# Exhaustive EndpointSlice reference (discovery.k8s.io/v1).
# EndpointSlices are the address lists behind a Service: each entry says
# "IP X serves port Y, ready or not". Normally the endpoint controller writes
# them automatically from the Service selector. You write one by hand in a
# single case: a selector-less Service pointing OUTSIDE the cluster (a host
# daemon, a LAN appliance, an external database). The pair looks like:
#   Service (no selector, same port names) + this EndpointSlice.
apiVersion: discovery.k8s.io/v1
kind: EndpointSlice
metadata:
  name: app-external-abc123
  namespace: example
  labels:
    # kubernetes.io/service-name: THE binding label. It must equal the
    # selector-less Service name - this is what attaches the slice to it.
    # The endpoint controller owns slices it creates; hand-written ones
    # just need this label to be picked up.
    kubernetes.io/service-name: app-external-service
    app: app
  annotations:
    description: "hand-written slice for an off-cluster backend"
# addressType: IPv4, IPv6, or FQDN. All endpoints in one slice share it -
# mix families with one slice per family.
addressType: IPv4
ports:
  - name: http
    # name: MUST match the Service port name it serves.
    protocol: TCP
    # port: the REAL backend port (may differ from the Service port - the
    # Service port is the in-cluster alias, this is where packets go).
    port: 8080
    # appProtocol: payload hint, mirrors the Service field.
    appProtocol: http
endpoints:
  # One entry per backend address. kube-proxy load-balances across the ones
  # whose conditions say ready+serving+terminating=false.
  - addresses:
      # addresses: one or more IPs (or a single DNS name for FQDN slices).
      - 192.168.1.50
    conditions:
      # ready: backend accepts traffic. False removes it from rotation
      # without deleting the entry (flap-friendly).
      ready: true
      # serving: the process is up. Differs from ready during shutdown:
      # serving=false + terminating=true = draining.
      serving: true
      # terminating: the endpoint is going away. Draining traffic, not dead.
      terminating: false
    # hostname: DNS name published for this endpoint (headless Services).
    # hostname: backend-1
    # targetRef: link back to the pod/node object (set automatically on
    # controller-managed slices; omit on hand-written ones).
    # targetRef:
    #   kind: Pod
    #   namespace: example
    #   name: app-67890abcde-fghij
    #   uid: 12345678-1234-1234-1234-123456789abc
    # nodeName: the node hosting this endpoint (topology-aware routing).
    # zone: override the endpoint zone (defaults from nodeName).
    # hints: topology hints for zone-aware routing (PreferClose).
    # hints:
    #   forZones:
    #     - name: zone-a