Programatically defined infrastructure for the cloud
http://ajdiaz.me/doc/2013/03141-programatically-defined-infrastructure.txt
Version: 2013-03-14


With the rise of cloud computing there are also new paradigms in order to
provision hosts as fast as possible. In this scenario some utilities like
Puppet or Chef are the most popular ones. But though the utility of that
applications is well known, they only cover the OS point of view provission,
but forget completely the infrastructure behind that.

The idea of this paper is to use a program language to define a
infrastructure running in the cloud. For that we need to create high level
funtions which allow us to create resources easily, and offer a way to
provision them.

For example, let's suppose the following code in python (any other language
could be used here):

import infrastructure as i

try:
  instance = i.create_instance(instance_type="m1.small"):
  volume = i.create_volume(size=20)
  instance.attach_volume(volume, '/dev/xvdf')
except InstanceError as e:
  print("Unable to create instance: {}".format(str(e)))
except VolumeError as e:
  print("Unable to create volume: {}".format(str(e)))
except AttachmentError as e:
  print("Unable to attach volume: {}".format(str(e)))

This code create a new instance and new volume, and attach the volume to the
instance, catching the errors produced in the process. This piece of code is
easy to iterate, or even to be included in higher-level function or class
and built more complex structures, defined for each infrastructure in
a custom way.

At the end, we can do something like this:

x = Infrastructure()

if x.deploy():
  x.provision()