Strategy Configuration

Overview

Strategies are the algorithm plugins used by the Decision Engine to analyze the cluster and generate migration recommendations. Each strategy is tied to one or more optimization goals and accepts tuning parameters that control sensitivity thresholds, look-back periods, and metric selection. This page documents all available strategies and their configuration parameters.

Available Strategies

Strategy	Goal	Algorithm	Data Source Required
`server_consolidation`	Server Consolidation	Bin-packing — fill hosts before activating new ones	Compute API
`outlet_temperature`	Thermal Optimization	Heatmap — migrate from hot racks based on inlet temperature	Prometheus (temperature)
`workload_stabilization`	Workload Stabilization	Statistical variance analysis per instance	Telemetry time-series
`saving_energy`	Energy Savings	Consolidate + flag empty hosts for power-off	Compute API
`zone_migration`	Zone Rebalancing	Even distribution across availability zones	Compute API
`noisy_neighbor`	Noisy Neighbor	CPU steal contention detection between co-located instances	Telemetry
`basic_consolidation`	Consolidation (basic)	Threshold-based: migrate from hosts below utilization threshold	Compute API only

Configure Strategy Parameters

Per-Audit Parameters

Override defaults at audit creation time without changing the service configuration:

Create audit with custom parameters

openstack watcher audit create \
  --goal server_consolidation \
  --parameter threshold=0.15 \
  --parameter period=7200 \
  --name custom-threshold-audit

Service-Wide Defaults

Set platform defaults that apply to all audits which do not override specific parameters.

Web Console
CLI

Enable Dynamic Cluster Optimization

Open the deployment console and navigate to Configuration. Select the Advance Features tab and toggle Enable Dynamic Cluster Optimization to Yes. Click Save Configuration.

Configure Strategy Defaults

Navigate to Advanced Configuration. In the Service Tree (left panel), select watcher. Click New File or select an existing watcher.conf from the File Browser (right panel).Add the following in the Code Editor (center panel):

/etc/ironcore/config/watcher/watcher.conf

[watcher_strategies.server_consolidation]
threshold = 0.2
period = 3600

[watcher_strategies.workload_stabilization]
metric = cpu_util
granularity = 300
period = 7200

[watcher_strategies.outlet_temperature]
threshold = 35.0
period = 3600

Save and Apply

Click Save Current File. Return to Operations and run reconfigure to apply the strategy defaults to the Decision Engine.

Strategy defaults configured and applied via the deployment console.

Edit the configuration file directly:

/etc/ironcore/watcher/watcher.conf

[watcher_strategies.server_consolidation]
threshold = 0.2
period = 3600

[watcher_strategies.workload_stabilization]
metric = cpu_util
granularity = 300
period = 7200

[watcher_strategies.outlet_temperature]
threshold = 35.0
period = 3600

Restart the Decision Engine after configuration changes:

Restart Decision Engine

docker restart watcher_decision_engine

Parameter Reference

Parameter	Strategy	Default	Description
`threshold`	`server_consolidation`, `basic_consolidation`	`0.2`	Fraction below which a host is underutilized
`period`	All	`3600`	Look-back window in seconds for metric aggregation
`granularity`	Telemetry-backed	`300`	Metric sample granularity in seconds
`metric`	`workload_stabilization`	`cpu_util`	Metric used for stability scoring
`threshold`	`outlet_temperature`	`35.0`	Inlet temperature (°C) above which to evacuate racks

Verify Strategy Loading

Verify strategy plugins are loaded

docker exec watcher_decision_engine python3 -c "
from stevedore import driver
drv = driver.DriverManager(
    namespace='watcher_strategies',
    name='server_consolidation',
    invoke_on_load=False
)
print('Strategy loaded:', drv.driver)
"

List all registered strategies

openstack watcher strategy list

Polystack Production Enhancements

Server Group Awareness

All 14 strategies automatically respect server group affinity and anti-affinity constraints during automated migrations. Hard policies (affinity, anti-affinity) block invalid migrations. Soft policies adjust destination scoring weights. See Server Groups for configuration.

DRS Safety Checks

The workload balancing strategy includes production safety guardrails:

Check	Description
Max iterations	Configurable limit on migrations per audit cycle
Capacity validation	Pre-migration check ensures destination has sufficient resources
Concurrent migration limit	Prevents overloading the cluster with simultaneous migrations
Server group weight	Destination scoring adjusts based on soft-affinity/anti-affinity group membership

Automated Storage Tiering

The storage tier balance strategy automatically moves volumes between NVMe, SSD, and HDD pools based on IOPS activity and volume age. Configurable promotion and demotion thresholds. See Storage Tiers.

Next Steps

Data Sources

Connect the data sources required by each strategy.

Custom Strategies

Implement and deploy custom optimization strategy plugins.

Scheduling

Schedule recurring audits using the configured strategies.

Architecture

Review how strategies fit into the Decision Engine pipeline.

Core Services

Other Services

Overview

Available Strategies

Configure Strategy Parameters

Per-Audit Parameters

Service-Wide Defaults

Enable Dynamic Cluster Optimization

Configure Strategy Defaults

Save and Apply

Parameter Reference

Verify Strategy Loading

Polystack Production Enhancements

Server Group Awareness

DRS Safety Checks

Automated Storage Tiering

Next Steps

Data Sources

Custom Strategies

Scheduling

Architecture

​Overview

​Available Strategies

​Configure Strategy Parameters

​Per-Audit Parameters

​Service-Wide Defaults

Enable Dynamic Cluster Optimization

Configure Strategy Defaults

Save and Apply

​Parameter Reference

​Verify Strategy Loading

​Polystack Production Enhancements

​Server Group Awareness

​DRS Safety Checks

​Automated Storage Tiering

​Next Steps

Data Sources

Custom Strategies

Scheduling

Architecture

Overview

Available Strategies

Configure Strategy Parameters

Per-Audit Parameters

Service-Wide Defaults

Parameter Reference

Verify Strategy Loading

Polystack Production Enhancements

Server Group Awareness

DRS Safety Checks

Automated Storage Tiering

Next Steps