Kubernetes

Kubernetes, often abbreviated as K8s (where 8 represents the eight letters between "K" and "s"), is an open-source container orchestration platform developed by Google. It is designed to automate the deployment, scaling, and management of containerized applications. Containers are a lightweight and portable way to package and distribute applications, along with their dependencies and configuration, ensuring consistency across various environments.


Kubernetes provides a framework to manage clusters of containers, making it easier for developers to deploy and manage applications, as well as enabling efficient resource utilization in a dynamic and scalable manner. Some key features of Kubernetes include:

Container Orchestration: Kubernetes can schedule containers onto available nodes in the cluster, ensuring that the right number of replicas are running and maintaining the desired state of applications.


Automatic Scaling: Kubernetes can automatically scale the number of container replicas based on defined rules or metrics. This allows applications to handle varying workloads efficiently.


Self-healing: Kubernetes monitors the health of containers and can automatically restart or replace failed containers to maintain application availability.


Service Discovery and Load Balancing: Kubernetes provides internal DNS for service discovery, allowing containers to communicate with each other using service names. It also distributes incoming network traffic to the containers through built-in load balancing mechanisms.


Config and Secret Management: Kubernetes provides a way to manage configuration data and sensitive information (such as passwords) through ConfigMaps and Secrets, respectively.


Rollouts and Rollbacks: Kubernetes enables smooth updates of applications by managing rolling updates and rollbacks to previous versions.


Resource Management: Kubernetes allows you to set resource limits and requests for containers, ensuring fair sharing of resources and preventing one container from monopolizing the cluster.

Kubernetes has become the de facto standard for container orchestration due to its robustness, scalability, and active community support. It abstracts away the complexities of managing individual containers and helps developers focus on building applications while ensuring reliability, scalability, and flexibility in production environments.




Components of Kubernetes


ChatGPT



Kubernetes is composed of several core components that work together to provide its container orchestration capabilities. These components interact with each other to manage and maintain the desired state of the cluster and the applications running on it. Here are the main components of Kubernetes:

Master Node:API Server: The central control point for the Kubernetes cluster. It exposes the Kubernetes API and handles all the requests to the cluster.
etcd: A distributed key-value store that stores the cluster's configuration data, including the desired state of the resources.
Scheduler: Responsible for scheduling the containers onto nodes based on resource availability, constraints, and other policies.
Controller Manager: Manages various controllers that handle the cluster's state, such as replication controller, node controller, endpoint controller, and more.


Worker Node (Minion):Kubelet: The agent running on each node, responsible for communicating with the API server and ensuring containers are running as expected on the node.
Container Runtime: The software responsible for running containers, such as Docker or containerd.
Kube-proxy: Handles network proxying and load balancing for services running on the node.


Networking:Container Network Interface (CNI): A specification that allows various networking plugins to be used with Kubernetes for container networking.
Pod Network: A network overlay that facilitates communication between pods across different nodes in the cluster.


Add-ons:DNS Add-on: Provides DNS-based service discovery within the cluster.
Dashboard: A web-based user interface for managing and monitoring the cluster.
Ingress Controller: Manages external access to services within the cluster.
Heapster (now replaced by Metrics Server): Collects and exposes cluster resource metrics and usage.

These components collaborate to ensure that containers are deployed and managed effectively across the cluster. The master node controls and monitors the cluster's overall state, while the worker nodes host the containers and run them in accordance with the desired configuration set by the user. Kubernetes also allows for extensibility through custom resources and controllers, enabling users to define their own object types and automate custom operations on those objects.