How does kubernetes work?

How does Kubernetes work? Kubernetes is an open-source container orchestration platform that automates the deployment, scaling, and management of containerized applications. It provides a robust and scalable infrastructure to run and manage container-based workloads. Here’s an overview of how does Kubernetes work:

How Does Kubernetes Work?

1. Master-Worker Architecture: Kubernetes follows a master-worker architecture. The master node is responsible for managing and coordinating the cluster, while worker nodes, also known as minions, execute the actual workload.
2. Cluster Setup: To create a Kubernetes cluster, you typically start by setting up a master node and multiple worker nodes. The master node includes several key components:
   1. • API Server: It exposes the Kubernetes API, which allows clients to interact with the cluster and manage resources.
      • Scheduler: It assigns pods (the smallest deployable unit in Kubernetes) to available worker nodes based on resource requirements and constraints.
      • Controller Manager: It maintains the desired state of the cluster by managing various controllers that handle tasks such as scaling, replication, and self-healing.
      • etcd: It is a distributed key-value store used for storing cluster configuration and state.
3. Pods: A pod is the basic unit of deployment in Kubernetes. It represents a group of one or more containers deployed together on a single worker node. Containers within a pod share the same network namespace and can communicate with each other using localhost.
4. Replication and Scaling: Kubernetes supports scaling and replication of pods to ensure high availability and load balancing. Thus, you can define the desired number of replicas for a pod. And Kubernetes automatically manages their creation, distribution, and monitoring across the worker nodes.
5. Service Discovery and Load Balancing: Kubernetes provides a built-in service discovery mechanism that allows pods to discover each other using DNS or environment variables. Additionally, it provides load-balancing capabilities to distribute incoming traffic across pods.
6. Declarative Configuration: Kubernetes uses declarative configuration files, typically written in YAML or JSON, to define the desired state of the cluster and its resources. So, you specify the desired configuration, including pods, services, volumes, and more, in these files, and Kubernetes ensures the cluster matches that desired state.
7. Health Monitoring and Self-Healing: Kubernetes continuously monitors the health of pods and their associated containers. So, if a pod or container fails, then Kubernetes automatically restarts it or creates a new replacement instance to maintain the desired state.
8. Persistent Storage: Kubernetes supports various storage options, including Persistent Volumes (PV) and Persistent Volume Claims (PVC), to provide durable storage for applications. This allows data to persist even if pods are terminated or moved between nodes.
9. Networking: Kubernetes manages networking between pods within the cluster using an overlay network. So, each pod gets its IP address, and containers within the same pod communicate via the localhost interface. Kubernetes also supports network policies for fine-grained control over traffic between pods.
10. Extensibility and Ecosystem: Kubernetes has a rich ecosystem with a wide range of extensions, including custom resource definitions (CRDs), operators, and add-ons. These extensions provide additional functionalities, such as managing complex applications, automating tasks, and integrating with external services.

Using these core components and features, Kubernetes simplifies the management of containerized applications by making it easier to deploy, scale, and manage workloads in a distributed environment. Thus, it abstracts away the complexities of the underlying infrastructure, allowing developers and operators to focus on the logic and scalability of the application.