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Download the k0s binary#

Prerequisites#

Before proceeding, make sure to review the System Requirements

K0s Download Script#

$ curl -sSLf https://get.k0s.sh | sudo sh
The download script accepts the following environment variables:

  1. K0S_VERSION=v0.11.0 - select the version of k0s to be installed
  2. DEBUG=true - outputs commands and their arguments as they are executed.

Installing k0s as a service on the local system#

The k0s install sub-command will install k0s as a system service on hosts running one of the supported init systems: Systemd or OpenRC.

Install can be executed for workers, controllers or single node (controller+worker) instances.

The install controller sub-command accepts the same flags and parameters as the k0s controller sub-command does.

$ k0s install controller --help

Helper command for setting up k0s as controller node on a brand-new system. Must be run as root (or with sudo)

Usage:
  k0s install controller [flags]

Aliases:
  controller, server

Examples:
All default values of controller command will be passed to the service stub unless overriden. 

With controller subcommand you can setup a single node cluster by running:

        k0s install controller --enable-worker


Flags:
  -c, --config string            config file (default: ./k0s.yaml)
      --cri-socket string        contrainer runtime socket to use, default to internal containerd. Format: [remote|docker]:[path-to-socket]
  -d, --debug                    Debug logging (default: false)
      --enable-worker            enable worker (default false)
  -h, --help                     help for controller
  -l, --logging stringToString   Logging Levels for the different components (default [konnectivity-server=1,kube-apiserver=1,kube-controller-manager=1,kube-scheduler=1,kubelet=1,kube-proxy=1,etcd=info,containerd=info])
      --profile string           worker profile to use on the node (default "default")
      --token-file string        Path to the file containing join-token.

Global Flags:
      --data-dir string        Data Directory for k0s (default: /var/lib/k0s). DO NOT CHANGE for an existing setup, things will break!
      --debugListenOn string   Http listenOn for debug pprof handler (default ":6060")

For example, the command below will install a single node k0s service on Ubuntu 20.10:

$ k0s install controller --enable-worker
INFO[2021-02-24 11:05:42] no config file given, using defaults         
INFO[2021-02-24 11:05:42] creating user: etcd                          
INFO[2021-02-24 11:05:42] creating user: kube-apiserver                
INFO[2021-02-24 11:05:42] creating user: konnectivity-server           
INFO[2021-02-24 11:05:42] creating user: kube-scheduler                
INFO[2021-02-24 11:05:42] Installing k0s service

Run k0s as a service#

$ systemctl start k0scontroller

Check service status#

$ systemctl status k0scontroller
     Loaded: loaded (/etc/systemd/system/k0scontroller.service; enabled; vendor preset: enabled)
     Active: active (running) since Fri 2021-02-26 08:37:23 UTC; 1min 25s ago
       Docs: https://docs.k0sproject.io
   Main PID: 1408647 (k0s)
      Tasks: 96
     Memory: 1.2G
     CGroup: /system.slice/k0scontroller.service
     ....

Query cluster status#

$ k0s status
Version: v0.11.0-beta.2-16-g02cddab
Process ID: 9322
Parent Process ID: 1
Role: controller+worker
Init System: linux-systemd

Fetch nodes#

$ k0s kubectl get nodes
NAME   STATUS   ROLES    AGE    VERSION
k0s    Ready    <none>   4m6s   v1.20.4-k0s1

Enabling Shell Completion#

The k0s completion script for Bash, zsh, fish and powershell can be generated with the command k0s completion < shell >. Sourcing the completion script in your shell enables k0s autocompletion.

Bash#

echo 'source <(k0s completion bash)' >>~/.bashrc

# To load completions for each session, execute once:
$ k0s completion bash > /etc/bash_completion.d/k0s

Zsh#

If shell completion is not already enabled in your environment you will need to enable it. You can execute the following once: 

$ echo "autoload -U compinit; compinit" >> ~/.zshrc

# To load completions for each session, execute once:
$ k0s completion zsh > "${fpath[1]}/_k0s"
You will need to start a new shell for this setup to take effect.

Fish#

$ k0s completion fish | source

# To load completions for each session, execute once:
$ k0s completion fish > ~/.config/fish/completions/k0s.fish

Under the hood#

Workers are always run as root. For controllers, the command will create the following system users: etcd, kube-apiserver, konnectivity-server, kube-scheduler

Additional Documentation#

see: k0s install