c68d33f341
In watcher/metrics_engine/cluster_history/api.py, we can find the BaseClusterHistory abstract base class. To follow the same naming convention observed throughout the rest of the project, I renamed watcher/metrics_engine/cluster_history/api.py to watcher/metrics_engine/cluster_history/base.py Change-Id: If18f8db7f0982e47c1998a469c54952670c262f5 Closes-Bug: #1548398
120 lines
4.9 KiB
Python
120 lines
4.9 KiB
Python
# -*- encoding: utf-8 -*-
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# Copyright (c) 2015 b<>com
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#
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# Authors: Jean-Emile DARTOIS <jean-emile.dartois@b-com.com>
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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# implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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"""
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A :ref:`Cluster Data Model <cluster_data_model_definition>` is a logical
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representation of the current state and topology of the
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:ref:`Cluster <cluster_definition>`
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:ref:`Managed resources <managed_resource_definition>`.
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It is represented as a set of
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:ref:`Managed resources <managed_resource_definition>`
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(which may be a simple tree or a flat list of key-value pairs)
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which enables Watcher :ref:`Strategies <strategy_definition>` to know the
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current relationships between the different
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:ref:`resources <managed_resource_definition>`) of the
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:ref:`Cluster <cluster_definition>` during an :ref:`Audit <audit_definition>`
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and enables the :ref:`Strategy <strategy_definition>` to request information
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such as:
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- What compute nodes are in a given
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:ref:`Availability Zone <availability_zone_definition>`
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or a given :ref:`Host Aggregate <host_aggregates_definition>` ?
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- What :ref:`Instances <instance_definition>` are hosted on a given compute
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node ?
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- What is the current load of a compute node ?
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- What is the current free memory of a compute node ?
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- What is the network link between two compute nodes ?
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- What is the available bandwidth on a given network link ?
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- What is the current space available on a given virtual disk of a given
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:ref:`Instance <instance_definition>` ?
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- What is the current state of a given :ref:`Instance <instance_definition>`?
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- ...
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In a word, this data model enables the :ref:`Strategy <strategy_definition>`
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to know:
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- the current topology of the :ref:`Cluster <cluster_definition>`
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- the current capacity for each
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:ref:`Managed resource <managed_resource_definition>`
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- the current amount of used/free space for each
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:ref:`Managed resource <managed_resource_definition>`
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- the current state of each
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:ref:`Managed resources <managed_resource_definition>`
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In the Watcher project, we aim at providing a generic and very basic
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:ref:`Cluster Data Model <cluster_data_model_definition>` for each
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:ref:`Goal <goal_definition>`, usable in the associated
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:ref:`Strategies <strategy_definition>` through some helper classes in order
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to:
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- simplify the development of a new
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:ref:`Strategy <strategy_definition>` for a given
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:ref:`Goal <goal_definition>` when there already are some existing
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:ref:`Strategies <strategy_definition>` associated to the same
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:ref:`Goal <goal_definition>`
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- avoid duplicating the same code in several
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:ref:`Strategies <strategy_definition>` associated to the same
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:ref:`Goal <goal_definition>`
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- have a better consistency between the different
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:ref:`Strategies <strategy_definition>` for a given
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:ref:`Goal <goal_definition>`
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- avoid any strong coupling with any external
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:ref:`Cluster Data Model <cluster_data_model_definition>`
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(the proposed data model acts as a pivot data model)
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There may be various
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:ref:`generic and basic Cluster Data Models <cluster_data_model_definition>`
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proposed in Watcher helpers, each of them being adapted to achieving a given
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:ref:`Goal <goal_definition>`:
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- For example, for a
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:ref:`Goal <goal_definition>` which aims at optimizing the network
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:ref:`resources <managed_resource_definition>` the
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:ref:`Strategy <strategy_definition>` may need to know which
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:ref:`resources <managed_resource_definition>` are communicating together.
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- Whereas for a :ref:`Goal <goal_definition>` which aims at optimizing thermal
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and power conditions, the :ref:`Strategy <strategy_definition>` may need to
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know the location of each compute node in the racks and the location of each
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rack in the room.
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Note however that a developer can use his/her own
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:ref:`Cluster Data Model <cluster_data_model_definition>` if the proposed data
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model does not fit his/her needs as long as the
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:ref:`Strategy <strategy_definition>` is able to produce a
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:ref:`Solution <solution_definition>` for the requested
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:ref:`Goal <goal_definition>`.
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For example, a developer could rely on the Nova Data Model to optimize some
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compute resources.
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The :ref:`Cluster Data Model <cluster_data_model_definition>` may be persisted
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in any appropriate storage system (SQL database, NoSQL database, JSON file,
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XML File, In Memory Database, ...).
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"""
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import abc
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import six
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@six.add_metaclass(abc.ABCMeta)
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class BaseClusterModelCollector(object):
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@abc.abstractmethod
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def get_latest_cluster_data_model(self):
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raise NotImplementedError()
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