Merge "Spec: Monasca fetcher"

specs/ussuri/monasca_fetcher.rst

@@ -0,0 +1,134 @@
+..
+ This work is licensed under a Creative Commons Attribution 3.0 Unported
+ License.
+
+ http://creativecommons.org/licenses/by/3.0/legalcode
+
+=========================================
+Cloudkitty monasca fetcher implementation
+=========================================
+
+https://storyboard.openstack.org/#!/story/2006675
+
+Monasca is already supported in cloudkitty through its collector. However,
+cloudkitty lacks a dedicated fetcher for monasca, relying instead on other
+fetchers.
+
+
+Problem Description
+===================
+
+No scope discovery is available when using the monasca collector. This forces
+users to use the keystone fetcher and assign the 'rating' role to every project
+where cloudkitty is needed. Another less than ideal solution is to use the
+'source' fetcher, but that requires to specify every scope in the configuration
+file.
+
+
+Proposed Change
+===============
+
+Implementing a new fetcher using monasca to discover scopes:
+
+- The fetcher will connect to monasca and retrieve a list of scopes (dimensions
+  values in monasca) given a specified dimension name. This is achieved through
+  monasca's python client and its ``metrics.list_dimension_values()`` method.
+- The monasca endpoint will be retrieved from keystone in similar fashion to the
+  monasca collector, as it is needed for the monasca client initialization.
+  This is a good opportunity to mutualize the monasca's client bootstraping code
+  in a common file.
+
+Configuration options include:
+
+- ``dimension_name``: the monasca dimension from which the scope_ids should be
+  retrieved, defaults to ``project_id``.
+- ``monasca_tenant_id``: The monasca tenant id, has no default value.
+- ``monasca_service_name``: Name of the monasca service, defaults to ``monasca``
+- ``interface``: Endpoint type, defaults to ``internal``
+
+Alternatives
+------------
+
+None
+
+Data model impact
+-----------------
+
+None
+
+REST API impact
+---------------
+
+None
+
+Security impact
+---------------
+
+The fetcher will use the same authentication mechanism as the current
+monasca collector (keystone for authentication and python-monascaclient for
+monasca interactions), and won't introduce any new dependency.
+Thus, the new fetcher shouldn't have any security impact.
+
+Notifications Impact
+--------------------
+
+None
+
+Other end user impact
+---------------------
+
+None
+
+Performance Impact
+------------------
+
+None
+
+Other deployer impact
+---------------------
+
+None
+
+Developer impact
+----------------
+
+None
+
+Implementation
+==============
+
+Assignee(s)
+-----------
+
+Primary assignee:
+  qanglade/qanglade
+Other contributors:
+  lukapeschke/peschk_l
+
+Work Items
+----------
+
+* Implement a cloudkitty monasca scope fetcher using python-monascaclient.
+
+Dependencies
+============
+
+No new dependency is needed.
+
+Testing
+=======
+
+Regular unit tests will be included.
+
+
+Documentation Impact
+====================
+
+Documentation of the new fetcher will be added, mostly covering configuration
+of the fetcher.
+
+
+References
+==========
+
+None.