control plane
also: management plane, control pane
The set of components and processes that make decisions about how to manage and orchestrate a system, as opposed to the data plane which handles the actual workload traffic.
The control plane consists of management and decision-making systems that determine policies, configurations, and operations for infrastructure. In Kubernetes, for example, the control plane includes the API server, scheduler, and controller manager that decide which pods run where and how to maintain desired state.
The control plane is distinct from the data plane (or data path), which performs the actual work of processing user traffic and workloads. A control plane decision might be "scale this service to 5 replicas," while the data plane executes that by running containers and forwarding network traffic between them.
Example: In a load balancer, the control plane handles configuration and health checks, while the data plane forwards actual network packets to backend servers. If the control plane detects a server is down, it updates the data plane to stop sending traffic there.