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Provisioning Fedora CoreOS on the Raspberry Pi 4

prep seperate usb for firmware​

VERSION=v1.32  # use latest one from https://github.com/pftf/RPi4/releases
UEFIDISK=/dev/sdX
sudo mkfs.vfat $UEFIDISK
mkdir /tmp/UEFIdisk
sudo mount $UEFIDISK /tmp/UEFIdisk
pushd /tmp/UEFIdisk
sudo curl -LO https://github.com/pftf/RPi4/releases/download/${VERSION}/RPi4_UEFI_Firmware_${VERSION}.zip
sudo unzip RPi4_UEFI_Firmware_${VERSION}.zip
sudo rm RPi4_UEFI_Firmware_${VERSION}.zip
popd
sudo umount /tmp/UEFIdisk

Install CoreOS tools​

sudo dnf install -y rpi-imager coreos-installer butane ignition-validate

Make working directory and change to it​

mkdir ~/coreos
cd ~/coreos

Download CoreOS image​

coreos-installer download -p qemu -f qcow2.xz --decompress

Rename image to simpler name​

mv *.qcow2 fedora-coreos.qcow2

Create rpict.bu​

variant: fcos
version: 1.4.0
passwd:
  users:
    - name: core
      ssh_authorized_keys:
        - ssh-rsa AAAA...
systemd:
  units:
    - name: serial-getty@ttyS0.service
      dropins:
      - name: autologin-core.conf
        contents: |
          [Service]
          # Override Execstart in main unit
          ExecStart=
          # Add new Execstart with `-` prefix to ignore failure
          ExecStart=-/usr/sbin/agetty --autologin core --noclear %I $TERM
          TTYVTDisallocate=no
    - name: failure.service
      enabled: true
      contents: |
        [Service]
        Type=oneshot
        ExecStart=/usr/bin/false
        RemainAfterExit=yes

        [Install]
        WantedBy=multi-user.target
    - name: etcd-member.service
      enabled: true
      contents: |
        [Unit]
        Description=Run a single node etcd
        After=network-online.target
        Wants=network-online.target

        [Service]
        ExecStartPre=mkdir -p /var/lib/rpict2mqtt
        ExecStartPre=-/bin/podman kill rpict2mqtt
        ExecStartPre=-/bin/podman rm rpict2mqtt
        ExecStartPre=-/bin/podman pull docker.io/gtricot/rpict-mqtt:latest
        ExecStart=/bin/podman run --name rpict2mqtt \
                           --device=/dev/ttyAMA0:/dev/ttyAMA0 \
                            -e MQTT_URL="mqtt://my_mqtt_broker:1883" \
                           -e MQTT_USER="my-super-user" \
                           -e MQTT_PASSWORD="my-secret-password" \
                           -e MQTT_BASE_TOPIC="custom-rpict-topic" \
                           -e ABSOLUTE_VALUES=true \
                           -e SENSOR_VALUE_THRESHOLD=2 \
                            gtricot/rpict-mqtt
        ExecStop=/bin/podman stop rpict2mqtt

        [Install]
        WantedBy=multi-user.target
storage:
  files:
    - path: /etc/hostname
      mode: 0644
      contents:
        inline: |
          tutorial
    - path: /etc/profile.d/systemd-pager.sh
      mode: 0644
      contents:
        inline: |
          # Tell systemd to not use a pager when printing information
          export SYSTEMD_PAGER=cat

Transpile butane file into an ignition file​

butane --pretty --strict rpict.bu --output rpict.ign

Test ignition file in virtual machine​

ignition-validate rpict.ign && echo 'Success!'

Setup the correct SELinux label to allow access to the config​

chcon --verbose --type svirt_home_t rpict.ign

Start a Fedora CoreOS virtual machine​

virt-install --name=fcos --vcpus=2 --ram=2048 --os-variant=fedora-coreos-stable \
    --import --network=bridge=virbr0 --graphics=none \
    --qemu-commandline="-fw_cfg name=opt/com.coreos/config,file=${PWD}/rpict.ign" \
    --disk=size=20,backing_store=${PWD}/fedora-coreos.qcow2

Exit and destroy virtual machine​

CTRL + ] to exit kvm

to destroy run​

virsh destroy fcos
virsh undefine --remove-all-storage fcos

Write to disk​

## set disc
FCOSDISK=/dev/sdX
# Create customized.iso which:
coreos-installer iso customize \
    --architecture=aarch64 \
    --dest-device $FCOSDISK \ # - Automatically installs to /dev/sda
    --dest-ignition config.ign \ # - Provisions with config.ign
    --network-keyfile $networkManagerConnectionFile  \ # -  network configuration
    --ignition-ca ca.pem \ # - Trusts HTTPS certificates signed by ca.pem
    --post-install post.sh \ # - Runs post.sh after installing
    -o custom.iso input.iso

Reference​

FedoraOnRpi

customizing-install

pftf

To do​

  • setup MQTT gateway
  • write CoreOS to SD and boot pi with external monitor
  • test whether /dev/ttyAMA0 is accesible with CoreOS on RPI4