Terminology
| Term | Meaning |
|---|---|
| Kubernetes control plane | The Kubernetes control plane is the collection of pods that manage containerized workloads on the worker nodes in a cluster. |
| Kubernetes control plane node | This is the virtual or physical machine that hosts the Kubernetes control plane, formerly known as a master node. |
| Server node | In Rancher terminology, a server node is a Kubernetes control plane node. |
| Kubernetes node or worker node | Also called a worker node, a Kubernetes node is a virtual or physical
machine that hosts containerized workloads in a cluster. To reduce ambiguity, we refer to this strictly as a worker node in this document. |
| Agent node | In Rancher terminology, an agent node is a Kubernetes worker node. |
| Contrail compute node | This is equivalent to a worker node. It is the node where the Contrail vRouter is providing the data plane function. |
| Network control plane | The network control plane provides the core SDN capability. It uses
BGP to interact with peers such as other controllers and gateway
routers, and XMPP to interact with the data plane components. CN2 supports a centralized network control plane architecture where the routing daemon runs centrally within the Contrail controller and learns and distributes routes from and to the data plane components. This centralized architecture facilitates virtual network abstraction, orchestration, and automation. |
| Network configuration plane | The network configuration plane interacts with Kubernetes control plane components to manage all CN2 resources. You configure CN2 resources using custom resource definitions (CRDs). |
| Network data plane | The network data plane resides on all nodes and interacts with containerized workloads to send and receive network traffic. Its main component is the Contrail vRouter. |
| Contrail controller | This is the part of CN2 that provides the network configuration and
network control plane functionality. This name is purely conceptual – there is no corresponding Contrail controller object or entity in the UI. |
| Contrail controller node | This is the control plane node or worker node where the Contrail controller resides. In some Kubernetes distributions, the Contrail controller resides on control plane nodes. In other distributions, the Contrail controller resides on worker nodes. |
| Central cluster | In a multi-cluster deployment, this is the central Kubernetes cluster that houses the Contrail controller. |
| Workload cluster | In a multi-cluster deployment, this is the distributed cluster that contains the workloads. |