CIDR specifies an IP address range with a network address and prefix length. Kubernetes uses distinct CIDR ranges for nodes, Pods, and Services, and these ranges must remain unique. section 6.1
Map each Kubernetes CIDR to its operational owner:
- Nodes CIDR identifies the infrastructure subnet and is managed by the cloud provider or network administrator. section 6.1
- Pod CIDR, also called Cluster-CIDR, assigns Pod addresses through the container network interface. section 6.1
- Service CIDR, also called Service-Cluster-IP-Range, supplies stable virtual addresses for Services and is configured by the API server. section 6.1
Reconfiguring a Service CIDR
Change the Service range to 100.96.0.0/16, recreate the Kubernetes and kube-dns Services, set kube-dns to 100.96.0.10, update the kubelet configuration, and verify a new Pod receives that DNS address. Inside the Pod, /etc/resolv.conf should list nameserver 100.96.0.10; nslookup can then confirm DNS resolution. section 6.1
