Networking
Module infographic
63 / 82

Revision poster: Pod IPs, Services, DNS, policy and ingress.

Infographic: the path from user through Ingress or Gateway and Service to a Pod, the four Service types, DNS and endpoints, and NetworkPolicy
Click the poster to enlarge it

The top row is the traffic path. The bottom row groups the supporting mechanisms.

  1. 1Every Pod has its own IP and reaches other Pods without NAT.
  2. 2A Service gives a stable virtual IP and name over changing Pods.
  3. 3ClusterIP is internal, NodePort opens a port on every node, LoadBalancer asks the cloud, ExternalName is an alias.
  4. 4CoreDNS resolves names; EndpointSlices list ready Pods only.
  5. 5NetworkPolicy starts open: add default deny, then explicit allows.
  6. 6Ingress or Gateway API routes HTTP from outside.

Self-check: cover the poster and answer

  • A Service exists but traffic gets a 503: what do you check first?
  • Why does a NetworkPolicy sometimes do nothing at all?

Pods get flat IPs, Services give stable names, policies restrict who may talk.

BackNext