The first thing to do is pass in your credentials and instantiate a Rackspace client:

    <?php

    require 'vendor/autoload.php';

    use OpenCloud\Rackspace;

    $client = new Rackspace(Rackspace::US_IDENTITY_ENDPOINT, array(
      'username' => '{username}',
      'apiKey'   => '{apiKey}',
    ));

Now, set up the Auto Scale service:

    $service = $client->computeService('{catalogName}', '{region}', '{urlType}');

`{catalogName}` is the name of the service, as it appears in the service catalog. For Rackspace users, a default will be provided if you pass `null` in for this argument. For OpenStack users, you cannot do this: you must instead set your own value since it can depend on your environment setup.

`{region}` is the Compute region the service will operate in. For Rackspace users, you can select one of the following from the supported regions page.

`{urlType}` is the type of URL to use, depending on what endpoints your catalog provides. For Rackspace, you may use either `internalURL` or `publicURL`. The former will execute HTTP transactions over the internal network configured for your service, possibly reducing latency and the overall bandwidth cost - the caveat is that all of your resources must be in same region. `publicURL`, however, which is the default, will operate over the public Internet and is to be used for multi-region installations.