Kubernetes Architecture

---

Kubernetes architecture is a hierarchical structure that consists of various components and layers, each with specific responsibilities and functionalities.

These components work together to manage and orchestrate containerized applications efficiently.

Key architectural components of Kubernetes:

1. Master Node:

   • API Server: The central control plane component that exposes the Kubernetes API, which users, command-line tools, and other Kubernetes components interact with. It validates and processes requests, and then communicates with other components to perform actions on the cluster.

   • etcd: A distributed and consistent key-value store that stores all cluster data, including configuration data and the current state of the cluster. It serves as the source of truth for the cluster and is used for maintaining cluster state and configuration.

   • Controller Manager: A set of controller processes that manage different aspects of the cluster's desired state. For example, the ReplicaSet Controller ensures that the correct number of pod replicas are running.

   • Scheduler: Responsible for assigning pods to worker nodes based on resource requirements, quality of service, and other constraints. It aims to optimize resource utilization and maintain high availability.

2. Worker Nodes:

   • Kubelet: An agent running on each worker node that communicates with the master node. It ensures that containers are running in a Pod, monitors their health, and reports the node's status to the master.

   • Container Runtime: The software responsible for running containers, such as Docker or containerd. Kubernetes supports various container runtimes, making it flexible in terms of container technology.

   • Kube Proxy: Maintains network rules on nodes. It performs network address translation (NAT) for service exposure and load balancing. Kube Proxy ensures that traffic to services is routed correctly to the appropriate pods.

   • Pod: The smallest deployable unit in Kubernetes. A pod can contain one or more containers that share the same network namespace, IP address, and storage volumes. Containers within the same pod can communicate with each other via localhost.

3. Add-Ons and Services:

   • DNS Server: Provides DNS-based service discovery and resolution within the cluster, allowing pods to communicate with each other using service names.

   • Dashboard: A web-based user interface for visualizing and managing the cluster. It provides a graphical representation of cluster resources and their status.

   • Ingress Controller: Manages external access to services within the cluster. It allows for the routing of incoming traffic to the appropriate services based on rules and configuration.

   • Logging and Monitoring: Kubernetes integrates with various logging and monitoring solutions like Prometheus, Grafana, and Elasticsearch/Fluentd/Kibana (EFK) to help monitor the cluster and applications.

4. Networking:

   • Kubernetes uses a networking model that enables pods on different nodes to communicate with each other. Network plugins, like Calico, Flannel, and Cilium, provide the necessary network overlay to facilitate pod-to-pod communication.

5. Storage:

   • Kubernetes offers various storage options, including Persistent Volumes (PVs) and Persistent Volume Claims (PVCs), for providing persistent storage to pods.

6. Security:

   • Kubernetes provides features for securing the cluster, including Role-Based Access Control (RBAC), Pod Security Policies (PSPs), and network policies. These help control access and enforce security policies.

7. Custom Resources and Operators:

   • Kubernetes allows users to define custom resources (CRs) and operators to extend the platform's capabilities. Operators automate the management of custom resources.

The interaction and coordination between these components enable Kubernetes to manage containerized workloads efficiently, providing features like auto-scaling, rolling updates, and self-healing for applications.

Kubernetes architecture is designed to be highly scalable, fault-tolerant, and extensible, making it suitable for a wide range of applications and infrastructure environments.

Enroll Now

• DevOps
• Kubernetes