125 lines
4.0 KiB
Org Mode
125 lines
4.0 KiB
Org Mode
#+NAME: Raspberry pi k3s cluster guide
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#+AUTHOR: James Blair
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#+EMAIL: mail@jamesblair.net
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#+DATE: 26th October 2019
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This file serves as a complete step by step guide for creating a bare
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metal raspberry pi kubernetes cluster.
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* Pre-requisites
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- This guide uses the [[https://k3s.io/][k3s]] distribution of kubernetes from Rancher.
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I chose this distribution because it is a CNCF certified production
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grade implementation that is optimised for lightweight implementations
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such as ARM.
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- For this guide I am using three [[https://www.pishop.us/product/raspberry-pi-4-model-b-4gb/][Raspberry Pi 4 4GB]] machines.
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The cluster will have one leader node and two worker nodes.
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For resiliency puposes in future I will update the cluster to run
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with two leader nodes.
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- This guide requires each Raspberry Pi to have a removable SD card or
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other removable boot media. I am use three 32GB SD Cards though any
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USB or SD card at least 8GB in size should work fine.
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* Step 1 - Downloading the operating system
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Our first step is to download an image of the latest version of
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[[https://downloads.raspberrypi.org/raspbian_lite_latest][raspbian lite]]. This is a minimal debian based distribution optimised
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for rapsberry pis.
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*Note:* There the raspberry pi download site provide a SHA-256 hash that
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can be used to verify downloads. While not covered in this guide this
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is reccomended to ensure the image you download is genuine.
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#+NAME: Download the os image
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#+BEGIN_SRC shell
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cd ~/Downloads/
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wget 'https://downloads.raspberrypi.org/raspbian_lite_latest'
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#+END_SRC
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* Step 2 - Write the image file to removable media
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Our next step is to write the downloaded image file to our removable
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media. This step needs to be repeated for each raspberry pi in the
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cluster.
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*Note:* As my development environment is based on [[https://docs.microsoft.com/en-us/windows/wsl/about][wsl]] I need to use
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a third party tool to write the image. If you are on a standard linux
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distribution you can use the ~dd~ utility to write the image.
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The image writing utility I use is [[https://www.balena.io/etcher/][balena etcher]]. After downloading
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the latest version:
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- Insert your removable media.
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- Select the image file you downloaded earlier.
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- Select your removable media and start writing the image.
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* Step 3 - Enable ssh at startup
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As our cluster will be headless, i.e. have no screen keyboard or mouse
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plugged in we need to ensure ssh is configured from boot so that we can
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remotely connect.
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To do this we just need to add an empty file named ~ssh~ to our newly
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created sd card
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#+NAME: Mount newly formatted sd card
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#+BEGIN_SRC shell
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sudo mkdir /media/sdcard
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sudo mount /dev/[SDCARD] /media/sdcard -o umask=000
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#+END_SRC
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#+NAME: Create the blank ssh file in the boot directory
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#+BEGIN_SRC shell
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sudo touch /media/sdcard/ssh
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#+END_SRC
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* Step 4 - Enable wifi at startup
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For this guide we are running our cluser wirelessly. To ensure we can
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access our pi's once they boot we need to ensure they boot with a wifi
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configuration that will connect to our desired network.
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To achieve this we need to set a configuration for the [[https://en.wikipedia.org/wiki/Wpa_supplicant][wpa_supplicant]]
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application that our raspberry pi's use for managing wireless.
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For security reasons I don't store wireless access point details here.
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Instead they are retrieved at runtime of the code block using the
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[[https://bitwarden.com/][bitwarden]] command line utility.
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#+NAME: Write the wireless configuration file
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#+BEGIN_SRC shell
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export WIRELESS_SSID=`bw get username wifi`
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export WIRELESS_PASS=`bw get password wifi`
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cat > /media/sdcard/wpa_supplicant.conf << EOF
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country=nz
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update_config=1
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ctrl_interface=/var/run/wpa_supplicant
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network={
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scan_ssid=1
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ssid=$WIRELESS_SSID
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psk=$WIRELESS_PASS
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}
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EOF
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#+END_SRC
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After writing the file we will use ~cat~ to verify the details.
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If all details are correct you can unmount and remove the media.
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