# k3sup — Bootstrap K3s Clusters Over SSH in Under a Minute

> k3sup (ketchup) is a lightweight CLI that installs K3s on any remote server over SSH with a single command, enabling fast Kubernetes cluster creation on bare metal, VMs, or Raspberry Pis without complex setup scripts.

## Install

Save as a script file and run:

# k3sup — Bootstrap K3s Clusters Over SSH in Under a Minute

## Quick Use
```bash
# Install k3sup
curl -sLS https://get.k3sup.dev | sh
sudo install k3sup /usr/local/bin/
# Install K3s server on a remote host
k3sup install --ip 192.168.1.10 --user ubuntu
# Join a worker node
k3sup join --ip 192.168.1.11 --server-ip 192.168.1.10 --user ubuntu
# Kubeconfig is saved locally, ready to use
export KUBECONFIG=$(pwd)/kubeconfig
kubectl get nodes
```

## Introduction
k3sup simplifies Kubernetes cluster bootstrapping by wrapping K3s installation into a single command that works over SSH. It removes the need for Ansible playbooks or manual shell scripts when setting up lightweight Kubernetes clusters.

## What k3sup Does
- Installs a K3s server on any Linux host over SSH with one command
- Joins additional worker nodes to an existing cluster with automatic token exchange
- Fetches the kubeconfig file and merges it locally for immediate kubectl access
- Supports multi-master HA setups with embedded etcd or external datastore
- Installs Helm charts and Kubernetes apps via the built-in app catalog

## Architecture Overview
k3sup is a single Go binary that SSH-es into target machines, downloads the K3s installer, runs it with the correct flags, and retrieves the resulting kubeconfig. It does not install an agent or leave a daemon on the target; all orchestration happens client-side. The optional `k3sup app install` feature uses Helm under the hood.

## Self-Hosting & Configuration
- No server-side installation needed; k3sup runs entirely from your local machine
- Requires SSH key-based access to target hosts (password auth also supported)
- K3s version can be pinned with `--k3s-version` for reproducible deployments
- Custom K3s flags are passed through with `--k3s-extra-args` for TLS SANs, disable components, etc.
- Works on x86_64, ARM64, and ARMv7 for Raspberry Pi clusters

## Key Features
- Single binary with zero dependencies beyond SSH access to the target
- Full cluster from zero to kubectl-ready in under 60 seconds
- Built-in app installer for cert-manager, OpenFaaS, Prometheus, and other popular tools
- HA mode with `--cluster` flag for multi-server etcd-based setups
- Cross-architecture support makes it ideal for edge and IoT Kubernetes deployments

## Comparison with Similar Tools
- **k3s installer script** — The raw script requires manual token passing and kubeconfig retrieval; k3sup automates the full flow
- **Ansible + K3s** — Ansible playbooks are flexible but heavyweight; k3sup is a single binary with no inventory files
- **kubeadm** — Official bootstrapper for full K8s; k3sup targets lightweight K3s clusters with less ceremony
- **Rancher** — Full management platform with a web UI; k3sup is CLI-only and focused purely on bootstrapping
- **Talos Linux** — Immutable K8s OS; k3sup works on any existing Linux distribution

## FAQ
**Q: Does k3sup work with Raspberry Pi?**
A: Yes. k3sup fully supports ARM architectures and is widely used for Pi-based home clusters.

**Q: Can I install additional software after cluster creation?**
A: Yes. The `k3sup app install` command provides a curated catalog of Helm-based apps for common cluster add-ons.

**Q: Does k3sup support HA clusters?**
A: Yes. Use `--cluster` on the first server and `--server --server-ip` for additional control plane nodes with embedded etcd.

**Q: Is k3sup suitable for production?**
A: It is a bootstrapping tool. The resulting K3s cluster is production-ready (K3s is CNCF-certified); k3sup simply automates the setup.

## Sources
- https://github.com/alexellis/k3sup
- https://k3sup.dev/

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Source: https://tokrepo.com/en/workflows/92f4758c-39c9-11f1-9bc6-00163e2b0d79
Author: Script Depot