k0s - Zero Friction Kubernetes

k0s is an all-inclusive Kubernetes distribution with all the required bells and whistles preconfigured to make building a Kubernetes clusters a matter of just copying an executable to every host and running it.

Key Features

• Packaged as a single static binary
• Self-hosted, isolated control plane
• Variety of storage backends: etcd, SQLite, MySQL (or any compatible), PostgreSQL
• Elastic control-plane
• Vanilla upstream Kubernetes
• Supports custom container runtimes (containerd is the default)
• Supports custom Container Network Interface (CNI) plugins (kube-router is the default)
• Supports x86-64, ARM64 and ARMv7

Try k0s

If you'd like to try k0s, please jump to our:

• Quick Start Guide - Create a full Kubernetes cluster with a single node that includes both the controller and the worker.
• Install using k0sctl - Deploy and upgrade multi-node clusters with one command.
• NanoDemo - Watch a .gif recording of how to create a k0s instance.
• Run k0s in Docker - Run k0s controllers and workers in containers.
• For docs, tutorials, and other k0s resources, see docs main page.

Join the Community

If you'd like to help build k0s, please check out our guide to Contributing and our Code of Conduct.

Motivation

We have seen a gap between the host OS and Kubernetes that runs on top of it: How to ensure they work together as they are upgraded independent from each other? Who’s responsible for vulnerabilities or performance issues originating from the host OS that affect the K8S on top?

→ k0s is fully self contained. It’s distributed as a single binary with no host OS deps besides the kernel. Any vulnerability or perf issues may be fixed in k0s Kubernetes.

We have seen K8S with partial FIPS security compliance: How to ensure security compliance for critical applications if only part of the system is FIPS compliant?

→ k0s core + all included host OS dependencies + components on top may be compiled and packaged as a 100% FIPS compliant distribution using a proper toolchain.

We have seen Kubernetes with cumbersome lifecycle management, high minimum system requirements, weird host OS and infra restrictions, and/or need to use different distros to meet different use cases.

→ k0s is designed to be lightweight at its core. It comes with a tool to automate cluster lifecycle management. It works on any host OS and infrastructure, and may be extended to work with any use cases such as edge, IoT, telco, public clouds, private data centers, and hybrid & hyper converged cloud applications without sacrificing the pure Kubernetes compliance or amazing developer experience.

Other Features

• Kubernetes 1.20, 1.21
• Container Runtime:
  • ContainerD (default)
  • Custom (bring-your-own)
• Control plane storage options:
  • etcd (default for multi-node clusters)
  • sqlite (default for single node clusters)
  • PostgreSQL (external)
  • MySQL (external)
• CNI providers
  • Kube-Router (default)
  • Calico
  • Custom (bring-your-own)
• Control plane isolation:
  • Fully isolated (default)
  • Tainted worker
• Control plane - node communication
  • Konnectivity service (default)
• CoreDNS
• Metrics-server

Status

k0s is ready for production (starting from v1.21.0+k0s.0). Since the initial release of k0s back in November 2020, we have made numerous releases, improved stability, added new features, and most importantly, listened to our users and community in an effort to create the most modern Kubernetes product out there. The active development continues to make k0s even better.

Scope

While some Kubernetes distros package everything and the kitchen sink, k0s tries to minimize the amount of "add-ons" to bundle in. Instead, we aim to provide a robust and versatile "base" for running Kubernetes in various setups. Of course we will provide some ways to easily control and setup various "add-ons", but we will not bundle many of those into k0s itself. There are a couple of reasons why we think this is the correct way:

• Many of the addons such as ingresses, service meshes, storage etc. are VERY opinionated. We try to build this base with less opinions. :D
• Keeping up with the upstream releases with many external addons is very maintenance heavy. Shipping with old versions does not make much sense either.

With strong enough arguments we might take in new addons, but in general those should be something that are essential for the "core" of k0s.

Build

k0s can be built in 3 different ways:

Fetch official binaries (except konnectivity-server, which are built from source):

make EMBEDDED_BINS_BUILDMODE=fetch

Build Kubernetes components from source as static binaries (requires docker):

make EMBEDDED_BINS_BUILDMODE=docker

Build k0s without any embedded binaries (requires that Kubernetes binaries are pre-installed on the runtime system):

make EMBEDDED_BINS_BUILDMODE=none

Builds can be done in parallel:

make -j$(nproc)

Smoke test

To run a smoke test after build:

make check-basic