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Overview

The Resource Optimizer relies on Xloud Compute for both cluster state collection and migration execution. All optimization actions that produce live migrations require compute hosts to support live migration — which in turn requires shared storage for instance disks. This page covers the compute requirements, verification steps, and configuration adjustments needed before enabling optimization in production.
Prerequisites
  • Administrator privileges
  • Xloud Compute deployed and operational
  • Xloud Distributed Storage or equivalent shared storage for instance volumes

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Shared Storage Requirement

Live migration requires that instance disks are backed by shared storage (Xloud Distributed Storage or equivalent). Instances with local ephemeral disks cannot be live-migrated. Such instances will cause actions to fail during plan execution.
Verify that the instances targeted by optimization are using shared storage:
Check instance storage backend
openstack server show <instance-id> \
  -f value -c "os-extended-volumes:volumes_attached"
Instances with no attached volumes (or with ephemeral disk only) cannot be live-migrated. Work with project owners to migrate critical ephemeral-disk instances to volume-backed equivalents before enabling optimization strategies that include those instances.

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Verify Compute Host Availability

Optimization actions only target compute hosts that are up, enabled, and not in maintenance state.
Check all compute services
openstack compute service list --service nova-compute
ColumnRequired Value
Stateup
Statusenabled
Hosts with state: down or status: disabled are automatically excluded from optimization targets. Disabled hosts do not receive live-migrated instances.

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Verify Live Migration Capability

Check migration capability per host
openstack hypervisor show <hostname> \
  -f value -c hypervisor_hostname -c state -c status
Perform a test live migration between two hosts in the optimization segment:
Test live migration between hosts
openstack server migrate <test-instance-id> \
  --live-migration \
  --host <destination-host>

openstack server show <test-instance-id> \
  -f value -c status
Expected: instance returns to ACTIVE status on the destination host.

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CPU Compatibility for Live Migration

Live migration between hosts with different CPU architectures or feature sets can fail. Configure a common CPU baseline in the Compute service to ensure compatibility across all hosts in the optimization segment.

Open Advanced Configuration

Open XDeploy and navigate to Advanced Configuration. In the Service Tree (left panel), select nova.

Edit the Compute Configuration

Click New File or select an existing nova.conf from the File Browser (right panel). Add the following in the Code Editor (center panel):
/etc/xavs/config/nova/nova.conf
[libvirt]
cpu_mode = custom
cpu_model = Cascadelake-Server-noTSX

Save and Apply

Click Save Current File. Return to Operations and run reconfigure to apply the CPU compatibility settings across all compute hosts.
CPU compatibility baseline configured and applied via XDeploy.
Use cpu_mode = custom with a CPU model that represents the lowest common denominator across all compute hosts in the optimization segment. This is especially important in clusters with heterogeneous hardware generations.

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Host Aggregates for Optimization Scope

Use host aggregates to define which hosts are eligible for optimization. Assign all hosts intended for consolidation to a single aggregate, then scope your audits to that aggregate:
Create optimization aggregate
openstack aggregate create optimization-zone
openstack aggregate add host optimization-zone compute-01
openstack aggregate add host optimization-zone compute-02
openstack aggregate add host optimization-zone compute-03

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Validation

Navigate to Admin → Compute → Hypervisors. Verify:
  • All compute hosts show State: Up and Status: Enabled
  • No hosts are in maintenance or down state
All compute hosts are up and enabled, ready to serve as migration targets.

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Next Steps

Action Policies

Configure manual approval vs automatic execution for optimization plans.

Security

Secure the service account used by the Applier to call the Compute API.

Troubleshooting

Diagnose live migration failures during plan execution.

Compute Admin Guide

Configure compute hosts, shared storage, and live migration settings.