Overview of Kubernetes architecture

Category : Kubernetes | Sub Category : Learn Kubernetes | By Prasad Bonam Last updated: 2023-11-22 06:58:20 Viewed : 222

Overview of Kubernetes architecture:

Kubernetes is an open-source container orchestration platform that automates the deployment, scaling, and management of containerized applications. Its architecture is designed to provide a flexible and extensible platform for running containers at scale. Here is an overview of the key components and concepts in Kubernetes architecture:

1. Master Node:

   • API Server: Acts as the control plane that exposes the Kubernetes API. All administrative tasks and communication with the cluster are done through the API server.
   • Controller Manager: Manages various controllers that regulate the state of the system. Examples include the Node Controller, Replication Controller, and Endpoints Controller.
   • Scheduler: Assigns newly created pods to nodes based on resource availability, policies, and other constraints.

2. Node (Minion) / Worker Node:

   • Kubelet: Responsible for maintaining the set of containers on a node. It ensures that containers are running in a Pod.
   • Container Runtime: The software responsible for running containers, such as Docker or containerd.
   • Kube Proxy: Maintains network rules on the host and performs connection forwarding.

3. Pod:

   • The smallest and simplest unit in the Kubernetes object model.
   • A pod represents a single instance of a running process in a cluster and may contain one or more containers.

4. Controller:

   • Ensures the desired state of the system. Examples include ReplicaSet, Deployment, and StatefulSet controllers.
   • Controllers continuously work to reconcile the current state with the desired state defined in the Kubernetes API.

5. Service:

   • Defines a logical set of pods and a policy by which to access them.
   • Services enable a group of pods to work together, providing a stable endpoint to access the application.

6. Volume:

   • Provides persistent storage to pods.
   • Volumes exist independently of the pod and persist beyond the life of the pod.

7. Namespace:

   • Provides a way to divide cluster resources between multiple users or teams.
   • Resources within a namespace can have the same name without conflicting.

8. Label:

   • Key/value pairs that are attached to objects, such as pods.
   • Labels are used for identification, grouping, and selection of objects.

9. Annotation:

   • Similar to labels, but they are not used to identify and select objects.
   • Annotations are for adding non-identifying metadata to objects.

Understanding these components and their interactions is crucial for effectively deploying and managing applications on a Kubernetes cluster. The architecture allows for scalability, resilience, and ease of management in a containerized environment.