Kubernetes provides powerful networking abstractions hiding underlying complexity. Services provide stable endpoints for ephemeral pods. Ingress routes external traffic to appropriate services. Network policies control traffic flow for security. Understanding these primitives enables building secure, scalable applications.
Service Types and Use Cases
ClusterIP services provide internal-only endpoints for service-to-service communication. NodePort exposes services on node IPs for simple external access. LoadBalancer integrates with cloud load balancers for production traffic. ExternalName maps services to external DNS names.
- Use ClusterIP for internal services that don't need external access
- Prefer Ingress over NodePort for HTTP/HTTPS traffic with routing rules
- LoadBalancer services create cloud resources with associated costs
- Headless services enable direct pod addressing for stateful workloads
- Service mesh adds advanced traffic management beyond basic services
Network Policy Essentials
Network policies implement microsegmentation controlling pod-to-pod traffic. Default deny policies block all traffic except explicitly allowed. Namespace isolation prevents cross-namespace communication. Policies require CNI plugins supporting network policies—not all do by default.