The Four Networks + Service Types
Every Pod gets a unique, routable IP. Here's how the networking layers stack up.
Node Network
Physical/VM links
Pod Network
Overlay (CNI)
Service Network
Virtual IPs
External
Ingress traffic
Service Types
ClusterIP
Internal only. iptables rules.
Use: Backends, DBs
NodePort
Opens 30000-32767 on all nodes.
Use: Dev/test
LoadBalancer
Cloud LB (AWS NLB/ALB).
Use: Production
kube-proxy: iptables vs IPVS
iptables (Legacy)
O(n) rules. Falls over ~5000 services.
IPVS (Recommended)
O(1) hash. 100k+ services.
CNI Plugins
Flannel Simple
VXLAN overlay. No NetworkPolicy.
Calico Enterprise
BGP routing. Full policies.
Cilium eBPF
L7 policies, observability.