Kubernetes Networking

Kubernetes Networking

Kubernetes network model

• Cluster-wide IP address per pod
• Shared network namespace for containers in a pod
• Inter-pod communication without NAT
• Intra-pod communication via loopback
• Intra-host communication for node agents

kube-proxy provides per host LB for services

Ingress Controller enables user access to pods

Container Network Interface (CNI)

Kubernetes implements the Container Network Interface (CNI)

Network implementation can plug into CNI, e.g.

• kubenet
• calico
• cilium

Network plugins provide different features

Most plugins implement an overlay network (IP-in-IP)

Other plugins use a flat networking model, e.g.

• AWS EKS uses the VPC CNI plugin
• Azure AKS offers VNet CNI