jonlamb-gh / rpi4-yocto-stratum-1-ntp-server

RPi4 Stratum-1 NTP Server Image

Chrony stratum-1 time server using gpsd with pps.

TODO

• update these docs
• update iptables rules

Hardware

• Raspberry Pi 4
• Raspberry Pi 4 Ultra-Thin CNC Aluminum Alloy Passive Cooling Case
• 5V 3A USB-C Power Supply
• GPS HAT
• CR1220 12mm Diameter - 3V Lithium Coin Cell Battery
• GPS antenna
• SMA to uFL/u.FL/IPX/IPEX RF Adapter Cable

Config

TODO

Build

Setup environment:

export IPTABLES_ICMP_ALLOW_IP_RANGE='a.b.c.d-a.b.c.e'
export BB_ENV_EXTRAWHITE="$BB_ENV_EXTRAWHITE IPTABLES_ICMP_ALLOW_IP_RANGE"

export IPTABLES_SSH_ALLOW_CIDR='a.b.c.d/e'
export BB_ENV_EXTRAWHITE="$BB_ENV_EXTRAWHITE IPTABLES_SSH_ALLOW_CIDR"

export IPTABLES_DNS_SERVER_IP='a.b.c.d'
export BB_ENV_EXTRAWHITE="$BB_ENV_EXTRAWHITE IPTABLES_DNS_SERVER_IP"

export SSH_AUTH_KEYS_ME_USER='/path/to/authorized_keys'
export BB_ENV_EXTRAWHITE="$BB_ENV_EXTRAWHITE SSH_AUTH_KEYS_ME_USER"

./setup

./build

Deploy to SD Card

Find the image files:

bitbake -e rpilinux-image | grep ^DEPLOY_DIR_IMAGE

# dtb
cd /path/to/build/tmp/deploy/images/raspberrypi4-64/
cp bcm2711-rpi-4-b.dtb /media/card/BOOT/

# firmware
cd /path/to/build/tmp/deploy/images/raspberrypi4-64/bcm2711-bootfiles
cp -a ./* /media/card/BOOT/

# kernel
cp Image /media/card/BOOT/kernel_rpilinux.img

# rootfs
cd /media/card/ROOT/
sudo tar -xjf /path/tobuild/tmp/deploy/images/raspberrypi4-64/rpilinux-image-raspberrypi4-64.tar.bz2

Initial Setup

• Change the root password, default is root

  passwd

Useful Commands

chronyc sources

chronyc tracking

gpsmon time.home

Links

• OpenEmbedded Layer Index : zeus
• Linux Hardening