
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. The recommended way of doing this in boto is:

   >>> import boto.ec2
   >>> conn = boto.ec2.connect_to_region("us-west-2",
   ...    aws_access_key_id='<aws access key>',
   ...    aws_secret_access_key='<aws secret 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 explicitly.  Alternatively, you can set the
boto config environment variables and then simply specify which region
you want as follows:

   >>> conn = boto.ec2.connect_to_region("us-west-2")

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.


Checking What Instances Are Running
===================================

You can also get information on your currently running instances:

   >>> reservations = conn.get_all_reservations()
   >>> reservations
   [Reservation:r-00000000]

A reservation corresponds to a command to start instances. You can see
what instances are associated with a reservation:

   >>> instances = reservations[0].instances
   >>> instances
   [Instance:i-00000000]

An instance object allows you get more meta-data available about the
instance:

   >>> inst = instances[0]
   >>> inst.instance_type
   u'c1.xlarge'
   >>> inst.placement
   u'us-west-2'

In this case, we can see that our instance is a c1.xlarge instance in
the *us-west-2* availability zone.


Using Elastic Block Storage (EBS)
*********************************


EBS Basics
==========

EBS can be used by EC2 instances for permanent storage. Note that EBS
volumes must be in the same availability zone as the EC2 instance you
wish to attach it to.

To actually create a volume you will need to specify a few details.
The following example will create a 50GB EBS in one of the *us-west-2*
availability zones:

   >>> vol = conn.create_volume(50, "us-west-2")
   >>> vol
   Volume:vol-00000000

You can check that the volume is now ready and available:

   >>> curr_vol = conn.get_all_volumes([vol.id])[0]
   >>> curr_vol.status
   u'available'
   >>> curr_vol.zone
   u'us-west-2'

We can now attach this volume to the EC2 instance we created earlier,
making it available as a new device:

   >>> conn.attach_volume (vol.id, inst.id, "/dev/sdx")
   u'attaching'

You will now have a new volume attached to your instance. Note that
with some Linux kernels, */dev/sdx* may get translated to */dev/xvdx*.
This device can now be used as a normal block device within Linux.


Working With Snapshots
======================

Snapshots allow you to make point-in-time snapshots of an EBS volume
for future recovery. Snapshots allow you to create incremental
backups, and can also be used to instantiate multiple new volumes.
Snapshots can also be used to move EBS volumes across availability
zones or making backups to S3.

Creating a snapshot is easy:

   >>> snapshot = conn.create_snapshot(vol.id, 'My snapshot')
   >>> snapshot
   Snapshot:snap-00000000

Once you have a snapshot, you can create a new volume from it. Volumes
are created lazily from snapshots, which means you can start using
such a volume straight away:

   >>> new_vol = snapshot.create_volume('us-west-2')
   >>> conn.attach_volume (new_vol.id, inst.id, "/dev/sdy")
   u'attaching'

If you no longer need a snapshot, you can also easily delete it:

   >>> conn.delete_snapshot(snapshot.id)
   True


Working With Launch Configurations
==================================

Launch Configurations allow you to create a re-usable set of
properties for an instance.  These are used with AutoScaling groups to
produce consistent repeatable instances sets.

Creating a Launch Configuration is easy:

>>> conn = boto.connect_autoscale()
>>> config = LaunchConfig(name='foo', image_id='ami-abcd1234', key_name='foo.pem')
>>> conn.create_launch_configuration(config)

Once you have a launch configuration, you can list you current
configurations:

>>> conn = boto.connect_autoscale()
>>> config = conn.get_all_launch_configurations(names=['foo'])

If you no longer need a launch configuration, you can delete it:

>>> conn = boto.connect_autoscale()
>>> conn.delete_launch_configuration('foo')

Changed in version 2.27.0.

Note: If "use_block_device_types=True" is passed to the connection it will
  deserialize Launch Configurations with Block Device Mappings into a
  re-usable format with BlockDeviceType objects, similar to how AMIs
  are deserialized currently.  Legacy behavior is to put them into a
  format that is incompatabile with creating new Launch
  Configurations. This switch is in place to preserve backwards
  compatability, but its usage is the preferred format going
  forward.If you would like to use the new format, you should use
  something like:

  >>> conn = boto.connect_autoscale(use_block_device_types=True)
  >>> config = conn.get_all_launch_configurations(names=['foo'])
