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Update documentation regarding Ceilometer API V2

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Today, the watcher Decision Engine is not relying on Ceilometer V2 API
to query the metrics necessary for the optimization algorithm.
This patchset update the documentation to use Ceilometer API with
watcher

Change-Id: I62cf0ea7b1766b00601f3dcbbbfe20b4a9567570
This commit is contained in:
Jean-Emile DARTOIS
2015-11-27 17:31:54 +01:00
parent eb3870a4b3
commit 556368567d
2 changed files with 86 additions and 10 deletions
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62
doc/source/dev/plugins.rst
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@@ -119,3 +119,65 @@ there are no guarantees that utilizing them as is will be supported, as
they may require a set of metrics which is not yet available within the
Telemetry service. In such a case, please do make sure that you first
check/configure the latter so your new strategy can be fully functional.
Querying metrics
~~~~~~~~~~~~~~~~
The metrics available depend on the hypervisors that OpenStack manages on
the specific implementation. You can find the metrics available per hypervisor
and OpenStack release on the OpenStack site.
There are different possible ways to obtain usage metrics in Watcher, you can
use the default Ceilometer API or our Helper.
The Helper attempted to make the Ceilometer API more reusable and easy to use.
Read usage metrics using the Python binding
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
You can find the information about the Ceilometer Python binding on the
OpenStack `ceilometer client python API documentation
<http://docs.openstack.org/developer/python-ceilometerclient/api.html>`_
The first step is to authenticate against the Ceilometer service
(assuming that you already imported the Ceilometer client for Python)
with this call:
.. code-block:: py
cclient = ceilometerclient.client.get_client(VERSION, os_username=USERNAME,
os_password=PASSWORD, os_tenant_name=PROJECT_NAME, os_auth_url=AUTH_URL)
Using that you can now query the values for that specific metric:
.. code-block:: py
value_cpu = cclient.samples.list(meter_name='cpu_util', limit=10, q=query)
Read usage metrics using the Watcher Cluster History Helper
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Here below is the abstract ``BaseClusterHistory`` class of the Helper.
.. automodule:: watcher.metrics_engine.cluster_history.api
:noindex:
.. autoclass:: BaseClusterHistory
:members:
The following snippet code shows how to create a Cluster History class:
.. code-block:: py
query_history = CeilometerClusterHistory()
Using that you can now query the values for that specific metric:
.. code-block:: py
query_history.statistic_aggregation(resource_id=hypervisor.uuid,
meter_name='compute.node.cpu.percent',
period="7200",
aggregate='avg'
)