# In Cilium's default cluster-pool IPAM mode, what assigns each node its pod CIDR?

Cilium, Hard (Expert), Architecture. https://k8wiz.com/uquiz/in-ciliums-default-cluster-pool-ipam-mode-what-assigns-each-node-its-pod-cidr

- A. kube-controller-manager, through the Node object's spec.podCIDR
- B. The cloud provider's VPC
- C. The Cilium operator, which records it in the node's CiliumNode resource
- D. Each agent picks a random free range at startup

**Answer:** The Cilium operator, which records it in the node's CiliumNode resource

**Explanation:** In cluster-pool mode the operator splits clusterPoolIPv4PodCIDRList into per-node blocks and writes them to each CiliumNode. The agent then hands out pod IPs from its block. The 'kubernetes' IPAM mode uses spec.podCIDR from kube-controller-manager instead, and cloud modes such as ENI or Azure take IPs from the provider.