Every Pod in an Anthos GKE cluster receives a Pod IP address. Pod IPs are routable within the cluster; whether they are reachable from outside depends on the cluster implementation. They use an address range separate from those for nodes and API servers, and for Services. section 10.2.1
The API server divides a Pod CIDR into unique ranges for nodes. A Pod receives an address from its node’s range, so its address changes if it moves to another node. Size the Pod CIDR for the maximum node count and the planned Pods per node. section 10.2.1
Plan for 30 Pods per node
Each node needs at least a /27 range, containing 32 addresses. The cluster Pod range must accommodate one such range for every node at the planned maximum size. section 10.2.1
Do not rely on a Pod IP as a stable Service address. A Service’s ClusterIP remains static and acts as a virtual IP for multiple Pods, even though individual Pod IPs can change. section 10.2.1
