Building an HA k3s Control Plane on Ubuntu 24.04 LTS: Terraform, Ansible, kube-vip, and a Real Failover Drill

cw@wagner.org.za (Chrisando Wagner) — Tue, 28 Jul 2026 00:00:00 +0000

This is the latest iteration of my homelab automation: Terraform provisions six Ubuntu 24.04 LTS VMs on Proxmox, Ansible turns three of them into an HA k3s control plane with embedded etcd and a kube-vip floating VIP, and ArgoCD takes over GitOps management of everything above the OS the moment the cluster is up. It’s IaC end to end — nothing in this post was clicked into existence, and the two commands that matter (terraform apply, ansible-playbook site.yml) are the only manual steps in the whole build.

Homelab Part 4 - k3s Automation

cw@wagner.org.za (Chrisando Wagner) — Mon, 06 Apr 2026 00:00:00 +0000

In Part 3 we deployed k3s manually — great for understanding what each piece does, but not something you want to repeat. This post automates the entire thing: Terraform provisions the VMs, Ansible configures them and installs k3s + Cilium, and ArgoCD bootstraps itself and takes over GitOps management of the full cluster stack.

Source: git.wagner.org.za/homelab/k3s-proxmox-automation

Architecture
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┌──────────────────────────────────────────────────────────────────────────────┐
│ Proxmox Host │
│ │
│ ┌─────────────────┐ ┌───────────────┐ ┌───────────────┐ ┌────────────┐ │
│ │ k3s-controller │ │ k3s-worker-01 │ │ k3s-worker-02 │ │k3s-worker │ │
│ │ 172.16.10.1 │ │ 172.16.10.2 │ │ 172.16.10.3 │ │172.16.10.4 │ │
│ │ 8 cores / 16 GB │ │ 16c / 32 GB │ │ 16c / 32 GB │ │16c / 32 GB │ │
│ │ vda: 200 GB │ │ vda: 200 GB │ │ vda: 200 GB │ │vda: 200 GB │ │
│ │ │ │ vdb: 512 GB │ │ vdb: 512 GB │ │vdb: 512 GB │ │
│ │ k3s server │ │ vdc: 512 GB │ │ vdc: 512 GB │ │vdc: 512 GB │ │
│ │ Cilium / ArgoCD │ │ k3s agent │ │ k3s agent │ │k3s agent │ │
│ └────────┬────────┘ └──────┬────────┘ └──────┬────────┘ └─────┬──────┘ │
│ └───────────────-──┴──────────────────┴────────────-────┘ │
└──────────────────────────────────────────────────────────────────────────────┘

graph TB subgraph Proxmox["Proxmox Host"] C["k3s-controller-01
172.16.10.1
8c / 16 GB
vda: 200 GB OS
─────────────
k3s server
Cilium · ArgoCD"] W1["k3s-worker-01
172.16.10.2
16c / 32 GB
vda: 200 GB OS
vdb: 512 GB DirectPV
vdc: 512 GB Longhorn
─────────────
k3s agent"] W2["k3s-worker-02
172.16.10.3
16c / 32 GB
vda: 200 GB OS
vdb: 512 GB DirectPV
vdc: 512 GB Longhorn
─────────────
k3s agent"] W3["k3s-worker-03
172.16.10.4
16c / 32 GB
vda: 200 GB OS
vdb: 512 GB DirectPV
vdc: 512 GB Longhorn
─────────────
k3s agent"] end C -->|k3s API :6443| W1 C -->|k3s API :6443| W2 C -->|k3s API :6443| W3 C & W1 & W2 & W3 -->|eBGP AS 65000| R["Router
172.16.10.254"] R -->|advertises LB pool
172.16.1.0/24| NET["Network"]

Each worker gets three disks:

Terraform on Chris Wagner

Building an HA k3s Control Plane on Ubuntu 24.04 LTS: Terraform, Ansible, kube-vip, and a Real Failover Drill

Homelab Part 4 - k3s Automation

Architecture #

Architecture
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