Update RPIs to use .gitconfig and .netrc

skolo/raspberry-pi/README.md

 # Skolo + Raspberry Pi
 
 Skolo has a fleet of Raspberry Pis that are attached to one (and only one) Android device.
 
 This directory contains scripts for making that all happen.
 
 This is meant to be a detailed description, with [this design doc](https://docs.google.com/document/d/1bbEfQSZvAk5yIpq4Ey1gGgGQscdO9KB0Jfe962XcowA/edit#)
 acting as a high level overview.  If the current setup is lost in a fire and this document is the
 only thing remaining, it should be sufficient to fix Skolo.
 
@@ skipping 50 matching lines @@
 passwd root
 
 # Make our user for swarming
 adduser chrome-bot
 # Use/Put the password in the password manager.
 
 # Load some android public/private keys for python-adb to use into /home/chrome-bot/.android
 # Download from https://pantheon.corp.google.com/storage/browser/skia-buildbots/rpi_auth/?project=google.com:skia-buildbots
 # then use chown to make chrome-bot own them.
 
+# Take the rpi-master and rpi-spare ssh public keys and put them in /home/chrome-bot/.ssh/authorized_keys
+
+# Acquire .gitconfig and .netrc for the bots. Put them in /opt/
+# Design decision note:  These configs may change; by putting them in /opt/ with
+# a script to copy them to $HOME on boot, new keys can be deployed by updating
+# them in /opt and then rebooting the rpis. If a faster deploy is required, then
+# they can be put in /opt and deployed immediately using Ansible. There is more
+# flexibility this way. (Reminder that $HOME is not NFS mounted, and so updating
+# $HOME on the master image does not autoupdate all the pis)
+
 # Ctrl+D to exit chroot
 ```
   - `./setup-swarming.sh`  This will do all automatic, idempotent setup that is possible.  If Ansible can be configured to act inside a chroot, this should be ported to Ansible.
   - `ansible-playbook -i "localhost," -c local finalize_image.yml`  finalize_image copies any scripts we need, changes any additional files that can be done in an automated way.
   - The mounted image file has been receiving the changes this entire time, no need to `dd` anything to back it up.  Current backups are in gs://skia-images/Swarming
   - See "Begin serving the image"
 
 ## Begin serving the image
 By default, the script is looking for `/opt/rpi_img/prod.img`
 
     ansible-playbook -i "localhost," -c local start_serving_image.yml
 
 To being serving staging image
 
     ansible-playbook -i "localhost," -c local start_serving_image.yml --extra-vars "nfs_mount_point=/opt/stage image=/opt/rpi_img/stage.img"
 
 
 ## Adding a new Raspberry PI into the swarm
 This is also quite straight-forward.
  1. Assemble Raspberry PI hardware.  Connect Ethernet cable.
  2. Insert blank SD card into skia-rpi-master.
  3. `./format_new_card.yml`  Optionally add the argument `stage` for the staging environment. Type in static IP address and hostname suffix.
  4. Insert SD card into new pi.  Turn on.
 
 The SD card is partitioned to have two primary partitions and one extended partitions with 3 logical partitions.
  - `/boot` is a small primary partition that has the boot code and a key file called `cmdline.txt`.  That file is changed to mount via nfs the /root file system and boot from it.  This took a lot of tweaking to get right, and there was no authoritative source on the matter.  I had to use a few different sources and a bit of dumb luck to get the configuration just right.
  - `/tmp`, `/var`, `/home` are all logical partitions on the extended partition.  These three partitions are mounted on the SD card so the RPI can function properly and we have persistent access to logs. They are each 1G, but this can be changed if needed.
  - `/b` is a primary partition that takes up all the rest of the space.  It is used as the workspace for swarming.