Generate both a SD card and a thumb drive with customizations before booting your RPi for the first time using arbitrary linux disk images.t
Two primary concerns drove this work. First, getting an RPi that is intended to be headless onto a network can be terrible. Ideally, you'd have a space monitor, keyboard, and plenty of desk space to quickly set up / manually configure / finally tear back down.
The second problem is that, god dammit, SD cards are terrible.
No matter what I do, my power is not reliable, and that means
my SD cards end up corrupt in awful places (e tu,
so relying on the SD card as little as possible makes sense.
First Solution: Polish the Root Partition at Flash Time
We have access to the root partition when we flash it to a device, and most of the polish I apply to RPis before calling them done is a handful of changes to disk. So when flashing the root partition, lets also polish it: add some security and QoL support.
In fact, it makes the most sense to automate the whole process in three steps: first clear the media, then flash it, then polish. No need to remove or take user input, like any good deployment system.
Here are the changes made to the stock Raspbian install:
- Change password auth policy for ssh connections to "no thanks" ** Friends dont let friends connect with insecure passwords.
- Create a .ssh directory with correct perms
- Populate pi's
- Populate wpa_supplicant.conf with provided psk and ssid ** Allows the RPi to "just connect" on first boot to the Wifi.
Now the boot drive is provisioned such that the RPi will connect on first boot to the wifi in a secured way, and support SSH access using the private key auth. Perfect!
Easiest way to limit the risks inherent in booting to an SD card is to use it for the bare minimum- only for booting.
The script will set up a second media device, a thumb drive, to store the mounted root partition. In practice, this is significantly more stable than booting directly to the SD card, and I've gone from one SD card failure every couple of months to zero failures using this method (YMMV though).
This whole idea is taken from the great instructables guide here: https://goo.gl/hzk6fk.
Installation / Requirements
Needs python 2.7 and to be run from a linux system, in my case Ubuntu 16.04. Needs passwordless sudo.
No other python dependencies, just stdlibs. Like a boss.
./run.py command and then follow the interactive
prompts. It takes some guesses about your system (that I
use to protect my own), like it won't let you mess with the
sda device by accident.
Some of this will be made obsolete once RPis have proper boot-from-USB support, which has been in testing since for- ever. That said, I still use this regularly to make quickly bootstrapped RPis, and see a couple of improvements that I'd like to tackle:
- Clean up more of the hard codes
- Support more than just Raspbian
- Turn into a proper python package and publish to PyPi