Kubernetes Manifest JSON and YAML Conversion

Kubernetes accepts both YAML and JSON for its resource manifests. While YAML is the standard convention in the Kubernetes ecosystem, JSON is useful for programmatic generation, API calls, and debugging.

A Kubernetes Deployment in YAML:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-app
  labels:
    app: web
    tier: frontend
spec:
  replicas: 3
  selector:
    matchLabels:
      app: web
  template:
    metadata:
      labels:
        app: web
    spec:
      containers:
        - name: web
          image: nginx:1.25
          ports:
            - containerPort: 80
          resources:
            limits:
              cpu: "500m"
              memory: "128Mi"
            requests:
              cpu: "250m"
              memory: "64Mi"

The JSON equivalent:

{
  "apiVersion": "apps/v1",
  "kind": "Deployment",
  "metadata": {
    "name": "web-app",
    "labels": {
      "app": "web",
      "tier": "frontend"
    }
  },
  "spec": {
    "replicas": 3,
    "selector": {
      "matchLabels": { "app": "web" }
    },
    "template": {
      "metadata": {
        "labels": { "app": "web" }
      },
      "spec": {
        "containers": [
          {
            "name": "web",
            "image": "nginx:1.25",
            "ports": [{ "containerPort": 80 }],
            "resources": {
              "limits": { "cpu": "500m", "memory": "128Mi" },
              "requests": { "cpu": "250m", "memory": "64Mi" }
            }
          }
        ]
      }
    }
  }
}

Practical tips:

• kubectl accepts both formats: kubectl apply -f deployment.yaml or kubectl apply -f deployment.json
• To convert existing resources: kubectl get deployment web-app -o json exports JSON
• CPU and memory values like "500m" and "128Mi" must be quoted in YAML to remain strings
• Kubernetes API responses are always JSON, making JSON familiarity essential for debugging

Multi-document YAML (separated by ---) is common in Kubernetes but has no JSON equivalent. Each document must be converted to a separate JSON file or placed in a JSON array.