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Metadata Definitions Service API v2 (CURRENT)
Metadefs
General information
The Metadata Definitions Service ("metadefs", for short) provides a common API for vendors, operators, administrators, services, and users to meaningfully define available key:value pairs that can be used on different types of cloud resources (for example, images, artifacts, volumes, flavors, aggregates, and other resources).
To get you started, Glance contains a default catalog of metadefs that may be installed at your site; see the README in the code repository for details.
Once a common catalog of metadata definitions has been created, the catalog is available for querying through the API. Note that this service stores only the catalog, because metadefs are meta-metadata. Metadefs provide information about resource metadata, but do not themselves serve as actual metadata.
Actual key:value pairs are stored on the resources to which they apply using the metadata facilities provided by the appropriate API. (For example, the Images API would be used to put specific key:value pairs on a virtual machine image.)
A metadefs definition includes a property's key, its description, its constraints, and the resource types to which it can be associated. See Metadata Definition Concepts in the Glance Developer documentation for more information.
Note
By default, only admins can manipulate the data exposed by this API, but all users may list and show public resources. This changed from a default of "open to all" in the Wallaby release.