Kubernetes Fundamentals: Orchestrating Containers at Scale

Kubernetes helps run containers across many machines. It schedules workloads, restarts failed apps, and coordinates updates so services stay available. This makes it easier for teams to deploy modern applications, whether they run in the cloud or on premises.

A cluster has two main parts: the control plane and the worker nodes. The control plane decides where to run tasks and tracks the desired state. The nodes actually run the containers, grouped into pods. Pods are the smallest deployable units and usually hold one container, but can host a few that share storage and network. Deployments manage the lifecycle of pods, while Services expose them inside the cluster or to users outside.

Key objects include Pod, Deployment, Service, ConfigMap, and Secret. Ingress handles external access, and PersistentVolume keeps data beyond pod restarts. The API server, etcd, and controllers form the control plane to keep things healthy and on track.

Networking and storage matter. Each pod receives a stable address inside the cluster, and Services provide stable endpoints for clients. Storage uses PersistentVolumes and PersistentVolumeClaims to preserve data across pod restarts.

Scaling and updates help teams grow safely. Horizontal Pod Autoscaler adjusts pod counts based on load. Deployments support rolling updates, pausing or rolling back if something goes wrong, and ensuring minimal downtime.

Resilience features improve reliability. Readiness probes ensure a pod is ready to serve traffic, while liveness probes can restart malfunctioning containers. Kubernetes automatically reschedules work on healthy nodes and load balances traffic via Services.

Observability and getting started. Use logs, metrics, and events to understand the system. Start with kubectl get pods and kubectl describe from a local cluster, then add dashboards and monitoring as you grow.

Getting started with a local setup is simple. Install minikube or kind, configure kubectl, and run a small app. Add ConfigMaps, Secrets, and a simple CI/CD flow to push updates automatically.

Example scenario. A web API runs three replicas. Each pod requests 100m CPU and 128Mi memory. A Service routes internal traffic, and an Ingress exposes the app. With a rolling update, updates stay smooth and safe.

Key Takeaways

  • Kubernetes automates container orchestration, helping scale and maintain apps.
  • Core objects to know are Pod, Deployment, Service, and Ingress for access.
  • Use autoscaling, readiness and liveness probes, and observability to run reliable clusters.