https://github.com/rayui/scooby

Pretty fast, pretty simple K3S clusters for Raspberry Pi
https://github.com/rayui/scooby

bare-metal baremetal k3s k3sup packer raspberry-pi vagrant

Last synced: about 2 months ago
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Pretty fast, pretty simple K3S clusters for Raspberry Pi

• Host: GitHub
• URL: https://github.com/rayui/scooby
• Owner: rayui
• Created: 2022-12-04T02:23:35.000Z (about 2 years ago)
• Default Branch: main
• Last Pushed: 2024-07-25T20:01:09.000Z (5 months ago)
• Last Synced: 2024-08-02T15:46:58.960Z (5 months ago)
• Topics: bare-metal, baremetal, k3s, k3sup, packer, raspberry-pi, vagrant
• Language: Shell
• Homepage:
• Size: 26.4 KB
• Stars: 14
• Watchers: 2
• Forks: 0
• Open Issues: 7
• Metadata Files:
  • Readme: README.md

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README

        
# Scooby

## Self-hosting RPi K3S cluster

Scooby is a build pipeline for creating bare-metal `K3S` clusters of one or more nodes.

Scooby attempts to automate the configuration and deployment of a `K3S` cluster into a single Linux image in a simple, repeatable fashion.

Scooby is designed to be easy to work with and requires a bare minimum of hardware and software configuration to get up and running.

Scooby uses Vagrant, GitHub and optionally, Amazon S3.

Features:

- From commit to bootable image in 15 minutes

- Versioned deployments

- Centralized configuration

- Network booted agents

- Ready-to-go build pipelines

- Github asset storage

- Optional S3 bucket uploader

## Getting started

### Gather required hardware

To get going, you will need at least one Raspberry Pi 3A or higher, and one local storage device (e.g. USB stick) per Pi.

If you are using two or more Pis you will also need a physical Ethernet switch or VLAN group, and the master node will require a second ethernet device.

Several generic USB2 and USB3 devices using the RTL-8152 chipset have been tested and work well. Driverless Ethernet hats should also work but at the current time have not been tested.

Agent nodes perform well on Pi 3A+ but for performance reasons it is recommended to use a Pi 4B or greater for the master node, and a USB3 SSD for master node storage.

To create a three-node Scooby cluster a complete hardware list might be:

- 1x Raspberry Pi 4B

- 1x Raspberry Pi 3B

- 1x Raspberry Pi 3A

- 4x port Ethernet switch

- 1x 1TB USB3 SSD external storage

- 2x 8GB USB2 keys

- 1x RTL8152 USB3 to Ethernet adapter

- 4x Ethernet cables

### Clone the template

Click the `use this template` button above, create a new GitHub repository, and clone it to your local machine.

## Network concepts

The master node in any Scooby cluster of more than one node has two physical ethernet ports and acts as a network gateway for all traffic originating inside the cluster. A Scooby cluster therefore has a concept of `internal` and `external` networks.

The `internal` network is the physical network on which the master and agent nodes communicate, and to which the `eth1` device of the master node is physically connected.

The `external` network is a separate physical network with access to the Internet, and to which the `eth0` device of the master node is physically connected.

All agent nodes' `eth0` devices are connected to the `internal` network.

## Setting up the Master node

The first file you will need to edit is `/config`, in the project root. This file contains information about the cluster's base operating system and network settings. There is an example configured with default values that you can uncomment and change to get you going. For example:

`/config`

```

# Base Raspberry Pi image and SHA

LC_IMAGE_HREF="http://downloads.raspberrypi.org/raspios_lite_arm64/images/raspios_lite_arm64-2022-01-28/2022-01-28-raspios-bullseye-arm64-lite.zip"

LC_IMAGE_SHA=sha256:d694d2838018cf0d152fe81031dba83182cee79f785c033844b520d222ac12f5

# Master node hostname

LC_HOSTNAME=buffy

# DNS providers

LC_PRIMARY_DNS=1.0.0.1

LC_SECONDARY_DNS=

# Master node external network configuration

LC_EXTERNAL_DEVICE=eth0

LC_EXTERNAL_IP=192.168.1.64

LC_EXTERNAL_NET=192.168.1.0/24

LC_EXTERNAL_GW=192.168.1.1

LC_EXTERNAL_DOMAIN=

# Master node cluster network configuration

LC_INTERNAL_DEVICE=eth1

LC_INTERNAL_IP=192.168.64.1

LC_INTERNAL_NET=192.168.64.0/24

LC_INTERNAL_DOMAIN=sunnydale

```

Scooby has been tested with both `bullseye` and `bookworm` releases of `raspios`.

### Static files

Any files placed in the `./server` directory in the project root will be merged into the master node's root filesystem.

For example, `./server/etc/dnsmasq.d/40-hemeryhigh.conf` would be copied to `/etc/dnsmasq.d/40-hemeryhigh.conf` on the master node file system.

Files are persistent and available on first boot.

#### Kubernetes Manifests

Kubernetes manifests should go in `./server/var/lib/rancher/k3s/server/manifests/` in the project root.

## Setting up the Agents

### Enable Pi network boot

Each agent must be setup for network booting. This part cannot be automated and you should perform it manually on each agent. Fortunately, it needs only to be done once and does not need to be done at all on the Pi 4.

Mete Balci has written an excellent guide detailing [how to configure Raspberry Pi for network boot](https://metebalci.com/blog/bare-metal-rpi3-network-boot/) :clap:.

The official Raspberry Pi documentation for [debugging network book mode](https://www.raspberrypi.com/documentation/computers/raspberry-pi.html#debugging-network-boot-mode) is also very useful.

### Agent definition

Create one file for each of the agent nodes in the `./agents` directory. This file contains information about the agent's network settings, storage and `K3S` arguments specific to that node. The name of the file should be the hostname of the agent with an extension of `.agent`.

For each agent, you will need to provide:

- the agent node's hardware address

- its IPv4 address

- a UUID for a partition containing an ext4 filesystem for `K3S` persistent local storage

- an optional UUID for a swap partition

- its PXE client ID

- any extra args for K3s that the agent might need (optional)

For example:

`./agents/willow.agent`

```

AGENT_ETHERNET=b8:27:eb:81:1a:52

AGENT_IP=192.168.64.65

AGENT_RANCHER_PART_UUID=d5f9e6c2-493c-48da-baf2-0c63dd7a36b1

AGENT_PXE_ID=c6811a52

AGENT_K3S_ARGS=

```

- An incomplete or incorrect agent description will not result in a working agent node.

#### Finding the PXE ID

The Pi transmits its serial number for PXE boot. Find the serial number of any Raspberry Pi with the following command:

```

$ cat /sys/firmware/devicetree/base/serial-number

```

#### Local Storage

Although the agents' operating systems are served over the network, `K3S` requires some storage on each agent's local filesystem.

Scooby agents expect an ext4 partition on any local storage media, although USB is highly recommended due to the relative volatility of many SD cards.

You can find the UUID of any partition using `blkid`. To find the partition UUID of /dev/sda1, for example:

```

$ blkid --match-tag="PARTUUID" /dev/sda1

```

- Ensure you don't have any bootable physical media in the Pi when you power it up

- If you have several agents, it can be helpful to write the name of the intended agent on the USB key to ensure the correct key is matched with the correct agent host.

## Building

### Building with Github Actions

By default, a commit to main will trigger the build job. When the build has completed you will see a zipped asset available to download in the `build` workflow.

You can enable builds on branch commits by removing the following line

`./github/workflows/branch.yml`

```

    if: false

```

### Build locally

To build Scooby locally, you must first install Vagrant. On Debian-like systems you can do this with the following command:

```

apt install vagrant

```

Then, execute the following command in the project root:

```

$ ./scripts/build.sh

```

The output disk image will be found in `./images/scooby.img`. The image is typically in the region of 3.5GB.

### Defaults

Building with the defaults will produce a deployable image that:

- has only a master node

- contains no manifests

- cannot be accessed by SSH

### Secret environment variables

Scooby has the following secrets:

`LC_DEFAULT_USER` name of your default user for the cluster (default: spike)  

`LC_SSH_AUTH_KEY` an SSH auth key to access the cluster nodes (optional)  

`LC_PACKER_GITHUB_API_TOKEN` your Packer API token (optional)

- If you are building locally, you will need to set the secret environment variables in a file called `.env` in the project root.

- If you are building using the GHA pipeline, you will need to set these as action secrets in your repository settings.

### AWS S3 secrets

If you commit to main, Scooby can also attempt to upload the finished image to an AWS S3 bucket.

To enable S3 upload, create these secrets in your repository settings.

`AWS_ACCESS_KEY_ID` the Key ID for your AWS account  

`AWS_SECRET_ACCESS_KEY` the Secret Access Key for your AWS account  

`AWS_BUCKET_S3_URI` the S3 URI for your bucket account  

`AWS_REGION` the AWS region in which your bucket is located

### Action Runners

For convenience, Scooby is configured to use macos-latest by default. This is the only GitHub runner that currently provides Vagrant.

A self-hosted runner is recommended if you plan to make frequent changes.

If you wish to use a self-hosted runner, you will need to edit `.github/workflows/build.yml` and change `runs-on: macos-latest` to `runs-on: self-hosted`.

You will then need to follow [these instructions](https://docs.github.com/en/actions/hosting-your-own-runners/managing-self-hosted-runners/adding-self-hosted-runners) to host your own runner.

## Deploying

### Clone image

Once you have built and downloaded the image, use `dd` to transfer it to the master node's storage device. If your master node's storage device appeared as `/dev/sdf`, for example:

```

$ dd oflag=sync bs=1M if=~/Downloads/scooby.img of=/dev/sdf

```

### Connect the Pis to the network

A typical Scooby network might look something like this:

```mermaid

graph TD;

  PublicNetwork-->Buffy;

  Buffy-->Xander;

  Buffy-->Willow;

  Buffy-->Cordy;

  Buffy-->Giles;

```

As explained earlier, the master node acts as a gateway for all network traffic originating inside the cluster that is destined for `external` networks. NAT is enabled for the agents using `iptables-persistent`.

Scooby is configured such that master node's `eth0` (the onboard Ethernet device) is the cluster's `external` or public interface, and `eth1` (e.g. the RTL-8152) is the `internal`, or cluster interface. Agent node `eth0` devices should exist on the same network as the master node's `eth1` device.

Clients on the external network may access services on the cluster via the master node's `eth0` device. Traefik cannot provide IP addresses by itself so it is recommended to provide them on the master node's `eth0` device with a MetalLB deployment on the master node.

To enable network boot services for agent nodes, the master node uses `dnsmasq` to provide PXE and DHCP services to the cluster on its `eth1` device. You should therefore not connect the master node's `eth1` device to any network with existing DHCP services.

Scooby uses Ethernet only. Wifi is not currently supported.

## Power up the cluster

Once all your Pis are plugged into the network and all your storage devices are attached, it is time to power up the master node.

A master node called `buffy` would be ready when you see the following in the master node console:

```

BUFFY WILL PATROL TONIGHT

```

Be patient; this process can about take 7 minutes on a Pi 4B. Allow the master node a few more minutes following the above message before powering up any agents. `cloud-init` config files are served to the agents by `lighttpd` and it takes a few moments to start responding.

You can watch the progress of your agent nodes coming online with the following command in a terminal session on the master node:

```

$ kubectl get nodes -Aw

```

Eventually you should be rewarded with something like:

```

NAME     STATUS   ROLES                  AGE   VERSION

buffy    Ready    control-plane,master   25h   v1.27.4+k3s1

willow   Ready                     25h   v1.27.4+k3s1

xander   Ready                     24h   v1.27.4+k3s1

cordy    Ready                     25h   v1.27.4+k3s1

```

Congratulations! Your Raspberry Pi supercomputer is now complete :blush:

## Notes

### First boot

The master node will appear to go quiet on first boot.

There will be no console output after `cloud-init` has identified the network devices for about four minutes. This is a known issue, and is caused by `cloud-init` waiting for eth0 to become ready.

Cloud-init will eventually find the network interface and continue.

### Pi user

The default Raspberry Pi user `pi` is disabled for security reasons.

### RTL-8152

RTL-8152 USB to Ethernet devices are a good solution for adding extra connectivity to the Raspberry Pi but they can appear to the operating system as USB storage media when first inserted.

To ensure the device appears as an Ethernet device and not USB storage, add the following file to your project:

`/server/etc/udev/rules.d/10-modeswitch.rules`

```

ACTION=="add", SUBSYSTEM=="usb", ENV{ID_VENDOR_ID}=="0bda", ENV{ID_MODEL_ID}=="8152", RUN+="/usr/bin/usb_modeswitch -K -v 0bda -p 8151;/usr/bin/usb_modeswitch -v 0bda -p 8152 -R"

```

### MetalLB

Use MetalLB to provide IP addresses for all your K3S services. An example MetalLB manifest in a Scooby deployment might look like the following:

`/server/var/lib/rancher/k3s/server/manifests/metallb.yml`

```

apiVersion: v1

kind: Namespace

metadata:

  name: metallb-system

---

apiVersion: helm.cattle.io/v1

kind: HelmChart

metadata:

  name: metallb-system

  namespace: kube-system

spec:

  repo: https://charts.bitnami.com/bitnami

  chart: metallb

  targetNamespace: metallb-system

---

apiVersion: metallb.io/v1beta1

kind: IPAddressPool

metadata:

  name: first-pool

  namespace: metallb-system

spec:

  addresses:

    - 192.168.1.65-192.168.1.127

---

apiVersion: metallb.io/v1beta1

kind: L2Advertisement

metadata:

  name: public-pool

  namespace: metallb-system

spec:

  interfaces: ["eth0"]

  ipAddressPools:

    - first-pool

  nodeSelectors:

    - matchLabels:

        kubernetes.io/hostname: buffy

```

### Pihole

You can easily deploy Pihole to a Scooby cluster with a manifest like this:

`/server/var/lib/rancher/k3s/server/manifests/pihole.yml`

```

apiVersion: v1

kind: Namespace

metadata:

  name: pihole

  labels:

    name: traffic

---

apiVersion: helm.cattle.io/v1

kind: HelmChart

metadata:

  name: pihole

  namespace: pihole

spec:

  chart: pihole

  targetNamespace: pihole

  repo: https://mojo2600.github.io/pihole-kubernetes/

  valuesContent: |-

    ...

```

Pihole works well for DNS, but load balancers aren't designed to respond to broadcast traffic like DHCP requests.

### DHCP

You might find that Scooby's dnsmasq instance is an easier solution for serving DHCP to your `external` network than Pihole. Here is an example configuration file that will do that:

`/server/etc/dnsmasq.d/10-external-dhcp.conf`

```

domain=magicbox,192.168.1.0/24

interface=eth0

dhcp-range=tag:eth0,192.168.1.128,192.168.1.240

dhcp-option=tag:eth0,option:router,192.168.1.1

dhcp-option=tag:eth0,6,192.168.1.66

dhcp-host=30:05:5C:8E:ED:C3,192.168.1.10,snyder

dhcp-host=08:00:20:AA:BB:CC,192.168.1.11,joycey

```

### OverlayFS

Scooby uses OverlayFS for agent filesystems. Under some circumstances you may wish to return an agent to its pristine state and re-deploy it without re-deploying the entire cluster.

To do this, you will need to SSH into the master node and execute the following as root, changing the hostname to match the agent node in question.

```

$ exportfs -u faith:/mnt/scooby/agents/faith

$ umount /mnt/scooby/agents/faith

$ rm -rf /var/lib/scooby/agents/faith/*

$ rm -rf /var/lib/scooby/overlay/faith/*

$ mount -a

$ exportfs -a

```

### Accessing devices

Raspberry Pis are often used for IoT applications. Scooby provides a very convenient method of remotely managing IoT devices when used with [Smarter Device Manager](https://gitlab.com/arm-research/smarter/smarter-device-manager) published by [Arm Research](https://www.arm.com/resources/research).

To access devices such as USB, GPIO pins, V4L and I2C and more from within `K3S`, download the following files from the Smarter Device Manager repo to `./server/var/lib/rancher/k3s/server/manifests/`

- [Raspberry Pi K3S config map](https://gitlab.com/arm-research/smarter/smarter-device-manager/-/raw/master/smarter-device-manager-configmap-rpi.yaml?ref_type=heads&inline=false)

- [Raspberry Pi K3S daemon set](https://gitlab.com/arm-research/smarter/smarter-device-manager/-/raw/master/smarter-device-manager-ds-with-configmap-rpi-k3s.yaml?ref_type=heads&inline=false)

Provide each agent hosting a device with a `K3S` node label of `smarter-device-manager=enabled`. An agent description file for a node with device access enabled might look like the following:

`./agents/ted`

```

AGENT_ETHERNET=b8:27:eb:86:53:3c

AGENT_IP=192.168.64.254

AGENT_RANCHER_PART_UUID=b357bda8-b641-41eb-9b5d-b3c5486e50e7

AGENT_PXE_ID=9686533c

AGENT_K3S_ARGS="--node-label 'smarter-device-manager=enabled'"

```