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