K3S Single-Node Installation

Requirements #

Linux host with 1 CPU / 512 MB RAM minimum (2 CPU / 2 GB recommended)
Ports open between nodes: 6443/tcp (API), 8472/udp (flannel VXLAN), 10250/tcp (kubelet)
Hostname unique per node

bash

curl -sfL https://get.k3s.io | sh -

Pin a version:

bash
curl -sfL https://get.k3s.io | INSTALL_K3S_VERSION=v1.31.4+k3s1 sh -

Disable the bundled Traefik or ServiceLB if you bring your own:

bash
curl -sfL https://get.k3s.io | INSTALL_K3S_EXEC="--disable traefik --disable servicelb" sh -

bash

sudo systemctl status k3s
sudo k3s kubectl get nodes

bash
mkdir -p ~/.kube
sudo cp /etc/rancher/k3s/k3s.yaml ~/.kube/config
sudo chown "$USER": ~/.kube/config
chmod 600 ~/.kube/config

To use it from another machine, copy the file and replace 127.0.0.1 in server: with the server’s IP or DNS name.

Get the token on the server:

bash

sudo cat /var/lib/rancher/k3s/server/node-token

Run on the worker:

bash
curl -sfL https://get.k3s.io | K3S_URL=https://<SERVER-IP>:6443 K3S_TOKEN=<TOKEN> sh -

PATH	DESCRIPTION
`/etc/rancher/k3s/k3s.yaml`	Kubeconfig
`/etc/rancher/k3s/config.yaml`	Server config (flags as YAML keys)
`/var/lib/rancher/k3s/server/manifests/`	Manifests here are auto-applied
`/var/lib/rancher/k3s/server/node-token`	Join token
`/var/lib/rancher/k3s/server/db/`	SQLite datastore (single node)

COMMAND	DESCRIPTION
`sudo journalctl -u k3s -f`	Server logs
`sudo k3s etcd-snapshot save`	Snapshot (embedded etcd only)
`sudo systemctl restart k3s`	Restart
`/usr/local/bin/k3s-killall.sh`	Stop all K3s processes and containers
`/usr/local/bin/k3s-uninstall.sh`	Uninstall server
`/usr/local/bin/k3s-agent-uninstall.sh`	Uninstall agent

Re-run the install script with a newer INSTALL_K3S_VERSION (or none for latest stable). For clusters, use the system-upgrade-controller.