Building a K3s cluster on Proxmox

Setting up a k3s cluster on Proxmox requires three VMs, an external load balancer, and a shared NFS mount for persistent storage. This article describes the exact steps for a production-ready setup.

Why use k3s on Proxmox?

K3s runs perfectly well on lightweight VMs. On Proxmox, I allocate 2 vCPUs and 2GB of RAM to each node — more than enough for a home lab cluster. The big advantage over full K8s is the installation: just one command per node.

Node setup

Three Ubuntu 24.04 VMs: k3s-1 as the control plane, k3s-2 and k3s-3 as workers.

# Control plane
curl -sfL https://get.k3s.io | sh -s - server \
  --disable traefik \
  --tls-san k3s.siekman.io

# Retrieve token
cat /var/lib/rancher/k3s/server/node-token

# Workers (replace TOKEN and SERVER_IP)
curl -sfL https://get.k3s.io | K3S_URL=https://SERVER_IP:6443 \
  K3S_TOKEN=TOKEN sh -

External Nginx reverse proxy

I’m deliberately disabling Traefik — I’m using an existing Nginx instance outside the cluster as the ingress point.

upstream k3s_nodes {
    server 192.168.1.11:80;
    server 192.168.1.12:80;
    server 192.168.1.13:80;
}

server {
    listen 443 ssl;
    server_name *.siekman.io;
    location / {
    proxy_pass http://k3s_nodes;
    }
}

NFS for persistent storage

# On the NFS server
apt install nfs-kernel-server
echo "/mnt/k3s-data 192.168.1.0/24(rw,sync,no_subtree_check)" >> /etc/exports
exportfs -ra

This provides you with a stable foundation for stateful workloads such as MariaDB and Gitea.