This manifest is used to create a deployment, which is a Kubernetes resource that manages a set of pods with the same configuration. A deployment can also provide declarative updates, scaling, and rolling back for the pods. The created pods are not receiving traffic on port 80, because the manifest does not specify a service or a selector for the deployment. A service is another Kubernetes resource that defines a logical set of pods and a policy to access them. A selector is a label query that matches the pods that belong to the service. Four pods are created as a result of applying this manifest, because the manifest specifies replicas: 4 in the spec section of the deployment

The configuration plane is the function that enables CN2 to manage its resources and interact with the kube-api. The configuration plane is responsible for storing and managing all configuration data in a Contrail cluster. It provides APIs for other components to retrieve this data. This allows CN2 to manage its resources and interact with the kube-api.

Overlay virtual networks are virtual logical networks constructed on top of an existing network using network virtualization technologies45. They decouple network services from the physical networking and interconnection technologies on the underlay network45. Two true statements about overlay virtual networks are:

• Overlay virtual networks work well on an IP spine-and-leaf topology6. They can be created over underlay networks using network virtualization technologies4.
• Overlay virtual networks allow both Layer 2 and Layer 3 communication65. They can serve not only different services (such as multiple departments) of the same tenant but also different tenants4. References from Juniper site: Microsoft Learn, Huawei IP Encyclopedia, Network Insight