Anatomy of a Kubernetes Manifest: The Four Essential Structure Fields

# These four fields are REQUIRED in every Kubernetes manifest
apiVersion: apps/v1        # Which API group/version defines this kind
                           # v1 = core (Pod, Service, ConfigMap, Secret)
                           # apps/v1 = Deployment, StatefulSet, DaemonSet
                           # networking.k8s.io/v1 = Ingress, NetworkPolicy

kind: Deployment           # The object type — must match what apiVersion supports

metadata:                  # Object identity
  name: my-app             # Required — unique within namespace
  namespace: production    # Optional — defaults to 'default'
  labels:                  # Optional but critical — used for selectors
    app: my-app
    version: v1
  annotations:             # Optional — metadata for tools, not selectors
    description: "Main application deployment"

spec:                      # Desired state — structure varies by kind
  replicas: 3
  # ... rest of spec

# The API server also adds 'status' — you never write this, K8s manages it
status:                    # Current actual state (managed by K8s)
  availableReplicas: 3
  readyReplicas: 3

kubectl api-resources | grep deployment    # Shows: apps  true  Deployment
kubectl api-versions | grep apps           # Shows: apps/v1
kubectl explain deployment                 # Shows apiVersion, kind, fields