Data Plane: This plane is responsible for the actual handling of network traffic. In a service mesh, this is typically implemented using lightweight proxies (like Envoy or linkerd-proxy) deployed as sidecars alongside each service instance. These proxies intercept all inbound and outbound traffic for the service.
Control Plane: This plane manages and configures the data plane. It provides functionalities like:
> Service Discovery: Maintaining a registry of available services and their endpoints.
> Traffic Management: Defining routing rules, load balancing policies, and fault injection.
> Security: Managing certificates and enforcing access policies.
> Observability: Collecting metrics and logs from the data plane.
The control plane does not directly process traffic. It pushes configurations to the data plane proxies, which then enforce those configurations.
*****
A) While certificate lifecycle management is a control plane function, the control plane doesn't use proxies to manage it. The control plane typically provides certificates to the data plane proxies. Also, the data plane Envoy sidecars, which are network proxies deployed alongside each service instance, handle traffic routing based on the configuration provided by the control plane.
B) The control plane does not process inter-service network traffic. That's the core responsibility of the data plane.
D) The data plane and control plane are tightly coupled. The control plane configures the data plane. They do not operate independently. Also, service discovery is a core function of the control plane, not the data plane (Envoy). Traffic routing policies are also managed by the control plane and enforced by the data plane.