
An Introduction to boto's EC2 interface
***************************************

This tutorial focuses on the boto interface to the Elastic Compute
Cloud from Amazon Web Services.  This tutorial assumes that you have
already downloaded and installed boto.


Creating a Connection
=====================

The first step in accessing EC2 is to create a connection to the
service. There are two ways to do this in boto.  The first is:

   >>> from boto.ec2.connection import EC2Connection
   >>> conn = EC2Connection('<AWS_ACCESS_KEY_ID>', '<AWS_SECRET_ACCESS_KEY>')

At this point the variable conn will point to an EC2Connection object.
In this example, the AWS access key and AWS secret key are passed in
to the method explicitely.  Alternatively, you can set the boto config
environment variables and then call the constructor without any
arguments, like this:

   >>> conn = EC2Connection()

There is also a shortcut function in the boto package, called
connect_ec2 that may provide a slightly easier means of creating a
connection:

   >>> import boto
   >>> conn = boto.connect_ec2()

In either case, conn will point to an EC2Connection object which we
will use throughout the remainder of this tutorial.


Launching Instances
===================

Possibly, the most important and common task you'll use EC2 for is to
launch, stop and terminate instances. In its most primitive form, you
can launch an instance as follows:

   >>> conn.run_instances('<ami-image-id>')

This will launch an instance in the specified region with the default
parameters. You will not be able to SSH into this machine, as it
doesn't have a security group set. See *EC2 Security Groups* for
details on creating one.

Now, let's say that you already have a key pair, want a specific type
of instance, and you have your *security group* all setup. In this
case we can use the keyword arguments to accomplish that:

   >>> conn.run_instances(
           '<ami-image-id>',
           key_name='myKey',
           instance_type='c1.xlarge',
           security_groups=['your-security-group-here'])

The main caveat with the above call is that it is possible to request
an instance type that is not compatible with the provided AMI (for
example, the instance was created for a 64-bit instance and you choose
a m1.small instance_type). For more details on the plethora of
possible keyword parameters, be sure to check out boto's *EC2 API
reference*.


Stopping Instances
==================

Once you have your instances up and running, you might wish to shut
them down if they're not in use. Please note that this will only de-
allocate virtual hardware resources (as well as instance store
drives), but won't destroy your EBS volumes -- this means you'll pay
nominal provisioned EBS storage fees even if your instance is stopped.
To do this, you can do so as follows:

   >>> conn.stop_instances(instance_ids=['instance-id-1','instance-id-2', ...])

This will request a 'graceful' stop of each of the specified
instances. If you wish to request the equivalent of unplugging your
instance(s), simply add "force=True" keyword argument to the call
above. Please note that stop instance is not allowed with Spot
instances.


Terminating Instances
=====================

Once you are completely done with your instance and wish to surrender
both virtual hardware, root EBS volume and all other underlying
components you can request instance termination. To do so you can use
the call bellow:

   >>> conn.terminate_instances(instance_ids=['instance-id-1','instance-id-2', ...])

Please use with care since once you request termination for an
instance there is no turning back.
