Introduction to Kubernetes (K8s)
Kubernetes (often abbreviated as K8s) is an open-source container orchestration platform originally developed by Google. It is designed to automate the deployment, scaling, and management of containerized applications across distributed clusters of nodes.
Key Benefits of Kubernetes
✅ Zero Downtime Deployments – Ensures high availability with rolling updates and self-healing capabilities.
✅ Scalability – Automatically scales applications based on demand.
✅ Portability – Runs seamlessly across on-premises, cloud, and hybrid environments.
✅ Efficient Resource Utilization – Optimizes CPU and memory usage across clusters.
What Does Container Orchestration Do?
Kubernetes simplifies the management of microservices and containers by handling:
Configuring and Scheduling of Containers – Automates where and when containers run.
Provisioning and Deployment of Containers – Ensures seamless container deployment across clusters.
High Availability (HA) of Containers – Maintains uptime with failover and redundancy.
Load Balancing, Traffic Routing & Service Discovery – Distributes network traffic efficiently.
Health Monitoring of Containers – Continuously checks container status and restarts failed instances.
Securing Interactions Between Containers – Enforces network policies and secure communication.
Kubernetes Components & Architecture
K8s follows a master-worker architecture, where the control plane (master node) manages worker nodes that run the actual applications.
1. K8s Master Node (Control Plane)
The master node is the brain of Kubernetes, responsible for managing, scheduling, and monitoring the cluster.
1.1 Master Node Components
🔹 API Server
- Acts as the gateway to the Kubernetes cluster.
- Handles RESTful API requests for scaling, updates, and cluster operations.
🔹 Controller Manager
- The core control loop that manages different controllers.
- Ensures the cluster’s desired state (e.g., pod creation, node monitoring).
🔹 Replication Controller
- Ensures a specific number of pod replicas are always running.
- Maintains high availability by auto-replacing failed pods.
🔹 Node Controller
- Manages worker node lifecycle (addition, removal, health checks).
🔹 Scheduler
- Assigns pods to optimal worker nodes based on resource availability.
🔹 etcd Cluster
- A distributed key-value store that holds the entire cluster state.
- Stores configurations, node details, and cluster metadata.
2. Worker Nodes (Data Plane)
Worker nodes are servers that host and run containerized applications as pods.
2.1 Worker Node Components
🔹 Kubelet
- The primary agent running on each worker node.
- Ensures containers are healthy and running in the desired state.
- Reports node health back to the master.
🔹 Kube-Proxy
- Manages network rules on worker nodes.
- Enables service discovery and load balancing for pods.
Final Thoughts
Kubernetes is the gold standard for managing containerized applications at scale. Whether you're running microservices, CI/CD pipelines, or AI workloads, K8s provides the automation, resilience, and efficiency needed for modern cloud-native applications.
