RPI-Setup (WIP)

Purpose

This repository allows you to set up a Raspberry Pi solely by writing to the /boot partition (i.e. the one you can write from most computers!) in a repeatable manner. This allows you to distribute a small .zip file to set up a Raspberry Pi to do anything. You tell the user to unzip it over the top of the Pi's boot partition - the system can set itself up perfectly on the first boot, and once everything is ready to go reboot.

This is done using pi-init2. You can read more about how it works behind the scenes here. Additionaly pi-init2 various system files are symlinked back to the /boot, allowing you to reliably edit those "user-serviceable" files from the computer in future.

Another thing this repository will do is automated setting up the SD card in read-only mode as described here. This is especially important for cases where the pi can get its power cut off without propper shutdown (for example in robotics) as it will prevent SD card corruption. This adds an (ro) (read-only) indicator to the bash prompt indicating that the file system can't be changed. To make changes you can use the rw and ro bash commands to transision between read-write and read-only modes respectivaly. A number of directories (including /tmp, /var/log and /var/tmp) are remapped to a tmpfs to ensure programs that expect them to be writable contiune to work.

Setting up the SD card for the PI

From your desktop / laptop:

• Download and write a standard Raspbian Buster Lite SD card. Use this version so everyone is using the same version. We recomend using etcher to flash the card
• Download the latest release of this repository into the /boot partition. Unzip and move all the files into the /boot folder (replace any files that conflict so the repository's version overwrites the original version). Delete the zip file and now empty folder.
• Remove the SD card and put it into your Pi.

The Raspberry Pi should now boot and set everything up for development.

Getting internet access at Stanford

This script will make so the RPi automatically wants to connect the Stanford network. Initially it won't be able to do that as it is not yet authenticated to do it. To set that up:

• Plug your Pi in to power (over the onboard micro USB port). Either plug a monitor and keyboard into the Pi or SSH into it using your laptop over Ethernet. Log in to the Pi. In the welcome message that comes after the login line, look for the Pi's MAC address, which will appear under the line that says "wireless Hardware MAC address". Note that address down.
• Use another computer to navigate to iprequest.stanford.edu.
• Log in using your Stanford credentials.
• Follow the on-screen instructions to add another device:
  • First page: Device Type: Other, Operating System: Linux, Hardware Address: put Pi's MAC address
  • Second page: Make and model: Other PC, Hardware Addresses Wired: delete what's there, Hardware Addresses Wireless: put Pi's MAC address
• Confirm that the Pi is connected to the network:
  • Wait for an email (to your Stanford email) that the device has been accepted
  • sudo reboot on the Pi
  • After it's done rebooting, type ping www.google.com and make sure you are receiving packets over the network

Getting internet access elsewhere

There are two methods for getting internet access elsewhere: using the raspi-config tool on the Pi or changing the wpa_supplicant file in the SD card file system. Using the raspi-config tool is simpler and recommended for beginners, but the benefits of modifying the wpa_supplicant file is that you can set the proper internet settings before starting up the Pi, which may help in scenarios where you'd like to do as little setup on the Pi as possible.

1. Raspi-config method

   Once SSH'd into the Pi, run:

   sudo raspi-config

   Then go to Network Options and follow the prompts to connect to Wifi.

2. Wpa_supplicant method

   Edit /etc/wpa_supplicant/wpa_supplicant.conf as documented here and reboot. Thanks to pi-init2 magic that file can be edited before the pi is ever turned on from /boot/appliance/etc/wpa_supplicant/wpa_supplicant.conf

Getting started with the Pi

• Configure your computer to access the robot network:
  • Go to your network settings for the interface you wish to use (ethernet/wifi)
  • Change your Configure IPv4: Manually
  • Change your IP Address to something in range 10.0.0.X (If you ar part of Stanford Student Robotics pick something that doesn't colide with other systems from this document)
  • Change your Subnet Mask: 255.255.255.0
  • Leave the Router blank
  • After disconnecting from the robot network remember to return those settings to what they orignially were, otherwise your internet on that interface won't work
• Ssh into the pi using ssh pi@10.0.0.10 from your computer
• Type rw to enter read-write mode. Confirm that the terminal prompt ends with (rw) instead of (ro)
• Run sudo ./install_packages.sh to install packages
  • If the IP is still 10.0.0.10 you will be prompted to change it
  • If the hostname is still raspberry you will be prompted to change it
  • You will be asked to enter the current time and date. This is needed so that certificates don't get marked as expired. There is a time_sync.sh script that updates the current time from google

What this repo does

• Enables ssh. Because the password is kept unchanged (raspberry) ssh is only enabled on the ethernet interface. Comment out the ListenAddress lines from /boot/appliance/etc/ssh/sshd_config to enable it on all interfaces.
• Sets the Pi to connect to the robot network (10.0.0.X) over ethernet
• Expands the SD card file system
• Sets the file system up as read-only
• Prepares to connect to Stanford WiFi (see above for details)
• Gives the script to install tools and repos needed for development

Building pi-init2

This repo inculdes the pi-init2 binary and there shouldn't be any reason to recompile it. If you need to there is a included Makefile