Spec for Grafana proxy datasource
Spec for a new datasource to collect metrics using Grafana as a proxy to the databases it integrates with. Change-Id: Id224bf37a72347e634567c933c42a12ef9b048d3 Implements: blueprint grafana-proxy-datasource
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This work is licensed under a Creative Commons Attribution 3.0 Unported
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License.
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http://creativecommons.org/licenses/by/3.0/legalcode
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========================
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Grafana proxy datasource
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========================
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https://blueprints.launchpad.net/watcher/+spec/grafana-proxy-datasaource
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Watcher requires metrics from compute nodes and instances to perform the
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resource optimization. Metrics are retrieved using several different
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datasources such as Gnocchi and Monasca, however, not every OpenStack cloud
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might have the available datasources deployed. Grafana can be implemented as an
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additional datasource that can be used to retrieve metrics from
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`several different databases`_ that the Grafana endpoint is configured to use.
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.. _several different databases: https://grafana.com/plugins?type=datasource`
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Problem description
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===================
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Not every OpenStack cloud might use the currently available datasources
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limiting the use of Watcher. By offering a widely used monitoring platform as
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datasource with flexible configurations options more OpenStack clouds could
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start using Watcher.
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Use Cases
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----------
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As a service operator I want Watcher to integrate with currently deployed
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monitoring solutions.
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As a service operator I want to limit the amount of external credentials I have
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to configure for Watcher.
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Proposed change
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===============
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The new Grafana datasource will be able to query for different metrics
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depending on what is configured by the end user. Flexible configuration options
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will allow Grafana to work for each user's configuration. Some of these options
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will be configurable per metric using key value pairs in a dictionary. These
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options are called maps as they map the value to a specific metric.
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Configuration options include:
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* Endpoint url
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* Authorization token
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* Project id map
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* Attribute map
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* Database map
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* Translator map
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* Query map
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A configuration example configured for the ``host_cpu_usage`` and
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``instance_cpu_usage`` metrics could look as follows:
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::
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[grafana_client]
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token = uyyNKUJOZiLW7AVKRF7XAAAAQQDzoXbnS6cOxxcqJfS8ZEQyxgakF0bSUo0D==
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base_url = https://grafana.ch/api/datasources/proxy/
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project_id_map = host_cpu_usage:1337,instance_cpu_usage:4337
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metric_db_map = host_cpu_usage:production_db,instance_cpu_usage:production_db
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attribute_map = host_cpu_usage:hostname,instance_cpu_usage:human_id
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translator_map = host_cpu_usage:influxdb,instance_cpu_usage:influxdb
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query_map = host_cpu_usage:SELECT 100-{0}("{0}_value") FROM {3}.cpu_percent
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WHERE ("host" =~ /^{1}$/ AND "type_instance" =~/^idle$/ AND
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time > now()-{2}m),instance_cpu_usage:SELECT 100-{0}("{0}_value")
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FROM {3}.cpu_percent WHERE ("host" =~ /^{1}$/ AND "type_instance"
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=~/^idle$/ AND time > now()-{2}m)
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Grafana uses project ids to proxy to different ``databases`` each of these
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projects could contain a different type of ``database``. **The term project**
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**will be used throughout this document to prevent possible confusion**.
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All the desired metrics can be collected from multiple project or a single one
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depending on how the monitoring is configured but is limited to a single metric
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per project. This is because there is no method to aggregate a single metric
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across multiple projects.
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The way queries have to be sent to the endpoint and how to interpret the
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retrieved data will depend upon the project behind Grafana. To account for
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these differences between projects specific translators will be developed.
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The influxdb translator will be developed first. The translator map is used
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to perform the correct translations per metric depending on the type of
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project.
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Projects could contain one or more databases similar to schema's in MySQL. The
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database map allows to define a specific database per metric.
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Similar to the project map and the database map is the query map. This map
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contains the queries that will be send to the project to retrieve metrics.
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Queries are depended on the type of project and in the case of influxdb they
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are similar to SQL statements.
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The attribute map is used to select specific attribute from the resource
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objects. This is necessary because the attribute used as identifier in projects
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can differ per deployment and per metric.
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From the query map the entries will be formatted so that essential information
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for retrieving the specific metric for the desired host can be achieved.
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::
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query = 'SELECT "{0}_value" FROM cpu_util WHERE host =~ /^{1}$/ AND time > '
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'now() - {2}m'
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query.format(aggregate, attribute, period, translator_specific)
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The format options can be extended overtime in case other specific
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projects such as elastic search require different parameters to successfully
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build a query.
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The initial format options will be:
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* {0} = aggregate
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* {1} = attribute
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* {2} = period
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* {3} = { influxdb: retention_period, }
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Because the amount of metrics available to Grafana depends on user
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configuration some minor changes are made to the datasource manager to build
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the metric list for Grafana at runtime.
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Instead of configuration many parameters using the default configuration file
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`the metric yaml`_ can used to set the configuration but the expected
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parameters differ from other datasources because of the large amount of
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parameters.
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::
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grafana:
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host_cpu_usage:
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project: 1337
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db: production_db
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attribute: hostname
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translator: influxdb
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query: SELECT 100-{0}("{0}_value") FROM {3}.cpu_percent
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WHERE ("host" =~ /^{1}$/ AND "type_instance" =~/^idle$/ AND
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time > now()-{2}m)
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.. _the metric yaml: https://specs.openstack.org/openstack/watcher-specs/specs/train/approved/file-based-metricmap.html
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Alternatives
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------------
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Datasources for individual projects that Grafana integrates with could be
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developed but this would be significantly more development effort and possibly
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complicate authorization as it would have to be configured per database.
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Data model impact
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-----------------
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None
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REST API impact
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---------------
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None
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Security impact
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---------------
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The configuration file will need to contain the Grafana authorization token
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which provides read access to the databases Grafana is configured for.
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The configuration file already contains other important credentials.
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Notifications impact
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--------------------
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None
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Other end user impact
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---------------------
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None
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Performance Impact
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------------------
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None
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Other deployer impact
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---------------------
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None
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Developer impact
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----------------
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None
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Implementation
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==============
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Assignee(s)
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-----------
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Primary assignee:
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Dantali0n
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Work Items
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----------
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* Configuration options
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* General Grafana datasource
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* Translator interface
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* InfluxDB translator
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* Unit tests for Grafana
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* Unit tests for translators
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Dependencies
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============
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* The communication with Grafana is realized using the requests library
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Testing
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=======
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Unit tests for both the datasource itself as well as the translator base class
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and any subsequent translators will be created.
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Documentation Impact
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====================
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A page containing documentation on how end user's can configure the options
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to successfully use Grafana as a datasource will be created.
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References
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==========
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* https://specs.openstack.org/openstack/watcher-specs/specs/train/approved/formal-datasource-interface.html
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* https://specs.openstack.org/openstack/watcher-specs/specs/train/approved/file-based-metricmap.html
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History
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=======
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.. list-table:: Revisions
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:header-rows: 1
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* - Release Name
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- Description
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* - Train
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- Introduced
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