Cloudy Release (with a chance of sunshine)

Cloudy Release is a system for deploying applications.

It tries to solve these common problems:

• how do I keep nodes that were offline during the last deployment up-to-date?
• how can I make sure the deployment went well?
• how do I deploy my app on multiple nodes with different configurations?

Cloudy Release tries to answer these problems simply:

• clients are installed on the hosts where the applications are deployed. They regularly poll the server and deploy updates when necessary. If a host goes down when an update is triggered, it will catch up on its next reboot;
• the web interface gives an overview to check deployment details;
• projects can have different deployment configurations, each with their set of deployment variables (think of Saltstack's pillars). For example a website could have production and testing deployments, with different database settings. The deployment scripts can then retrieve these variables and use them as they want.

Compared to Fabric, deployments are faster because deployment scripts are run locally by the clients, you have a place to check if something went wrong with your deployments, and you can write template deployment scripts driven by configuration (you can do this to some extent with Fabric using roles, but roles are tied to hosts, you can't deploy production + testing variants of your site on the same host without ugly hacks).

Installation example

Here is an example for serving the Cloudy Release server with nginx, postgresql, uwsgi+gevent and supervisor.

Install system dependencies ():

sudo apt-get install build-essential libpq-dev python-dev nginx \
    postgresql supervisor python-pip python-virtualenv

Create a PostgreSQL database for the site:

sudo su postgres
createdb -E utf8 -O cloudy cloudy
exit

Create an user for the running the site:

adduser cloudy
sudo su cloudy
cd /home/cloudy

Create a virtualenv:

virtualenv venv
source venv/bin/activate

Create a directory for holding static files:

mkdir static

Clone the repository and checkout the develop branch:

git clone https://github.com/flupke/cloudy-release.git
cd cloudy-release
git checkout develop

Install requirements (in this example we are going to serve the site with uWSGI and gevent):

pip install -r requirements.txt
pip install gevent uwsgi psycogreen

Initialize database:

./manage.py syncdb
./manage.py migrate

Put local settings in cloudy/settings/local.py:

DEBUG = False
TEMPLATE_DEBUG = False
STATIC_ROOT = '/home/cloudy/static'
ALLOWED_HOSTS = ['cloudy.example.com']

Create a nginx configuration in /etc/nginx/sites-enables/cloudy.example.com:

server {
    listen 80;
    server_name cloudy.example.com;

    location /static {
        alias /home/cloudy/static;
    }

    location / {
        uwsgi_pass unix:///tmp/cloudy.sock;
        include uwsgi_params;
    }
}

Create a supervisord configuration file in /etc/supervisor/conf.d/cloudy.conf:

[program:cloudy]
command=/home/cloudy/venv/bin/uwsgi
    --module cloudy.wsgi:application
    --env DJANGO_SETTINGS_MODULE=cloudy.settings
    --master
    --pidfile=/tmp/cloudy.pid
    --socket /tmp/cloudy.sock
    --chmod-socket=666
    --disable-logging
    --processes 2
    --gevent 64
user = cloudy
group = cloudy
autostart = true
autorestart = true
redirect_stderr = true
directory = /home/cloudy/cloudy-release
stopsignal = QUIT
stopwaitsecs = 10

And finally start the site's process:

sudo supervisorctl update

If all went well the site should be available on http://cloudy.example.com.