6. Installation steps

The following steps describe the installation of PyScaler on a Centos 6 box.

• Install EPEL repository

  rpm -Uvh http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm

• Install required packages

  yum install httpd mod_wsgi tomcat6-webapps tomcat6 python-pip librabbitmq \
  rabbitmq-server.noarch make gcc gcc-c++ java-1.6.0-openjdk-devel \
  java-1.6.0-openjdk git sqlite memcached nginx

• Enable and start services

  chkconfig memcached on
  /etc/init.d/memcached start
  chkconfig rabbitmq-server on
  /etc/init.d/rabbitmq-server

• Install the virtualenv packages to ease the python libraries management

  pip-python install virtualenv
  pip-python install virtualenvwrapper

• Create a new virtualenv

  mkvirtualenv pyscaler

• Create the pyscaler folder

  mkdir -p /opt/django/pyscaler
  

• Create the celery logs folder

  mkdir /var/log/celery
  chown pyscaler:pyscaler  /var/log/celery
  mkdir /var/run/celery
  chown pyscaler:pyscaler  /var/run/celery

• Grab the latest PyScaler version from github

cd /opt/django/pyscaler
git clone https://www.github.com/madrover/pyscaler.git

• Jpype python lib needs Java JDK to be installed and have JAVA_HOME defined to build correctly. More details here.

  export JAVA_HOME=/usr/lib/jvm/java-1.6.0-openjdk.x86_64/

• Install pyscaler python lib requirements

pip install -r requirements.txt

• Configure Nginx to forward requests to Django / Gunicorn. There is a good guide here.

  This is an example nginx configuration

upstream app_server_djangoapp {
    server localhost:8000 fail_timeout=0;
}

server {
    listen 80;
    server_name pyscaler;

    access_log  /var/log/nginx/guni-access.log;
    error_log  /var/log/nginx/guni-error.log info;

    keepalive_timeout 5;

    root /opt/django/pyscaler/pyscaler;

    location /static {
        autoindex on;
        alias/opt/django/pyscaler/pyscaler/site_media/static;
    }

    location /media {
       autoindex on;
       alias /opt/django/pyscaler/pyscaler/site_media/media;
    }

    location / {
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $http_host;
        proxy_redirect off;

        if (!-f $request_filename) {
            proxy_pass http://app_server_djangoapp;
            break;
        }
    }
}