Kubernetes architecture with key components

Kubernetes is a container orchestration platform that automates the deployment, scaling, and management of containerized applications. It comprises several components that work together to provide a robust and scalable container orchestration environment. Here are key Kubernetes components:

1. Master Components:

   • API Server:

     • Acts as the front end for the Kubernetes control plane.
     • Exposes the Kubernetes API and processes RESTful API requests.

   • etcd:

     • Consistent and highly-available key-value store used as Kubernetes’ backing store for all cluster data.

   • Controller Manager:

     • Runs controller processes that regulate the state of the system.
     • Examples include Node Controller, Replication Controller, and Endpoints Controller.

   • Scheduler:

     • Watches for newly created Pods with no assigned node and selects a node for them to run on.
     • Considers factors like resource requirements, affinity/anti-affinity, and more.

2. Node Components:

   • Kubelet:

     • An agent that runs on each node in the cluster.
     • Ensures that containers are running in a Pod.

   • Kube-Proxy:

     • Maintains network rules on nodes.
     • Enables communication to and from Pods.

   • Container Runtime:

     • Software responsible for running containers.
     • Common runtimes include Docker and containerd.

3. Controller Plane:

   • Refers to the combination of API Server, etcd, Controller Manager, and Scheduler.

4. Add-ons:

   • Additional components and services that add functionality to a Kubernetes cluster.

   • DNS:

     • Provides DNS-based service discovery.
     • Allows Pods to communicate with each other using names.

   • Dashboard:

     • Web-based user interface for managing and monitoring Kubernetes clusters.

   • Ingress Controller:

     • Manages external access to services in a cluster.
     • Configures external access rules based on Ingress resources.

   • Metrics-Server:

     • Exposes resource usage metrics for nodes and pods.

   • Kube-DNS (CoreDNS in newer versions):

     • Provides DNS-based service discovery in Kubernetes clusters.

   • Container Network Interface (CNI):

     • Specifies a standardized interface between container runtimes and network plugins.

These components work together to provide the necessary functionality for deploying, managing, and scaling containerized applications in a Kubernetes cluster. Each component plays a specific role in maintaining the desired state of the cluster and ensuring the smooth operation of containerized workloads.