[occi-wg] Semantics of OCCI API: nouns and verbs

Richard Davies richard.davies at elastichosts.com
Thu Apr 16 11:16:07 CDT 2009

> list, info, create, destroy, set are equivalent to CRUD;

Let me raise an additional point of detail here, specifically on the
(R)etrieve operation.

At present, the API draft specifies a single central entry point, on which a
HTTP GET returns a complete description of all objects that a user has
access to.

For a user with a large number of servers, this could be a very expensive
operation - the cloud will have to check with each individual virtualization
host to get values such as the performance monitoring.

It is probably good to offer this option, but the API should definitely
ofter separate 'retrieve' operations (which are much cheaper) such as:

- List UUIDs of all a user's objects, but do not describe them fully
- Describe a single object fully given its UUID.

At ElasticHosts, we provide all of these varieties of retrieve via:

/guests/list - list all UUIDs without fully descriptions
/guests/UUID/info - describe a single object fully
/guests/info - describe all objects fully

I think that the standard API needs to offer similar capabilities

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