Merge "Clarify the Glance/metadefs relationship"

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Zuul 2019-03-11 15:00:58 +00:00 committed by Gerrit Code Review
commit 3ba6b40c27
1 changed files with 25 additions and 1 deletions

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@ -23,7 +23,10 @@ About Glance
The Image service (glance) project provides a service where users can upload
and discover data assets that are meant to be used with other services.
This currently includes images and metadata definitions.
This currently includes *images* and *metadata definitions*.
Images
------
Glance image services include discovering, registering, and
retrieving virtual machine (VM) images. Glance has a RESTful API that allows
@ -35,6 +38,27 @@ VM images made available through Glance can be stored in a variety of
locations from simple filesystems to object-storage systems like the
OpenStack Swift project.
Metadata Definitions
--------------------
Glance hosts a *metadefs* catalog. This provides the OpenStack community
with a way to programmatically determine various metadata key names and
valid values that can be applied to OpenStack resources.
Note that what we're talking about here is simply a *catalog*; the keys and
values don't actually do anything unless they are applied to individual
OpenStack resources using the APIs or client tools provided by the services
responsible for those resources.
It's also worth noting that there is no special relationship between the
Image Service and the Metadefs Service. If you want to apply the keys and
values defined in the Metadefs Service to images, you must use the Image
Service API or client tools just as you would for any other OpenStack
service.
Design Principles
-----------------
Glance, as with all OpenStack projects, is written with the following design
guidelines in mind: