SBHS Server

SBHS Virtual Labs Website

This branch contains the server code for the load sharing architecture. It consists of a master server, connected to several Raspberry Pis, each of which is connected to four SBHS devices.

Please follow the steps below to set up the server code on your system:

• Clone this repository.
  git clone https://github.com/sbhs-iitb/sbhs.git
  If you have permission issues, make sure that you are added as a collaborator. Contact rupakrokade@gmail.com

• Make sure you are on branch master.
  Type git branch to check your current branch.
  To switch to a specific branch, type git checkout <branchname>

• Install pip and virtualenv. These two packages need to be installed globally on your system.

• Setup a virtualenv with the following command.
  virtualenv venv
  Make sure you are using Python 2.7.

• Activate the virtualenv with source venv/bin/activate

• Go into the project directory and install the dependencies.

cd sbhs/
pip install -r requirements.txt

• Install the following packages

sudo apt-get install curl

• Create and run the database migrations using the following commands

python manage.py makemigrations
python manage.py migrate

• Grant permissions to the serial ports
  sudo chmod 666 /dev/ttyUSB*

• Copy the file credentials.py.example to credentials.py
  cp sbhs_server/credentials.py.example sbhs_server/credentials.py
  Open the file credentials.py in your favourite editor.
  Set the variables accordingly. You will need the DB_* variables if you're using MySQL.
  NOTE : Whenever you're adding/removing/renaming any variable names in credentials.py, please update credentials.py.example accordingly.

• The IP addresses of all the connected Raspberry Pis must be entered into the file sbhs_server/RPi_data/ipaddrs.txt. Make sure that each IP address is entered on a separate line.

• Set up passwordless ssh access to each of the Raspberry Pis. This is required to copy the log files and get the health report from the Raspberry Pis during the hourly cronjob.

ssh-keygen -t rsa
ssh-copy-id pi@XX.XXX.X.XXX

The ssh-keygen command needs to be run only once. But you need to run ssh-copy-id for each of the Raspberry Pis. (You can write a simple script do that, getting the IPs from the file sbhs_server/RPi_data/ipaddrs.txt)

• Make sure the Raspberry Pis are set up. For instructions on how to set up the Raspberry Pis, click here. Run the cronjob on each of the Raspberry Pis.

bash cron_job.sh

• Run the script new_cron_job.sh on the master server.

bash new_cron_job.sh

• Add the cronjob to crontab.
  Open crontab with crontab -e
  Add the line 59 * * * * bash /path/to/your/project/root/new_cron_job.sh

• Run the server with python manage.py runserver. Open localhost:8000 in your browser.

Instructions for setting up MySQL

• Install the following packages

sudo apt-get install libmysqlclient-dev
sudo apt-get install mysql-server

• Run mysql secure installation and disallow remote root login.(Highly recommended for security purposes)

• Create a new user in MySQL with the following command.

CREATE USER 'sbhs_pi'@'10.102.7.%' IDENTIFIED BY 'password'
GRANT SELECT, INSERT, DELETE, UPDATE ON sbhs.* TO 'sbhs_pi'@'10.102.7.%'

Here, 10.102.7.* is the subnet address which will contain all the Raspberry Pis. Modify it according to your own network.

Instructions for setting up Apache

• Make sure you have Apache 2.4 installed on your system.

• Install the mod-wsgi module.
  sudo apt-get install libapache2-mod-wsgi

• Enable the module (If not enabled already)
  sudo a2enmod wsgi

• Enable the modules proxy and proxy_http. These are required to proxy pass certain incoming requests to the Raspberry Pis.

sudo a2enmod proxy
sudo a2enmod proxy_http

• Open the file index.wsgi in your favourite editor.
  Set the variable path_to_venv as the absolute path to your virtualenv
  Set the variable path_to_project_root as the absolute path to your project root directory.
  Note the trailing slashes in both the path names
• Copy the file apache.conf to the sites-available directory. sudo cp apache.conf /etc/apache2/sites-available/002-sbhs.conf
• Change the variables python-path and python-home to point to your sbhs_server directory and your venv respectively.
• Change the path to your index.wsgi accordingly.
• Once you're done with all this, enable this site and disable the existing default site.

sudo a2dissite 000-default.conf
sudo service apache2 reload
sudo a2ensite 002-sbhs.conf
sudo service apache2 reload
sudo service apache2 restart

• Chown the entire project to set www-data as the group.
  sudo chown -R yourusername:www-data sbhs/

• Apache needs write permissions to the log and experiments directory.

mkdir -p log experiments
touch log/django-error.log
sudo chmod -R 775 log experiments

• Reload Apache. Your site should be live now at localhost/sbhs