This mainly demonstrates my goal of preparing a Raspberry Pi to be provisioned prior to its first boot. To do this I have chosen to use the same cloud-init that is the standard for provisioning servers at Amazon EC2, Microsoft Azure, OpenStack, etc.

I found this to be quite challenging because there is little information available for using cloud-init without a cloud. So, this project also servers as a demonstration for anyone on any version of Linux who may want to install from source, and/or use without a cloud. If you fall into that later group, you probably just want to read the code. It's bash so everything I do, you could also do at the command line. (Even the for loop.)

1. Download the lastest Raspbian release and write it to a microSD card. (This can be done from Mac, Windows, or of course Linux.)
2. On the microSD card, create an empty file named ssh and one named wpa_supplicant.conf (If you are on a Linux machine, you'll have to make sure this is going into the boot partition. On any other OS, the boot partition is the only one that can be mounted.)
3. Put your wifi settings into the wpa_supplicant.conf file. (There is a pretty handy online generator you can use.)
4. Save this script onto the microSD card.
5. Save this modified cmdline.txt file onto the microSD card.
   • Alternatively, you could just put ds=nocloud;seedfrom=/boot/;instance-id=iid-raspberrypi-nocloud at the end of the existing one. That is all I did.
6. Eject the card. Place it in your Raspberry Pi. Boot it up.
7. Locate your Raspberry Pi on your network.
   • Most modern routers will allow you to reach it via the hostname it declares, like so: raspberrypi.local
   • If that doesn't work in the next step, find the IP address via:
     • sudo nmap -sP $(route -n get 8.8.8.8 | awk '$1=="gateway:"{print $2}')/24 | awk '/^Nmap/{ip=$NF}/B8:27:EB/{print ip}'
     • That works for Mac and Linux. I have no idea how to do that in Windows.
8. SSH into the Raspberry Pi like so:
   • ssh [email protected]
   • The password is raspberry.
9. Run the script that we saved in Step 4 above.
   • /boot/cloud-init-setup.sh
   • You will be prompted for a password. Again, it is raspberry.

Before rebooting you will find this:

pi@raspberrypi:~ $ find /boot/per*
/boot/per-boot
/boot/per-boot/01_get_ready.sh
/boot/per-boot/02_do_it.sh
/boot/per-once
/boot/per-once/01_prepare.sh
/boot/per-once/02_install_stuff.sh
pi@raspberrypi:~ $ ls -la
drwxr-xr-x 16 pi   pi      4096 Feb 21 10:02 cloud-init-master
-rw-r--r--  1 pi   pi   1180953 Feb 21 10:01 cloud-init-master.zip

After 1 reboot you will find this:

pi@raspberrypi:~ $ find /boot/per*
/boot/per-boot
/boot/per-boot/01_get_ready.sh
/boot/per-boot/02_do_it.sh
/boot/per-once
/boot/per-once/[email protected]
/boot/per-once/[email protected]
pi@raspberrypi:~ $ ls -la
drwxr-xr-x 16 pi   pi      4096 Feb 21 10:02 cloud-init-master
-rw-r--r--  1 pi   pi   1180953 Feb 21 10:01 cloud-init-master.zip
-rw-r--r--  1 root root      62 Feb 21 10:04 per-boot.out
-rw-r--r--  1 root root      68 Feb 21 10:04 per-once.out
pi@raspberrypi:~ $ for f in per*; do echo $f; cat $f; done
per-boot.out
21/02/18 10:04:52 - 01_get_ready
21/02/18 10:04:52 - 02_do_it
per-once.out
21/02/18 10:04:52 - 01_prepare
21/02/18 10:04:52 - 02_install_stuff

After a 2nd reboot you will find this:

pi@raspberrypi:~ $ for f in per*; do echo $f; cat $f; done
per-boot.out
21/02/18 10:04:52 - 01_get_ready
21/02/18 10:04:52 - 02_do_it
21/02/18 10:06:12 - 01_get_ready
21/02/18 10:06:12 - 02_do_it
per-once.out
21/02/18 10:04:52 - 01_prepare
21/02/18 10:04:52 - 02_install_stuff

As you can see, the scripts in /boot/per-boot/ run on every boot. The scripts in /boot/per-once/ ran once and then got renamed. If you were to change their extension back to .sh they would run once again..