9761207d8a
This patch set adds how-to-use documentation for Watcher Overload standard deviation algorithm. Change-Id: I75d7cd0ff8507ca70efb6d9668ae9fbf651a7f97
132 lines
4.7 KiB
ReStructuredText
132 lines
4.7 KiB
ReStructuredText
=============================================
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Watcher Overload standard deviation algorithm
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=============================================
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Synopsis
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--------
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**display name**: ``workload_stabilization``
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**goal**: ``workload_balancing``
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.. watcher-term:: watcher.decision_engine.strategy.strategies.workload_stabilization
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Requirements
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------------
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Metrics
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*******
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The *workload_stabilization* strategy requires the following metrics:
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============================ ============ ======= =======
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metric service name plugins comment
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============================ ============ ======= =======
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``compute.node.cpu.percent`` ceilometer_ none
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``hardware.memory.used`` ceilometer_ SNMP_
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``cpu_util`` ceilometer_ none
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``memory.resident`` ceilometer_ none
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============================ ============ ======= =======
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.. _ceilometer: http://docs.openstack.org/admin-guide/telemetry-measurements.html#openstack-compute
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.. _SNMP: http://docs.openstack.org/admin-guide/telemetry-measurements.html
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Cluster data model
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******************
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Default Watcher's Compute cluster data model:
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.. watcher-term:: watcher.decision_engine.model.collector.nova.NovaClusterDataModelCollector
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Actions
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*******
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Default Watcher's actions:
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.. list-table::
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:widths: 30 30
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:header-rows: 1
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* - action
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- description
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* - ``migration``
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- .. watcher-term:: watcher.applier.actions.migration.Migrate
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Planner
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*******
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Default Watcher's planner:
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.. watcher-term:: watcher.decision_engine.planner.default.DefaultPlanner
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Configuration
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-------------
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Strategy parameters are:
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==================== ====== ===================== =============================
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parameter type default Value description
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==================== ====== ===================== =============================
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``metrics`` array |metrics| Metrics used as rates of
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cluster loads.
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``thresholds`` object |thresholds| Dict where key is a metric
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and value is a trigger value.
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``weights`` object |weights| These weights used to
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calculate common standard
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deviation. Name of weight
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contains meter name and
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_weight suffix.
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``instance_metrics`` object |instance_metrics| Mapping to get hardware
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statistics using instance
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metrics.
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``host_choice`` string retry Method of host's choice.
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There are cycle, retry and
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fullsearch methods. Cycle
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will iterate hosts in cycle.
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Retry will get some hosts
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random (count defined in
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retry_count option).
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Fullsearch will return each
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host from list.
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``retry_count`` number 1 Count of random returned
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hosts.
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==================== ====== ===================== =============================
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.. |metrics| replace:: ["cpu_util", "memory.resident"]
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.. |thresholds| replace:: {"cpu_util": 0.2, "memory.resident": 0.2}
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.. |weights| replace:: {"cpu_util_weight": 1.0, "memory.resident_weight": 1.0}
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.. |instance_metrics| replace:: {"cpu_util": "hardware.cpu.util", "memory.resident": "hardware.memory.used"}
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Efficacy Indicator
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------------------
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.. watcher-func::
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:format: literal_block
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watcher.decision_engine.goal.efficacy.specs.ServerConsolidation.get_global_efficacy_indicator
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Algorithm
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---------
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You can find description of overload algorithm and role of standard deviation
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here: https://specs.openstack.org/openstack/watcher-specs/specs/newton/implemented/sd-strategy.html
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How to use it ?
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---------------
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.. code-block:: shell
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$ openstack optimize audittemplate create \
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at1 workload_balancing --strategy workload_stabilization
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$ openstack optimize audit create -a at1 \
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-p thresholds='{"memory.resident": 0.05}' \
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-p metrics='["memory.resident"]'
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External Links
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--------------
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- `Watcher Overload standard deviation algorithm spec <https://specs.openstack.org/openstack/watcher-specs/specs/newton/implemented/sd-strategy.html>`_
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