod",
        "id": "target-pod",
        "leader": true
      }
    ],
    "actors": ["target-pod"]
  }
}

When KubePattern scans your cluster and finds a Pod without resources.limits defined, it creates a K8sPattern CRD:

apiVersion: kubepattern.it/v1
kind: K8sPattern
metadata:
  name: resource-limit-my-pod
spec:
  name: "Resource Limit Predictable Demands"
  severity: WARNING
  message: "Pod my-pod is missing resource limits"
  resources:
    - name: my-pod
      namespace: default
      role: target-pod
      uid: abc-123