Cloud Block Storage and APIs¶

When you begin writing your own software to interact with Cloud Block Storage, you might want to learn about how Cloud Block Storage works in the Cloud Control Panel and how APIs are documented at Rackspace.

Cloud Block Storage API investigation¶

Using an API, you can write software to automate functions that could otherwise be performed manually by a person logged in to the Cloud Control Panel. You can accelerate your understanding of how the API works by using the Cloud Control Panel to demonstrate the manual process before you begin to automate it; to interact with the Cloud Block Storage service, the Cloud Control Panel sends requests via the same API that you interact with when you write your own software.

Sometimes, especially for new features that are not yet available in the Cloud Control Panel, you can write software to perform functions using the API that could not be performed in any other way. Product announcements for Limited Availability and Early Access releases point out this limitation when it applies. In that case, experimenting in the Cloud Control Panel can show you only part of the process of working with a new feature; other details are described in the API documentation.

Just as you can use the Cloud Control Panel to help you understand a manual process that you intend to automate, you can use the API documentation to help you understand how to use API operations to automate cloud functions.

The API documentation describes what you can accomplish, how to structure an API operation, and what responses to expect.

Cloud Block Storage API demonstration¶

Using the process suggested at Cloud Block Storage API investigation, this section provides an example of how you can plan and then write your own software to perform one simple task: list all your Cloud Block Storage volumes.

Learn about Cloud Block Storage in the Cloud Control Panel¶

When you login to the Cloud Control Panel, your session begins with information about your Cloud Servers. To see your Cloud Block Storage information, click Storage and then click Block Storage Volumes.

To move from Cloud Servers to Cloud Block Storage details, click Storage and then click Block Storage Volumes. — *To move from Cloud Servers to Cloud Block Storage details, click “Storage” and then click “Block Storage Volumes”.*¶

By default, the list is focused on your account’s home region, showing all volumes in that region; you can select a different region and you can search for a specific volume.

*If you have no Cloud Block Storage volumes, the Cloud Control Panel shows you how to create one.*¶

If your list of volumes is not empty, then for each volume you can see:

Its ID
The name of the server to which it is attached
The region in which it is located
The type of disk it uses
Its size

*The Cloud Control Panel lists all of your Cloud Block Storage volumes.*¶

Note

Because the Cloud Control Panel uses APIs, watching the Cloud Control Panel work can help you learn how to work with APIs.

To see how the Cloud Control Panel gets its information:

Launch the Chrome browser.
In Chrome, log in to your Cloud Control Panel account.
For Mac, from the Chrome menu, select View > Developer > Developer Tools. For Windows, from the Chrome menu, select More tools > Developer Tools.
Experiment in the Cloud Control Panel and observe the actions in Chrome’s developer view.

You can use Chrome's developer tools to observe the Cloud Control Panel's API interactions. — *You can use Chrome’s developer tools to observe the Cloud Control Panel’s API interactions.*¶

Learn about Cloud Block Storage in API documentation¶

In the API documentation, you can see all available API operations for all cloud services. The operations are grouped according to the service they interact with (for example, Cloud Block Storage or Cloud Files) and the scope they act on (for example, volumes or snapshots).

You can see all Cloud Block Storage operations in the Cloud Block Storage API Reference. In the group of Volumes operations, you can see that:

Sending a POST request to the v1/{tenant_id}/volumes URI requests creation of a new server
Sending a GET request to the same URI requests a basic list of information about volumes
Sending a GET request to the same URI and appending /detail requests an expanded list of information about volumes

On the first GET line, click detail to see more about how the API handles this request. The request parameters and sample response shown here can help you formulate a basic List volumes request to the API and understand the API’s response.

In the sample response, id, display_name, size, and volume_type correspond to the information available on the Cloud Control Panel.

In the Getting Started Guide for the Cloud Block Storage API, you can see an example with the cURL command-line interface (CLI) for Listing existing block storage volumes.