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Lightweight Kubernetes. Easy to install, half the memory, all in a binary of less than 100 MB.

Great for:

  • Edge
  • Homelab
  • Internet of Things (IoT)
  • Continuous Integration (CI)
  • Development
  • Single board computers (ARM)
  • Air-gapped environments
  • Embedded K8s
  • Situations where a PhD in K8s clusterology is infeasible

What is K3s?

K3s is a fully compliant Kubernetes distribution with the following enhancements:

  • Distributed as a single binary or minimal container image.
  • Lightweight datastore based on sqlite3 as the default storage backend. etcd3, MySQL, and Postgres are also available.
  • Wrapped in simple launcher that handles a lot of the complexity of TLS and options.
  • Secure by default with reasonable defaults for lightweight environments.
  • Operation of all Kubernetes control plane components is encapsulated in a single binary and process, allowing K3s to automate and manage complex cluster operations like distributing certificates.
  • External dependencies have been minimized; the only requirements are a modern kernel and cgroup mounts.
  • Packages the required dependencies for easy "batteries-included" cluster creation:
    • containerd / cri-dockerd container runtime (CRI)
    • Flannel Container Network Interface (CNI)
    • CoreDNS Cluster DNS
    • Traefik Ingress controller
    • ServiceLB Load-Balancer controller
    • Kube-router Network Policy controller
    • Local-path-provisioner Persistent Volume controller
    • Spegel distributed container image registry mirror
    • Host utilities (iptables, socat, etc)

What's with the name?

We wanted an installation of Kubernetes that was half the size in terms of memory footprint. Kubernetes is a 10-letter word stylized as K8s. So something half as big as Kubernetes would be a 5-letter word stylized as K3s. There is no long form of K3s and no official pronunciation.