High Level of Kubernetes Architecture

In Kubernetes architecture, there are mainly two components: the Control plane and the Worker node. The Worker node can also be called the data plane.

We can interact with the control plane through CLI or GUI. Here, we mostly use CLI to interact with the control plane. The most important component in the control plane is the API Server.

API Server:

It validates every request from a client. If it is validated, then only forward the request to other components in the control plane. If it is not validated, it simply throws an error.

Kube Scheduler:

The scheduler always interacts with the API Server to fetch information. It works on the information given from the API Server and schedules information on a particular worker node.

The scheduled information is sent back to the API Server, and the kubelet from the API Server is going to fetch that information from one of the worker nodes.

Controller Manager:

It is responsible for node management. If any worker node fails due to some issues, inside worker nodes, some pods are running. It detects the problem and notifies the API Server and asks the scheduler where to schedule these pods.

The scheduler is going to work on it and send a response to the API Server; from the API Server, another worker node, kubelet, is going to collect the information about pods to schedule on the worker node. They are different controller managers, each one is responsible for a different task.

ETCD:

It is one component of the control plane. It stores values in key-value format and it is used for Kubernetes persistent storage for all cluster information.

Kubelet:

It is responsible for the life cycle of the container and also for scheduling pods on the worker node.

Kube Proxy:

Kube-Proxy is a network proxy that runs on each node in a Kubernetes cluster. It is responsible for maintaining network connectivity between services and pods.

POD:

A pod is a collection of one or more Linux containers and is the smallest unit of a Kubernetes application.