VMware Telco Cloud Platform RAN is based on VMware Tanzu Basic for RAN. Tanzu Basic for RAN is responsible for the life cycle management of Kubernetes clusters on top of the Telco Cloud Platform RAN architecture. A Tanzu Kubernetes cluster is an opinionated installation of Kubernetes open-source software that is built and supported by VMware.

The following diagram shows different hosts and components of the Tanzu Basic for RAN architecture:

Figure 1. Tanzu Basic for RAN Architecture
Tanzu Basic for RAN Architecture

Tanzu Basic for RAN Control Plane

The Kubernetes control plane runs as pods on the Kubernetes Control Plane node. The Kubernetes Control Plane node comprises the following components:

  • Etcd: Etcd is a simple, distributed key-value store that stores the Kubernetes cluster configuration, data, API objects, and service discovery details. For security reasons, etcd must be accessible only from the Kubernetes API server.

  • Kube-API-Server: The Kubernetes API server is the central management entity that receives all API requests for managing Kubernetes objects and resources. The API server serves as the frontend to the cluster and is the only cluster component that communicates with the etcd key-value store.

    For added redundancy and availability, place a load balancer for the control plane nodes. The load balancer performs health checks of the API server to ensure that external clients such as kubectl connect to a healthy API server even during the cluster degradation.

  • Kube-Controller-Manager: The Kubernetes controller manager is a daemon that embeds the core control loops shipped with Kubernetes. A control loop is a non-terminating loop that regulates the state of the system. In Kubernetes, a controller is a control loop that watches the shared state of the cluster through the API server and moves the current state to the desired state.

  • Kube-Scheduler: Kubernetes schedulers know the total resources available in a Kubernetes cluster and the workload allocated on each worker node in the cluster. The API server invokes the scheduler every time there is a need to modify a Kubernetes pod. Based on the operational service requirements, the scheduler assigns the workload on a node that best fits the resource requirements.

Tanzu Basic for RAN Data Plane

5G RAN workloads such as CNFs run on worker nodes. Worker nodes run as VMs. A worker node requires the container runtime, kube-proxy, and kubelet daemon to function as a member of the Kubernetes cluster. Depending on the type of Telco workloads, worker nodes may require advanced network features such as multiple network interfaces, Container Networking Interface (CNI), SR-IOV, exclusive CPU core assignment, and NUMA pinning.