Kubernetes Components

 Kubernetes Components

In this article we are gonna to see about kubernetes components which is most important when you are going to start your career in kubernetes platform. Here we have divided into two part one is Server/Master/Controller components and second is worker/Node components. Please read and enjoy this article if you want to give any feedback about your experience, we welcome.

Kubernetes components divided in two parts.

1. Master/Controller components

2. Worker/Node components

Master/Controller components:

kube-api Server:

The API server is a component of the Kubernetes control plane that exposes the Kubernetes API. The API server is the front end for the Kubernetes control plane.

etcd:

Consistent and highly-available key value store used as Kubernetes' backing store for all cluster data. If your Kubernetes cluster uses etcd as its backing store, make sure you have a back up plan for those data.

kube-scheduler:

Control plane component that watches for newly created Pods with no assigned node, and selects a node for them to run on. 

Factors taken into account for scheduling decisions include: individual and collective resource requirements, hardware/software/policy constraints, affinity and anti-affinity specifications, data locality, inter-workload interference, and deadlines.

kube-controller-manager:

Control plane component that runs controller processes. Logically, each controller is a separate process, but to reduce complexity, they are all compiled into a single binary and run in a single process.

Worker/Node components: 

Kubelet: 

An agent that runs on each node in the cluster. It makes sure that containers are running in a Pod.

The kubelet takes a set of PodSpecs that are provided through various mechanisms and ensures that the containers described in those PodSpecs are running and healthy. The kubelet doesn't manage containers which were not created by Kubernetes.

kube-proxy:

kube-proxy is a network proxy that runs on each node in your cluster, implementing part of the Kubernetes Service concept. kube-proxy maintains network rules on nodes. These network rules allow network communication to your Pods from network sessions inside or outside of your cluster.

kube-proxy uses the operating system packet filtering layer if there is one and it's available. Otherwise, kube-proxy forwards the traffic itself.

Container runtime:

The container runtime is the software that is responsible for running containers.