What is K3s?

Description

K3s is a lightweight version of Kubernetes. It’s production ready, easy to install, half the memory, all in a binary less than 100 MB.^[1]

K3s is a fully compliant Kubernetes distribution with the following enhancements:^[2]

• Packaged as a single binary.
• Lightweight storage backend based on sqlite3 as the default storage mechanism. etcd3, MySQL, Postgres also still 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.
• Simple but powerful “batteries-included” features have been added, such as: a local storage provider, a service load balancer, a Helm controller, and the Traefik ingress controller.
• Operation of all Kubernetes control plane components is encapsulated in a single binary and process. This allows K3s to automate and manage complex cluster operations like distributing certificates.
• External dependencies have been minimized (just a modern kernel and cgroup mounts needed). K3s packages required dependencies, including:
  • containerd
  • Flannel
  • CoreDNS
  • CNI
  • Host utilities (iptables, socat, etc)
  • Ingress controller (traefik)
  • Embedded service loadbalancer
  • Embedded network policy controller

Use Cases

K3s is great for. . .

• Edge
• IoT
• CI
• Development
• ARM
• Embedding K8s
• Situations where a PhD in k8s clusterology is infeasible^[1:1]

K3s can provide similar capabilities to EVE through other CNCF and cloud native projects, and, when built as part of a complete architecture, can resemble a complete system more like EdgeX Foundry.^[3]

Perfect for Edge

K3s is highly available and designed for production workloads in unattended, resource-constrained, remote locations or inside IoT appliances.^[4]

Simplified & Secure

K3s is packaged as a single <50MB binary that reduces the dependencies and steps needed to install, run and auto-update a production Kubernetes cluster.^[4:1]

Optimized for ARM

Both ARM64 and ARMv7 are supported with binaries and multiarch images available for both. K3s works great from something as small as a Raspberry Pi to an AWS a1.4xlarge 32GiB server.^[4:2]

Background

K3s is an open source project.^[1:2] It was originally developed by Rancher Labs, a market leader in Kubernetes management software.^[2:1]

In August 2020, Rancher Labs donated K3s to the Cloud Native Computing Foundation (CNCF) who officially added K3s as a sandbox-level project managed under the auspices of the open source consortium. This action helped to ensure that open source governance policies would be applied in a way that does not unduly influence future product decisions in favor of any one vendor.^[5]

SUSE, the German-based multinational open-source software company, acquired Rancher Labs in December of 2020.^[6]