Overview

These are the steps to follow in order to get the full BlackoutPedia installation running on the Raspberry Pi 3

• Basic arch linux installation
• Copy pre-populated index directory
• Configure access point
• Software installation

Prerequisites

• You have a Linux based PC that has a SD card reader
• The PC is connected to your home network
• The Raspberry Pi can be connected to the same home network by its wired eth0 interface
• You have a power supply for the Pi
• You have a Micro SD card ready with a minimum size of 64GB
• You can become root user on the PC
• Your PC has internet access
• You understand the above

Basic arch linux installation

At the time of writing I decided to use 32-bit arch linux, since it perfectly installs headless (we need no screen or keyboard connected to the Raspberry and can work with the Raspberry through ssh), it is lean and supports all aspect of the Pi's hardware that we need.

First thing is to attach the SD card to the PC and created a partition setup. The following table explains the partitions we want to setup

Partition	Type	Size	Purpose
1	W95 FAT32 (LBA)	100 MB	Boot partition
2	Linux	10 GB	Root parition for arch linux
3	Linux	Rest	Data partition, where we hold the index directory

The reason for having the third data partition is so that we can replace the arch linux installation itself independent of the data that is used by BlackoutPedia

As user root run

fdisk /dev/mmcblk0

Now create a fresh DOS partition table, by typing o

Create the first partition and set the correct type

np 1 Enter +100M
t c

Now create the remaining two paritions

np 2 Enter +10G
np 3 Enter Enter

Finally save the partitioning to the SD card by typing w

Then create the file systems on the partitions and mount the first two partitions

mkfs.vfat /dev/mmcblk0p1
mkfs.ext4 /dev/mmcblk0p2
mkfs.ext4 /dev/mmcblk0p3
mkdir boot
mkdir root
mount /dev/mmcblk0p1 boot
mount /dev/mmcblk0p2 root

Download the arch linux distribution. Make sure you use the 32-bit one, since at the time of writing, the wifi driver for the Raspberry Pi was not available for the 64-bit version. Once downloaded extract arch linux

wget http://os.archlinuxarm.org/os/ArchLinuxARM-rpi-2-latest.tar.gz
bsdtar -xpf ArchLinuxARM-rpi-2-latest.tar.gz -C root

Finally move the boot content to the boot partition and unmount everything

mv root/boot/* boot
umount boot root

Copy pre-populated index directory

Because the creation of an index for BlackoutPedia is a CPU intensive process, it is highly recommended to create such an index directory on your PC and copy over the result to the SD card directly.

This will safe a lot of time, as user root run

mkdir data
mount /dev/mmcblk0p3 data
cp -r 201708_dewiki data
umount data

Configure access point

Now take out the SD card plug it into your Pi and boot it. Make sure the Pi is connected to by wire. After a couple of seconds you can log into the Pi and run a system update. The alarm users default password is alarm and the root users default password is root. Check your home network to find out the actual IP address of the Pi (I am using 1.2.3.4 in the example below)

ssh [email protected]
su - root
pacman -Syu

Once updated you can continue with installing a package that will ease the creation of the accesspoint

pacman -S create_ap

After the installation, we create a copy of the config file that the preconfigured service is using and we will launch create_ap manually to storing our new configuration (no internet sharing, no password). Finally we start the access point and enable the service on boot

mv /etc/create_ap.conf /etc/create_ap.conf.orig
create_ap -n wlan0 BlackoutPedia --mkconfig /etc/create_ap.conf
systemctl start create_ap
systemctl enable create_ap

Software installation

This requires first of all a Java 8 installation, as root run

pacman -S jre8-openjdk-headless

Then we have to make sure the data partition is properly mounted

mkdir /data
mount /dev/mmcblk0p3 /data

And ensure it is mounted automatically after restart, by adding the following line to /etc/fstab

/dev/mmcblk0p3  /data   ext4    defaults        0       0

Now create a folder for BlackoutPedia and change the owner for the data partition

mkdir /opt/blackoutpedia
chown alarm.alarm /opt/blackoutpedia
chown -R alarm.alarm /data

And copy the JAR archive from your PC

scp blackoutpedia.jar [email protected]:/opt/blackoutpedia

From the SSH terminal with the Raspberry connection you can start BlackoutPedia for testing

java -jar /opt/blackoutpedia/blackoutpedia.jar --index /data/201708_dewiki --bind 0.0.0.0

Past that point you should be able to reach it through a Smartphone that you connect with the BlackoutPedia wifi by browsing to http://192.168.12.1:8080

Stop BlackoutPedia by hiting Ctrl+C

We now want to enable Blackoutpedia as a service that it automatically starts at boot time, so as user root create a file /etc/systemd/system/blackoutpedia.service with the following content

[Unit]
Description=BlackoutPedia service

[Install]
WantedBy=multi-user.target

[Service]
User=alarm
ExecStart=/usr/bin/java -Xms512m -Xmx512m -jar /opt/blackoutpedia/blackoutpedia.jar --index /data/201708_dewiki --bind 0.0.0.0

After the file is created you can enable the service for auto booting and start it by running

systemctl enable blackoutpedia
systemctl start blackoutpedia