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Kubernetes

A container orchestration system for clusters.

Kubernetes schedules containers onto a cluster of machines, restarts them when they fail, scales them up and down with demand, exposes them through stable network identities and load-balanced services, and rolls out new versions while keeping the system available. Applications are described declaratively as YAML manifests, and the control plane works continuously to reconcile cluster state with that declaration.

The control plane consists of the API server (the front door for everything), etcd (the consistent state store), the scheduler (which decides where to place new Pods), and a controller manager (which runs the controllers that watch and reconcile state). Kubelets on each worker node run containers through containerd or another OCI runtime. The CRD (Custom Resource Definition) mechanism lets users extend Kubernetes itself with their own resource types and controllers.

Joe Beda, Brendan Burns, and Craig McLuckie started Kubernetes at Google in 2014 as an open-source successor to Google's internal Borg cluster manager. The Cloud Native Computing Foundation has governed the project since 2015. Kubernetes is now the foundation of most modern cloud-native infrastructure; AWS EKS, Google GKE, Azure AKS, IBM Cloud, Digital Ocean Kubernetes, and many other managed services run it.

For local development, install kind, minikube, or k3s:
  Linux:  curl -Lo ./kind https://kind.sigs.k8s.io/dl/v0.23.0/kind-linux-amd64 && chmod +x kind
  macOS:  brew install kind
For the kubectl CLI:
  Debian/Ubuntu: sudo apt install kubectl
  Fedora/RHEL:   sudo dnf install kubectl