Pi Cluster Documentation
Pi Cluster Documentation

Quick Start Instructions

These are the instructions to quickly deploy Kubernetes Pi-cluster using the following tools:

  • cloud-init: to automate initial OS installation/configuration on each node of the cluster
  • Ansible: to automatically configure cluster nodes, and orchestrate the installation and configuration, via Terraform, of external services (DNS, DHCP, Firewall, S3 Storage server, Hashicorp Vault), K3S, and bootstrapping the cluster through installation and configuration of FluxCD
  • Terraform/OpenTofu: to configure external servies like Hashicorp Vault and MinIO S3 server.
  • Flux CD: to automatically deploy Applications to Kuberenetes cluster from manifest files in Git repository.

Ansible control node setup

  • Use your own Linux-based PC or set up an Ubuntu Server VM to become ansible control node (pimaster)

    In case of building a VM check out tip for automating its creation in “Ansible Control Node”.

  • Clone Pi-Cluster Git repo or download using the ‘Download ZIP’ link on GitHub.

    git clone https://github.com/ricsanfre/pi-cluster.git

  • Install docker and docker compose

    Follow instructions in “Ansible Control Node: Installing Ansible Runtime environment”.

  • Create and configure Ansible execution environment (ansible-runner):

    make ansible-runner-setup

    This will automatically build and start ansible-runner docker container (including all packages and its dependencies), create SSH key for remote connections if not already created (~/.ssh/id_rsa), and create local directories for Ansible inventory, playbooks, and other configuration files.

Ansible configuration

Ansible configuration (variables and inventory files) might need to be adapted to your particular environment

Inventory file

Adjust ansible/inventory.yml inventory file to meet your cluster configuration: IPs, hostnames, number of nodes, etc.

Add Raspberry PI nodes to the rpi group and x86 nodes to x86 nodes.

Se the node, i.e node1, which is going to be used to install non-kubernetes services (dns server, pxe server, load balancer (ha-proxy), vault server). It has to be added to groups dns, pxe, vault and haproxy

Configuring ansible remote access

The UNIX user to be used in remote connections (i.e.: ricsanfre) and its SSH key file location need to be specified.

Modify ansible/group_vars/all.yml to set the UNIX user to be used by Ansible in the remote connection, ansible_user (default value ansible) and its SSH private key, ansible_ssh_private_key_file

  # Remote user name
  ansible_user: ricsanfre

  # Ansible ssh private key
  ansible_ssh_private_key_file: ~/.ssh/id_rsa

By default it uses the ssh key automatically created when initializing ansible-runner (make ansible-runner-setup) located at ~/.ssh directory.

Modify Ansible Playbook variables

Adjust ansible playbooks/roles variables defined within group_vars, host_vars and vars directories to meet your specific configuration.

The following table shows the variable files defined at ansible’s group and host levels

Group/Host Variable file Nodes affected
ansible/group_vars/all.yml all nodes of cluster + pimaster
ansible/group_vars/control.yml control group: pimaster
ansible/group_vars/k3s_cluster.yml all kubernetes nodes (master and workers) of the cluster
ansible/group_vars/k3s_master.yml K3s master nodes
ansible/host_vars/node1.yml external services node specific variables

The following table shows the variable files used for configuring K3S cluster and external services.

Specific Variable File Configuration
ansible/vars/picluster.yml K3S cluster and external services configuration variables. Credentials are fetched on-demand from Vault during deployment.

Prepare PXE server

Get PXE boot files and ISO image to automate x86 nodes installation.

cd metal/x86
make get-kernel-files
make get-uefi-files

Cluster nodes setup

Update Raspberry Pi firmware

Update firmware in all Raspberry-PIs following the procedure described in “Raspberry PI firmware update”

Install gateway node

Install OpenWRT operating system on Raspberry PI or GL-Inet router, gateway node The installation and configuration process is described in “Cluster Gateway (OpenWRT)”

Option 2: Ubuntu OS

gateway router/firewall can be implemented deploying Linux services on Ubuntu 24.04 OS The installation and configuration process is described in “Cluster Gateway (Ubuntu)”

Install external services node

Once gateway node is up and running. External services node, node1 can be configured.

node1 is used to install common services: DNS server, PXE server, Vault, etc.

Install Ubuntu Operating System on node1 (Rapberry PI-4B 4GB).

The installation procedure followed is the described in “Ubuntu OS Installation” using cloud-init configuration files (user-data and network-config) for node1.

User-Data Configuration Network configuration
user-data network-config

Configure external-services node

For automatically execute basic OS setup tasks and configuration of node1’s services (DNS, PXE Server, etc.), execute the command:

make external-setup

Install cluster nodes.

Once node1 is up and running the rest of the nodes can be installed and connected to the LAN switch.

Install Raspberry PI nodes

Install Operating System on Raspberry Pi nodes node2-6

Follow the installation procedure indicated in “Ubuntu OS Installation” using the corresponding cloud-init configuration files (user-data and network-config). IP addresses are assigned statically through node-specific network-config files.

User-Data Configuration Network configuration
user-data network-config

In above user-data files, hostname field need to be changed for each node (node1-node6).

In network-config file addresses field need to be updated for each node (node1-node6), assigning the proper static 10.0.0.X/24 address.

Install x86 nodes

Install Operating System on x86 nodes (node-hp-x).

Follow the installation procedure indicated in “OS Installation - X86 (PXE)” and adapt the cloud-init files to your environment.

To automate deployment of PXE server execute the following command

make pxe-setup

PXE server is automatically deployed in node1 node (host belonging to pxe hosts group in Ansible’s inventory file). cloud-init files are automatically created from autoinstall jinja template. for every single host belonging to x86 hosts group

This file and the corresponding host-variables files containing storage configuration, can be tweak to be adpated to your needs.

autoinstall storage config node-hp-1

If the template or the storage config files are changed, in order to deploy the changes in the PXE server, make pxe-setup need to be re-executed.

Configure cluster nodes

For automatically execute basic OS setup tasks (DNS, DHCP, NTP, etc.), execute the command:

make nodes-setup

Configure External Services

DNS server

Install and configure DNS authoritative server, Bind9, for homelab subdomain in node1 (node belonging to Ansible’s host group dns).

Homelab subdomain is specified in variable dns_domain configured in ansible/group_vars/all.yml and DNS server configuration in ansible/host_vars/node1.yml. Update both files to meet your cluster requirements.

make dns-setup

Create Secret Files

Generate secret files in ~/.secret before deploying external services:

  • ionos-credentials.ini (for IONOS DNS / Let’s Encrypt)
  • github-pat.ini (for FluxCD private repository when git_private_repo=true)
make secret-files

Deploy Minio and Hashicorp Vault

External services including HashiCorp Vault and MinIO are deployed together using the automated orchestration playbook. This process:

  1. Deploys and unseals HashiCorp Vault
  2. Configures Vault with Terraform (KV engine, policies, authentication)
  3. Terraform also generates random credentials used in the cluster and stores all cluster credentials in Vault
  4. Deploys MinIO using credentials from Vault
  5. Configures MinIO with Terraform (bucket and users needed for all backup cluster services)
  6. Loads non-randomized keys in Vault (GitHubPat, DDNS, IONOS, etc.)

Execute the following command:

make external-services

Configuring OS level backup (restic)

Automate backup tasks at OS level with restic in all nodes (node1-node6) running the command:

make configure-os-backup

Minio S3 server VM, s3, hosted in Public Cloud (Oracle Cloud Infrastructure), will be used as backup backend.

Kubernetes Applications (GitOps)

FluxCD is used to deploy automatically packaged applications contained in the repository. These applications are located in /kubernetes directory.

  • Modify cluster configuration to point to your own repository

    Edit kubernetes/clusters/prod/config/cluster.yaml.

    In GitRepository resource definition, set spec.url to the URL of your repository

  • In case of using a private Git repository

    Add following configuration to GitRepository resource

    spec:
  secretRef:
    name: flux-system

  • Modify cluster global variables

    Edit kubernetes/clusters/prod/config/cluster-settings.yaml to use your own configuration. Own DNS domain, External Services DNS names, etc.

  • Tune parameters of the different packaged Applications to meet your specific configuration

    Edit helm chart values.yaml file and other kubernetes manifest files file of the different applications located in /kubernetes directory.

K3S

K3S Installation

To install K3S cluster, execute the command:

make k3s-install

K3S Bootstrap

To bootstrap the cluster, run the command:

make k3s-bootstrap

Flux CD will be installed and it will automatically deploy all cluster applications automatically from git repo.

K3s Cluster reset

If you mess anything up in your Kubernetes cluster, and want to start fresh, the K3s Ansible playbook includes a reset playbook, that you can use to remove the installation of K3S:

make k3s-reset

Shutting down the Pi Cluster

To automatically shut down the cluster, Ansible can be used.

Kubernetes graceful node shutdown feature is enabled in the culster. This feature is documented here. and it ensures that pods follow the normal pod termination process during the node shutdown.

For doing a controlled shutdown of the cluster execute the following commands

  • Step 1: Shutdown K3S workers nodes:

    make shutdown-k3s-worker

  • Step 2: Shutdown K3S master nodes:

    make shutdown-k3s-master

shutdown commands connects to each node in the cluster and execute the command sudo shutdown -h 1m, commanding the node to shutdown in 1 minute.

After a few minutes, all nodes will be shutdown. You can notice that when the Switch ethernet ports LEDs are off. Then it is safe to unplug all nodes.

Updating Ubuntu packages

To automatically update Ubuntu OS packages, run the following command:

make os-upgrade

This playbook automatically updates OS packages to the latest stable version and it performs a system reboot if needed.

Last Update: Mar 01, 2026

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