Networking — Cheat Sheet
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Cheat Sheet · AiCanCode.org
Networking
Kubernetes1 topicsQuick revision reference
1
Services & Networking
A Kubernetes Service provides a stable DNS name and IP for a set of pods. ClusterIP for internal, NodePort for development, LoadBalancer for production external traffic, and Ingress for HTTP routing.
- ✓Services provide stable DNS names for ephemeral pods — ClusterIP for internal, LoadBalancer for external.
- ✓Service selector labels must exactly match pod labels — mismatched labels = no traffic.
- ✓Ingress routes HTTP/HTTPS traffic by host and path — one external IP for multiple services.
- ✓CoreDNS auto-creates DNS records: service-name.namespace.svc.cluster.local.
- ✓kube-proxy maintains iptables/IPVS rules on each node to load-balance service traffic across pod IPs.
- ✓Headless services (clusterIP: None) return pod IPs directly via DNS — used by StatefulSets.
service.yaml — ClusterIP, LoadBalancer, NodePort
# ClusterIP (default) — internal only
apiVersion: v1
kind: Service
metadata:
name: my-api
spec:
type: ClusterIP # accessible only within the cluster
selector:
app: my-api # routes to pods with label app=my-api
ports:
- port: 80 # service port (what clients connect to)
targetPort: 8080 # pod's containerPort
# DNS: my-api.default.svc.cluster.local:80
# Or within same namespace: my-api:80
---
# LoadBalancer — provisions cloud load balancer (GKE, EKS, AKS)
apiVersion: v1
kind: Service
metadata:
name: my-api-external
spec:
type: LoadBalancer
selector:
app: my-api
ports:
- port: 80
targetPort: 8080
# After creation:
# kubectl get svc my-api-external
# NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S)
# my-api-external LoadBalancer 10.96.24.51 34.102.145.100 80:32045/TCP
# ↑ cloud LB IP (may take ~1 min)
---
# NodePort — exposes on each node's IP at a static port (30000-32767)
spec:
type: NodePort
selector:
app: my-api
ports:
- port: 80
targetPort: 8080
nodePort: 31000 # access via: NodeIP:31000Learn this free with Aria, your AI tutor → AiCanCode.org/learn/kubernetes