OpenStack Object Storage is an object-based storage system that stores content and metadata as objects. You create, modify, and get objects and metadata by using the Object Storage API, which is implemented as a set of Representational State Transfer (REST) web services.
For an introduction to OpenStack Object Storage, see Object Storage in the OpenStack Cloud Administrator Guide.
You use the HTTPS (SSL) protocol to interact with Object Storage, and you use standard HTTP calls to perform API operations. You can also use language-specific APIs, which use the RESTful API, that make it easier for you to integrate into your applications.
To assert your right to access and change data in an account, you identify yourself to Object Storage by using an authentication token. To get a token, you present your credentials to an authentication service. The authentication service returns a token and the URL for the account. Depending on which authentication service that you use, the URL for the account appears in:
OpenStack Identity Service. The URL is defined in the service catalog.
Tempauth. The URL is provided in the
X-Storage-Urlresponse header.
In both cases, the URL is the full URL and includes the account resource. For information about authentication, see the section called “Authentication”.
The Object Storage API supports the standard, non-serialized response format, which is the default, and both JSON and XML serialized response formats. See the section called “Serialized response formats”.
The Object Storage system organizes data in a hierarchy, as follows:
Account. Represents the top-level of the hierarchy.
Your service provider creates your account and you own all resources in that account. The account defines a namespace for containers. A container might have the same name in two different accounts.
In the OpenStack environment, account is synonymous with a project or tenant.
Container. Defines a namespace for objects. An object with the same name in two different containers represents two different objects. You can create any number of containers within an account.
In addition to containing objects, you can also use the container to control access to objects by using an access control list (ACL). You cannot store an ACL with individual objects.
In addition, you configure and control many other features, such as object versioning, at the container level. See the section called “Object versioning”.
You can bulk-delete up to 10,000 containers in a single request. See the section called “Bulk delete”.
Object. Stores data content, such as documents, images, and so on. You can also store custom metadata with an object.
With the Object Storage API, you can:
Store an unlimited number of objects. Each object can be as large as 5 GB, which is the default. You can configure the maximum object size.
Upload and store objects of any size with large object creation. See the section called “Large objects”.
Use cross-origin resource sharing to manage object security. See the section called “Assign CORS headers to requests”.
Compress files. See the section called “Use Content-Encoding metadata”.
Override browser behavior for an object. See the section called “Use the Content-Disposition metadata”.
Schedule objects for deletion. See the section called “Schedule objects for deletion”.
Bulk-delete up to 10,000 objects in a single request. See the section called “Bulk delete”.
Auto-extract archive files. See the section called “Auto-extract archive files”.
Generate a URL that provides time-limited GET access to an object. See the section called “Temporary URL middleware”.
Upload objects directly to the Object Storage system from a browser by using form POST middleware. See the section called “Form POST middleware”.
The account, container, and object hierarchy affects the way you interact with the Object Storage API.
Specifically, the resource path reflects this structure and has this format:
/v1/{account}/{container}/{object}For example, for the flowers/rose.jpg
object in the images container in the
12345678912345 account, the resource
path is:
/v1/12345678912345/images/flowers/rose.jpg
Notice that the object name contains the
/ character. This slash does not
indicate that Object Storage has a sub-hierarchy called
flowers because containers do not store
objects in actual sub-folders. However, the inclusion of
/ or a similar convention inside object
names enables you to create pseudo-hierarchical folders and
directories. See the section called “Pseudo-hierarchical folders and directories”.
For example, if the endpoint for Object Storage is
objects.mycloud.com, the returned URL
is
https://objects.mycloud.com/v1/12345678912345.
To access a container, append the container name to the resource path.
To access an object, append the container and the object name to the path.
If you have a large number of containers or objects, you can
use query parameters to page through large lists of
containers or objects. Use the marker,
limit, and
end_marker query parameters to
control how many items are returned in a list and where the
list starts or ends. See the section called “Page through large lists of containers or objects”.
Object Storage HTTP requests have the following default constraints. Your service provider might use different default values.
| Item | Maximum value | Notes |
|---|---|---|
| Number of HTTP headers | 90 | |
| Length of HTTP headers | 4096 bytes | |
| Length per HTTP request line | 8192 bytes | |
| Length of HTTP request | 5 GB | |
| Length of container names | 256 bytes | Cannot contain the /
character. |
| Length of object names | 1024 bytes | By default, there are no character restrictions. |
You must UTF-8-encode and then URL-encode container and object names before you call the API binding. If you use an API binding that performs the URL-encoding for you, do not URL-encode the names before you call the API binding. Otherwise, you double-encode these names. Check the length restrictions against the URL-encoded string.
These sections describe the operations that you can perform with the Object Storage API:
the section called “Accounts”. Use to perform account-level tasks.
Lists containers for a specified account. Creates, updates, and deletes account metadata. Shows account metadata.
the section called “Containers”. Use to perform container-level tasks.
Lists objects in a specified container. Creates, shows details for, and deletes containers. Creates, updates, shows, and deletes container metadata.
the section called “Objects”. Use to perform object-level tasks.
Creates, replaces, shows details for, and deletes objects. Copies objects with another object with a new or different name. Updates object metadata.
