Raspberry Pi

LAMP stack

Linux - Apache - MySQL - PHP

Note: Mediawiki requires xml and mbstring packages

sudo apt-get install apache2 mysql-server php php-mysql php-xml php-mbstring

SSH Remote control

You can use remote shell to control your Raspberry Pi without directly connected mouse, keyboard and screen.

ssh pi@192.168.1.2

Ssh copy local file to remote machine

scp /path/to/local/file.zip pi@192.168.1.2:/home/pi/Downloads/file.zip

And back:

scp pi@192.168.1.2:/home/pi/Downloads/file.zip /path/to/local/file.zip

Nautilus ssh access, in the addressbar type:

ssh://pi@192.168.1.2

Ssh root access is not allowed by default but could be convenient for use with Nautilus Note: better set this back to 'no' when you are done

sudo nano /etc/ssh/sshd_config

PermitRootLogin yes

You can now access the machine as root with Nautilus, in the addressbar type:

ssh://root@192.168.1.2/

Allow ssh scripting without a password request, based on keys

You want the script to execute without it stopping to ask for a password.

• http://www.linuxproblem.org/art_9.html

Root session:

sudo -i

Generate keys, accept defaults:

ssh-keygen -t rsa

Create dir on remote:

ssh pi@192.168.1.2 mkdir -p .ssh

Add pub key to pi@192.168.1.2 authorized_keys:

cat .ssh/id_rsa.pub | ssh pi@192.168.1.2 'cat >> .ssh/authorized_keys'

Should work now without password:

ssh pi@192.168.1.2

Maybe needed, for some versions of ssh

cat .ssh/id_rsa.pub | ssh pi@192.168.1.2 'cat >> .ssh/authorized_keys2'
ssh pi@192.168.1.2 chmod 700 .ssh
ssh pi@192.168.1.2 chmod 640 .ssh/authorized_keys2

Require pi to enter password when sudo

By default the Raspbian pi user can sudo without the need to re-enter the password. If you don't like that make this change.

• https://raspberrypi.stackexchange.com/questions/57887/disable-sudo-for-user-pi-or-require-root-password

ssh pi@192.168.1.2
sudo nano /etc/sudoers.d/010_pi-nopasswd

Change it from:

pi ALL=(ALL) NOPASSWD: ALL

to

pi ALL=(ALL) ALL

VNC

For mouse and screen people.

• https://www.raspberrypi.org/documentation/remote-access/vnc/

MySql (MariaDB) Remote admin access

For example with MySql workbench:

• https://dev.mysql.com/downloads/file/?id=455790

Problem: can't connect to the server

Comment bind-address to allow access from other machines:

sudo nano /etc/mysql/mariadb.conf.d/50-server.cnf

...
#bind-address = 127.0.0.1
...

Restart database service:

sudo systemctl restart mariadb

Problem: Host '...' is not allowed to connect to this MariaDB server

Create admin user with all privileges and allow local network access.

Note: we don't use 'root' because every database has this user and everybody knows it.

Note: we allow only IP addresses starting with '192.168.1.'.

sudo -i
mysql -u root mysql -p

GRANT ALL PRIVILEGES ON *.* TO 'admin'@'192.168.1.%'
    IDENTIFIED BY '**pwd**'
    WITH GRANT OPTION;
FLUSH PRIVILEGES;
\q

Clear sql shell history:

> ~/.mysql_history

Clear bash shell history:

history -c

Performance tuning

Memory

• https://serverfault.com/questions/201075/what-tips-do-you-have-for-speeding-up-performance-of-a-mediawiki-installation

Raspberry Pi lowered GPU memory from 64 to 32 MB

CPU, Diskspace

Slim down Raspberry Pi by removing some packages ==

• https://blog.samat.org/2015/02/05/slimming-an-existing-raspbian-install/

1. Edu-related packages

apt-get -y remove --purge idle
	python3-pygame
	python-pygame
	python-tk
	idle3
	python3-tk
	python3-rpi.gpio
	python-serial
	python3-serial
	python-picamera
	python3-picamera
	python3-pygame
	python-pygame
	python-tk
	python3-tk
	debian-reference-en
	dillo
	x2x
	scratch
	nuscratch
	timidity
	smartsim
	penguinspuzzle
	pistore
	sonic-pi
	python3-numpy
	python3-pifacecommon
	python3-pifacedigitalio
	python3-pifacedigital-scratch-handler
	python-pifacecommon
	python-pifacedigitalio
	oracle-java8-jdk
	minecraft-pi
	python-minecraftpi
	wolfram-engine	
apt-get -y autoremove

Remove all packages marked 'rc'.

dpkg --list |grep "^rc" | cut -d " " -f 3 | xargs dpkg --purge