56d0a0d6ea
The original documentation update review [1] had some additional comments for improvements. The commit adds the suggested changes. [1] https://review.opendev.org/c/openstack/watcher/+/951025 Change-Id: I4b4624e2dbc4c6a5f888ec77d6a03b8f66ff0a23
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5.4 KiB
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148 lines
5.4 KiB
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===================================
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Workload Balance Migration Strategy
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===================================
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Synopsis
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--------
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**display name**: ``Workload Balance Migration Strategy``
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**goal**: ``workload_balancing``
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.. watcher-term:: watcher.decision_engine.strategy.strategies.workload_balance.WorkloadBalance
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Metrics
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*******
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The ``workload_balance`` strategy requires the following metrics:
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======================= ============ ======= =========== ======================
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metric service name plugins unit comment
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======================= ============ ======= =========== ======================
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``cpu`` ceilometer_ none percentage CPU of the instance.
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Used to calculate the
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threshold
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``memory.resident`` ceilometer_ none MB RAM of the instance.
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Used to calculate the
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threshold
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======================= ============ ======= =========== ======================
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.. _ceilometer: https://docs.openstack.org/ceilometer/latest/admin/telemetry-measurements.html#openstack-compute
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.. note::
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* The parameters above reference the instance CPU or RAM usage, but
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the threshold calculation is based of the CPU/RAM usage on the
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hypervisor.
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* The RAM usage can be calculated based on the RAM consumed by the instance,
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and the available RAM on the hypervisor.
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* The CPU percentage calculation relies on the CPU load, but also on the
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number of CPUs on the hypervisor.
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* The host memory metric is calculated by summing the RAM usage of each
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instance on the host. This measure is close to the real usage, but is
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not the exact usage on the host.
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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.weight.WeightPlanner
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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`` String instance_cpu_usage Workload balance base on cpu or
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ram utilization. Choices:
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['instance_cpu_usage',
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'instance_ram_usage']
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``threshold`` Number 25.0 Workload threshold for migration.
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Used for both the source and the
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destination calculations.
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Threshold is always a percentage.
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``period`` Number 300 Aggregate time period of
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ceilometer
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``granularity`` Number 300 The time between two measures in
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an aggregated timeseries of a
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metric.
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This parameter is only used
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with the Gnocchi data source,
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and it must match to any of the
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valid archive policies for the
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metric.
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================ ====== ==================== ==================================
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Efficacy Indicator
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------------------
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None
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Algorithm
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---------
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For more information on the Workload Balance Migration Strategy please refer
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to: https://specs.openstack.org/openstack/watcher-specs/specs/mitaka/implemented/workload-balance-migration-strategy.html
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How to use it ?
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---------------
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Create an audit template using the Workload Balancing strategy.
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.. code-block:: shell
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$ openstack optimize audittemplate create \
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at1 workload_balancing --strategy workload_balance
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Run an audit using the Workload Balance strategy. The result of
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the audit should be an action plan to move VMs from any host
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where the CPU usage is over the threshold of 26%, to a host
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where the utilization of CPU is under the threshold.
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The measurements of CPU utilization are taken from the configured
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datasouce plugin with an aggregate period of 310.
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.. code-block:: shell
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$ openstack optimize audit create -a at1 -p threshold=26.0 \
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-p period=310 -p metrics=instance_cpu_usage
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Run an audit using the Workload Balance strategy to
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obtain a plan to balance VMs over hosts with a threshold of 20%.
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In this case, the stipulation of the CPU utilization metric
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measurement is a combination of period and granularity.
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.. code-block:: shell
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$ openstack optimize audit create -a at1 \
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-p granularity=30 -p threshold=20 -p period=300 \
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-p metrics=instance_cpu_usage --auto-trigger
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External Links
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--------------
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None.
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