Ubuntu Server

The K3s cluster can be provisioned into any type of bare-metal hardware. This repository uses Raspberry Pi’s as bare-metal hardware example, therefore is recommended to install the latest Ubuntu Server LTS 24.04+ (64-bits) OS with Raspberry Pi Imager.

OS Installation

Each cluster node uses Ubuntu Server LTS 24.04+ (64-bits) OS installed, which is a requirement for Cilium. The apt package dependencies changed, compared to previous 22.04 release, therefore, 24.04+ release is enforced as minimal requirement.

Note

For generic hardware, install the OS using your favorite provisioning method.

Software

Run the following command to install the Raspberry Pi Imager software:

brew install raspberry-pi-imager

OS General Settings

On each cluster node, under OS Customisation: General section, set only the hostname, username and password, as well the locale values:

OS General Settings: Imager General

Important

Use the username defined above to set the ansible_username variable.

OS Services

On each cluster node, under OS Customisation: Services section, enable SSH with password authentication:

OS General Settings: Imager Services

Hardware

See the cluster_vars.hardware settings listed below, defined into main.yaml defaults file.

`hardware.architecture`

Hardware architecture used to identify the cluster node hardware architecture. To determine the hardware architecture, run:

arch

Command output:

aarch64

Important

Certain roles install required binaries, dependent on the hardware architecture.

Example for k3s binary defined into main.yaml defaults file:

k3s_vars:
  release:
    k3s:
      checksum: sha256sum-arm64.txt
      file: k3s-arm64
      name: k3s

The correct hardware architecture value for arm64 should be aarch64, with a file named k3s-aarch64, which unfortunately is not the naming convention used into GitHub repositories. Linux kernel community have chosen to call their kernel port arm64 (rather than aarch64), hence the use of hardcoded values.

`hardware.product`

Hardware product, used to identify the cluster node hardware model. To determine the hardware product, run:

lshw -class system -quiet | grep product

Command output:

product: Raspberry Pi 4 Model B Rev 1.5

Storage Devices

See the cluster_vars.device settings listed below, defined into main.yaml defaults file.

Note

To prevent premature wear and improve system performance, the Provisioning playbook disables the atime timestamp on storage device mounts.

`device.enabled`

Setting the value to false will assume the storage devices are internal and disable any configuration settings related to storage devices attached to hardware through USB cable adapter.

Validate the storage devices attached with a USB cable adapter to hardware, by running the lsusb command:

lsusb

Command output:

Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 002: ID 174c:55aa ASMedia Technology Inc. ASM1051E SATA 6Gb/s bridge, ASM1053E SATA 6Gb/s bridge, ASM1153 SATA 3Gb/s bridge, ASM1153E SATA 6Gb/s bridge
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 002: ID 2109:3431 VIA Labs, Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

For example, connecting the storage device with different USB cable models might result in a different device.name. Similarly, connecting the storage device to a different USB port will result in a different device.id.

Tip

Run the Validation playbook, to validate the USB storage device values.

`device.id`

The storage device attached with a USB cable adapter to hardware is identified as Bus 002 Device 002, which sets the device.id to 2:2. To test if the value is correct, run:

lsusb -s '2:2'

Command output:

Bus 002 Device 002: ID 174c:55aa ASMedia Technology Inc. ASM1051E SATA 6Gb/s bridge, ASM1053E SATA 6Gb/s bridge, ASM1153 SATA 3Gb/s bridge, ASM1153E SATA 6Gb/s bridge

`device.name`

The storage device USB cable adapter chipset is identified as ASMedia Technology Inc. bridge, which sets the device.name to ASMedia Technology. To test if the value is correct, run:

lsusb -s '2:2' | grep 'ASMedia Technology'

Command output:

Bus 002 Device 002: ID 174c:55aa ASMedia Technology Inc. ASM1051E SATA 6Gb/s bridge, ASM1053E SATA 6Gb/s bridge, ASM1153 SATA 3Gb/s bridge, ASM1153E SATA 6Gb/s bridge

Hostname Validation

Depending on what network router you use, the hostname might not resolve correctly in Ubuntu. Prior cluster deployment, verify the hostname FQDN is correctly set.

Server Login

ssh apollo

Validation

Validate the /etc/hosts configuration:

cat /etc/hosts | grep apollo

If the output is as listed below, no action is required:

127.0.1.1 apollo.local apollo

Note

The Provisioning playbook will validate on each cluster node if the above format is respected, and correct it if needed.

You can check the detected server node FQDNs, by running:

hostname --all-fqdns

The output should be:

apollo.local apollo

Handbook Network