Feature Description

The PCF is built on the Kubernetes cluster strategy, which implies that it has adopted the native concepts of containerization, high availability, scalability, modularity, and ease of deployment. To achieve the benefits offered by Kubernetes, PCF uses the construct that includes the components such as pods and services.

Depending on your deployment environment, PCF deploys the pods on the virtual machines that you have configured. Pods operate through the services that are responsible for the intrapod communications. If the machine hosting the pods fail or experiences network disruption, the pods are terminated or deleted. However, this situation is transient and PCF spins new pods to replace the invalid pods.

The following workflow provides a high-level visibility into the host machines, and the associated pods and services. It also represents how the pods interact with each other. The representation might defer based on your deployment infrastructure.

Communication Workflow of Pods

The Protocol VM hosts the rest-ep, diameter-ep, and ldap-ep pod that governs the ingress (incoming) and egress (outgoing) traffic on the interfaces. The pods responsible for the operations and management processes reside in the OAM VM and, the Service VM hosts the pcf-engine. The session VMs hosts the pods that operate as the databases to store the data accessed by the pods. The illustration also depicts the services which the pods use to channel the interactions. The pods communicate over the gRPC interface.

Note
Typically, multiple instances of the Protocol and OAM VMs are created to ensure resiliency.

Kubernetes deployment includes the kubectl command-line tool to manage the resources in the cluster. You can manage the pods, nodes, and services using the CLI.

For performing the maintenance activities, you can use the kubectl drain command to withdraw a node voluntarily. This command prepares the node by evicting or assigning the associated pods to another node with sufficient resources. You can run the kubectl drain on individual or multiple nodes concurrently.

For generic information on the Kubernetes concepts, see the Kubernetes documentation.

For more information on the Kubernetes components in PCF, see the following.