# Exhaustive Service reference (v1).
# A Service is a stable virtual endpoint in front of pods: one DNS name and
# one cluster IP that load-balances to the currently Ready pods behind it.
# Pods come and go; the Service name (app-service.example.svc.cluster.local)
# never changes.
apiVersion: v1
kind: Service
metadata:
  name: app-service
  namespace: example
  labels:
    app: app
  annotations:
    description: "exhaustive service example"
spec:
  # selector: pods carrying these labels receive traffic. Empty selector =
  # no automatic endpoints (pair with a hand-written EndpointSlice to aim at
  # an external address - see endpointslice.yaml).
  selector:
    app: app
  ports:
    - name: http
      # protocol: TCP (default), UDP, or SCTP. Each port entry needs one.
      protocol: TCP
      # port: the port clients connect to on the Service IP.
      port: 80
      # targetPort: the port on the pod. Number or container port NAME
      # (names decouple the Service from container port renumbering).
      # Omit when it equals `port`.
      targetPort: http
      # nodePort: fixed node port for type NodePort/LoadBalancer (range
      # 30000-32767). Omit for auto-assignment.
      # nodePort: 30080
      # appProtocol: protocol hint for the payload (http, https, grpc, h2c,
      # ws...). Used by meshes and LBs, ignored by plain kube-proxy routing.
      appProtocol: http
    - name: metrics
      protocol: TCP
      port: 9090
      targetPort: 9090
  # type: ClusterIP (default, internal VIP), NodePort (also open a fixed port
  # on every node), LoadBalancer (NodePort + cloud LB in front),
  # ExternalName (DNS alias, no proxying - see below).
  type: ClusterIP
  # clusterIP: pin the virtual IP. "None" makes the Service headless: no VIP,
  # DNS returns pod IPs directly (required base for StatefulSets).
  # clusterIP: None
  # clusterIPs / ipFamilies / ipFamilyPolicy: dual-stack control.
  # ipFamilies: [IPv4] (default), [IPv6], or [IPv4, IPv6].
  # ipFamilyPolicy: SingleStack (default), PreferDualStack, RequireDualStack.
  # ipFamilies:
  #   - IPv4
  # ipFamilyPolicy: SingleStack
  # sessionAffinity: None (default, spread every connection) or ClientIP
  # (same client IP sticks to one pod).
  sessionAffinity: None
  # sessionAffinityConfig: stickiness TTL for ClientIP affinity.
  # sessionAffinityConfig:
  #   clientIP:
  #     timeoutSeconds: 10800
  # publishNotReadyAddresses: send traffic to not-Ready pods too. Needed for
  # peer discovery where members must find each other before anyone is Ready.
  publishNotReadyAddresses: false
  # internalTrafficPolicy: Cluster (default, route to pods on any node) or
  # Local (only pods on the receiving node - preserves source IP, drops
  # traffic on nodes without local pods).
  internalTrafficPolicy: Cluster
  # --- NodePort / LoadBalancer extras (ignored by pure ClusterIP) ---
  # externalTrafficPolicy: Cluster (default) or Local. Local preserves the
  # client source IP but drops traffic arriving on nodes with no local pod.
  # externalTrafficPolicy: Cluster
  # healthCheckNodePort: fixed node port for the LB health check (Local
  # policy). Omit for auto-assignment.
  # healthCheckNodePort: 32111
  # allocateLoadBalancerNodePorts: set false to skip node-port allocation on
  # a LoadBalancer (when the LB routes straight to pods). Default true.
  # allocateLoadBalancerNodePorts: true
  # loadBalancerIP: request a specific IP from the cloud provider. Provider
  # support varies; most now prefer annotations or IP pools.
  # loadBalancerIP: 203.0.113.10
  # loadBalancerSourceRanges: client CIDRs allowed through the cloud LB.
  # Unset = world-open. This is the cloud firewall in front of the Service.
  # loadBalancerSourceRanges:
  #   - 203.0.113.0/24
  # loadBalancerClass: use a custom LB implementation instead of the cloud
  # default (e.g. MetalLB speaker). The named controller must be installed.
  # loadBalancerClass: example.com/custom-lb
  # trafficDistribution: hint how to prefer endpoints (PreferClose = same
  # zone first). Best-effort, kube-proxy dependent.
  # trafficDistribution: PreferClose
  # --- other types ---
  # externalIPs: extra IPs (already routed to nodes) that also serve this
  # Service. Traffic arriving there is proxied like ClusterIP traffic.
  # externalIPs:
  #   - 203.0.113.20
  # ExternalName type: no proxying at all - DNS CNAME to the target.
  # Ports are informational. Used to reference outside names under a stable
  # in-cluster name.
  # type: ExternalName
  # externalName: db.example.com