World's Smallest IaaS, Part 4: Hello World

In this blog post we deploy a simple “hello world” app to our Cloud Foundry installation.

[2014-10-19 this blog post has been updated to reflect Cloud Foundry CLI version 6.6.1]

Pre-requisites

We have already set up Cloud Foundry:

1. World’s Smallest IaaS, Part 1 describes installing VMware ESXi and VMware vCenter on an Apple Mac Pro
2. World’s Smallest IaaS, Part 2 describes installing Cloud Foundry’s Ops Manager and deploying BOSH to the ESXi/vCenter
3. World’s Smallest IaaS, Part 3: the PaaS describes installing Elastic Runtime (i.e. Cloud Foundry)

Install Cloud Foundry CLI

Click here ^[1] to browse to the Cloud Foundry CLI homepage’s download section. Choose the Mac OS X 64 bit (Stable installer). Double-click the downloaded file to install the CLI.

Test for a successful install by bringing up a terminal and querying the version of the CLI: ^[2]

cf --version
  cf version 6.6.1-b2cdb2b-2014-09-23T23:07:17+00:00

Let’s point the CLI to our installation:

cf api --skip-ssl-validation api.cf.nono.com

Let’s log in. We’ll use the UAA admin credentials (these credentials can be retrieved from Ops Manager; here is a description of how to retrieve the credentials). We’ll target the “CF Engineering” organization, which we created at the end of Part 3:

cf login -u admin -p a723936f2102e4xxxxxx # Use admin login
  API endpoint: https://api.cf.nono.com
  Authenticating...
  OK

  Select an org (or press enter to skip):
  1. system
  2. CF Engineering

  Org> 2
  Targeted org CF Engineering

  Targeted space development



  API endpoint:   https://api.cf.nono.com (API version: 2.13.0)
  User:           admin
  Org:            CF Engineering
  Space:          development

Hello World

Let’s create our first app, a simple app, a “hello world” app. Let’s create a directory where we’ll do our work:

mkdir -p ~/workspace/hello-world
cd ~/workspace/hello-world

Create a file, Gemfile, with the following contents (a Gemfile is a file that describes the Ruby libraries (i.e. “gems”) upon which your application depends). The gem we’re using, Sinatra, is a Ruby-based webserver (though its authors may argue that it’s a DSL (domain specific language) for creating web applications in Ruby).

# Gemfile
source "http://rubygems.org"
gem "sinatra"

Now let’s write a very simple Ruby/Sinatra program, hello.rb:

# hello.rb
require 'sinatra'
get '/' do
  "hello worldn"
end

Next we create config.ru, a file which is a configuration file for Rack-based applications (or, in this case, Sinatra, which is a Rack-based web framework):

# config.ru
require './hello'
run Sinatra::Application

Let’s make sure we’ve installed Bundler (sudo is not necessary if you’re using rvm, rbenv, or chruby) (if unsure, use sudo):

sudo gem install bundler
bundle

Now let’s push:

cf push hello-world
  Creating app hello-world in org CF Engineering / space development as admin...
  OK

  Creating route hello-world.cf.nono.com...
  OK

  Binding hello-world.cf.nono.com to hello-world...
  OK

  Uploading hello-world...
  Uploading app files from: /Users/cunnie/workspace/hello-world
  Uploading 892, 4 files
  OK

  Starting app hello-world in org CF Engineering / space development as admin...
  OK
  -----> Downloaded app package (4.0K)
  -----> Compiling Ruby/Rack
  -----> Using Ruby version: ruby-2.0.0
  -----> Installing dependencies using 1.6.3
         Running: bundle install --without development:test --path vendor/bundle --binstubs vendor/bundle/bin -j4 --deployment
         Fetching gem metadata from http://rubygems.org/..........
         Using bundler 1.6.3
         Installing tilt 1.4.1
         Installing rack 1.5.2
         Installing rack-protection 1.5.3
         Installing sinatra 1.4.5
         Your bundle is complete!
         Gems in the groups development and test were not installed.
         It was installed into ./vendor/bundle
         Bundle completed (4.41s)
         Cleaning up the bundler cache.
  ###### WARNING:
         You have not declared a Ruby version in your Gemfile.
         To set your Ruby version add this line to your Gemfile:
         ruby '2.0.0'
         # See https://devcenter.heroku.com/articles/ruby-versions for more information.
  ###### WARNING:
         No Procfile detected, using the default web server (webrick)
         https://devcenter.heroku.com/articles/ruby-default-web-server

  -----> Uploading droplet (13M)

  1 of 1 instances running

  App started

  Showing health and status for app hello-world in org CF Engineering / space development as admin...
  OK

  requested state: started
  instances: 1/1
  usage: 1G x 1 instances
  urls: hello-world.cf.nono.com

       state     since                    cpu    memory        disk
  #0   running   2014-10-19 12:57:21 PM   0.0%   34.4M of 1G   45M of 1G

Now we test: let’s browse to https://hello-world.cf.nono.com/:

The output of our “hello world” application. Plain, minimal formatting, but functional

We have successfully tested our Cloud Foundry installation by installing our first app, which is merely a hint of things to come.

Acknowledgements

The ‘hello world’ example was pulled from internal Cloud Foundry documentation.

Footnotes

¹ For those of you lucky enough to have Homebrew-cask installed, you can use it to install the Cloud Foundry CLI: brew cask install cloudfoundry-cli.

² If you see command not found, then /usr/local/bin is unlikely to be in your PATH. A simple workaround is to invoke the CLI by typing /usr/local/bin/cf rather than cf.

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