Deploy an App on Pivotal Cloud Foundry Developers Console

This is the last blog of a series that showed how to deploy, configure and use the Pivotal Cloud Foundry Runtime environment and developers console.

Runtime

Developers Console

One of the cool parts of CF is the ability to install services, Hadoop, Mysql, Mongodb, and then deploy applications that attach themselves to these services. So if you wrote an analytic application you could deploy it to CF and bind it to the Hadoop service. This is all done in with automation, elasticity and dynamic tools provided by PivotalCF. Each time you deploy and app a dynamic environment is provided by CF to run the app using warden containers. Each app you push also needs a framework to run in, this is provided by buildpacks. By default PivotalCF has four system buildpacks:

Java for applications written in Java, Grails, Play, Spring or any other JVM-based language or framework
Node.js for applications written in Node or JavaScript
Rubyfor applications written in Ruby, Rack, Rails or Sinatra
Gofor applications written in Go

You can also use custom buildpacks created by the community. My good friend Matt Cowger has an example of deploying a Python Flask app using a custom build back. The basics are that during the deploy you retrieve the framework for your app from github. For this blog I'll show you how to deploy a simple "Hello World" application using the Ruby framework.

First, I'm using CentOS so I have to install Ruby on my machine:

sudo yum install ruby

sudo yum install gcc g++ make automake autoconf curl-devel openssl-devel zlib-devel httpd-devel apr-devel apr-util-devel sqlite-devel

sudo yum install ruby-rdoc ruby-devel

Once Ruby is installed I will use Gem for package building:

sudo yum install rubygems

For this app I will be using Sinatra, a DSL for quickly creating web applications in Ruby with minimal effort.

gem install bundle sinatra

Now I need to create the app. I'm logged in as the user "Jim" and have created a directory for my app in /home/jim/ruby . There are 4 files I need to create in this directoryfor this app to run

Config.ru - Contains the settings for deploying the app

require /home/jim/ruby
run Sinatra::Application

env.rb - This is the actual application

require 'rubygems'
require 'sinatra'
configure do
    disable :protection
end
get '/' do
    host = ENV['VCAP_APP_HOST']
    port = ENV['VCAP_APP_PORT']
    "<h1>Hello World!</h1><h2> I am in the Cloud! via: #{host}:#{port}</h2>"
end
get '/env' do
    res = ''
    ENV.each do |k, v|
        res << "#{k}: #{v}<br/>"
    end
    res
end

Gemfile - Contains the information on the gems used by this app

source 'https://rubygems.org'
gem 'sinatra'

manifest.yml - This file tells cf push what to do with the app. By having a manifest you dont have to enter all sorts of options when deploying, the options are contained within this file.

applications:
- name: nifty
memory: 256M
command: 'ruby env.rb'

Once these files have been created I have to create a bundle. The bundle command creates a Gemfile.lock file that contains all the versions needed to run this app

The command is simply "bundle", run at the command line in the directory containing your app.