Protection Segments

Overview

Protection segments are logical groupings of compute hosts that share a recovery policy. When a host in a segment fails, Instance HA evacuates all protected instances to other healthy hosts within the same segment. Segments define the fault domain boundary — instances can only be recovered to hosts within the same segment.

Prerequisites

An active Polystack account with administrator access
Instance HA service enabled on the platform
Compute hosts available to register in segments

View Segments

Dashboard
CLI

Navigate to Segments

Navigate to Instance HA > Segments in the sidebar.

Review the segment list

The segment list displays all protection groups on the platform.

Column	Description
Name	Segment identifier (clickable to view details)
UUID	Unique segment identifier
Recovery Method	How instances are relocated after a host failure
Service Type	The type of service protected (e.g., `compute`)
Description	Optional note about the segment’s purpose

Use the search/filter bar to narrow the list:

Filter	Type
Recovery Method	Text search
Service Type	Text search

Source credentials

source openrc.sh

openstack segment list

openstack segment show <segment-uuid>

openstack segment host list <segment-uuid>

Create a Segment

The Dashboard provides a two-step wizard for creating a segment and adding hosts in a single workflow.

Dashboard
CLI

Open the Create Segment wizard

Navigate to Instance HA > Segments and click Create Segment. The wizard opens with two steps.

Step 1 — Configure the segment

Fill in the segment details:

Field	Type	Required	Default	Description
Segment Name	Text input	Yes	—	Human-readable name for the segment
Recovery Method	Dropdown	Yes	`auto`	Algorithm for selecting evacuation targets
Service Type	Text input	Yes	`compute`	Service type (fixed, not editable)
Description	Text area	No	—	Optional notes about the segment

Recovery Method options:

Value	Description
`auto`	Evacuate to any healthy host in the segment
`auto_priority`	Evacuate using priority-based host selection
`reserved_host`	Evacuate only to pre-designated standby hosts
`rh_priority`	Prefer reserved hosts, fall back to any host

Click Next to proceed. The segment is created at this step.

Step 2 — Add hosts to the segment

A table of available compute hosts is displayed. Select one or more hosts to add to the segment.The host selection table shows:

Column	Description	Editable
Name	Compute host name	No
Zone	Availability zone of the host	No
Updated	Last update timestamp	No
Reserved	Designate as standby host for failover	Yes (toggle switch)
Type	Host type identifier	Yes (text input)
Control Attributes	Monitoring attributes (e.g., SSH, IPMI)	Yes (text input)
On Maintenance	Whether the host is in maintenance mode	Yes (toggle switch)

Only compute hosts that are not already assigned to another segment appear in the selection table. Each host can belong to only one segment.

Set Reserved to Yes for hosts that should remain idle as standby capacity. Reserved hosts are used by the reserved_host and rh_priority recovery methods.

Select your hosts and click Confirm to complete the wizard.

Create the segment

Create a failover segment

openstack segment create \
  --recovery-method auto \
  --service-type compute \
  --description "Production compute segment" \
  prod-segment

Add hosts to the segment

Add a compute host

openstack segment host create <segment-uuid> \
  --name <compute-hostname> \
  --type compute \
  --control-attributes "SSH" \
  --reserved false \
  --on-maintenance false

Repeat for each host in the segment.

View Segment Details

Dashboard
CLI

Click a segment name in the list to open the detail page. Two tabs are available:Detail tab — Segment configuration:

Field	Description
Recovery Method	Current recovery algorithm
Service Type	Protected service type
Enabled	Whether the segment is active (Yes/No)
Created At	Creation timestamp
Updated At	Last modification timestamp

Hosts tab — All hosts registered in this segment:

Column	Description
Name	Host name (clickable to view host details)
UUID	Unique host identifier
Reserved	Whether the host is a standby node (Yes/No)
Type	Host type identifier
Control Attribute	Monitoring attributes
On Maintenance	Whether the host is in maintenance mode (Yes/No)
Failover Segment	Link back to the parent segment

openstack segment show <segment-uuid>

openstack segment host list <segment-uuid>

openstack segment host show <segment-uuid> <host-uuid>

Edit a Segment

Dashboard
CLI

Open the edit dialog

Navigate to Instance HA > Segments. Click the Update action (the first action button) on the segment row.

Update segment fields

You can update:

Field	Editable
Segment Name	Yes
Recovery Method	Yes (same 4 options as create)
Description	Yes

Save changes

Click Confirm to save the updated segment.

Update segment recovery method

openstack segment update <segment-uuid> \
  --recovery-method reserved_host

Add a Host to an Existing Segment

Dashboard
CLI

Open the Add Host dialog

Navigate to Instance HA > Segments. Click the More dropdown on a segment row and select Add Host.

Configure the host

Field	Type	Required	Default	Description
Segment Name	Text (disabled)	—	Current segment	Read-only reference
Host Name	Dropdown	Yes	—	Select from available compute hosts
Reserved	Toggle switch	No	Off	Standby host designation
Type	Text input	Yes	—	Host type identifier
Control Attributes	Text input	Yes	—	Monitoring attributes
On Maintenance	Toggle switch	No	Off	Maintenance mode flag

Only compute hosts not already assigned to any segment appear in the Host Name dropdown.

Add the host

Click Confirm. The host appears in the segment’s Hosts tab.

Add host to segment

openstack segment host create <segment-uuid> \
  --name <compute-hostname> \
  --type compute \
  --control-attributes "SSH" \
  --reserved false \
  --on-maintenance false

Delete a Segment

Dashboard
CLI

Navigate to Instance HA > Segments. Click the More dropdown on a segment row and select Delete, or select multiple segments using checkboxes and click Delete in the batch actions bar.Confirm the deletion in the dialog.

Deleting a segment removes all host registrations within it. Instances on those hosts will no longer be automatically recovered on host failure.

Delete a segment

openstack segment delete <segment-uuid>

Recovery Method Reference

Method	Evacuation Target	Capacity Guarantee	Use Case
`auto`	Any available host in the segment	None — depends on current load	General-purpose workloads
`auto_priority`	Priority-based host selection	None — best-effort prioritization	Workloads with preferred targets
`reserved_host`	Reserved standby hosts only	Guaranteed — reserved hosts are idle	SLA-critical workloads
`rh_priority`	Reserved hosts first; any host if full	Best-effort with preference	Mixed critical and general workloads

For most deployments, auto is the recommended starting point. Use reserved_host or rh_priority only when you have dedicated standby capacity and strict recovery time requirements.

Next Steps

Recovery Workflows

Understand how the recovery engine executes failover and tracks progress

Monitoring Status

Track live and historical recovery events in the Dashboard

How It Works

Understand the end-to-end detection and recovery architecture

Instance HA Admin Guide

Configure recovery policies, monitors, and engine settings

Core Services

Other Services

Overview

View Segments

Navigate to Segments

Review the segment list

Create a Segment

Open the Create Segment wizard

Step 1 — Configure the segment

Step 2 — Add hosts to the segment

Create the segment

Add hosts to the segment

View Segment Details

Edit a Segment

Open the edit dialog

Update segment fields

Save changes

Add a Host to an Existing Segment

Open the Add Host dialog

Configure the host

Add the host

Delete a Segment

Recovery Method Reference

Next Steps

Recovery Workflows

Monitoring Status

How It Works

Instance HA Admin Guide

​Overview

​View Segments

Navigate to Segments

Review the segment list

​Create a Segment

Open the Create Segment wizard

Step 1 — Configure the segment

Step 2 — Add hosts to the segment

Create the segment

Add hosts to the segment

​View Segment Details

​Edit a Segment

Open the edit dialog

Update segment fields

Save changes

​Add a Host to an Existing Segment

Open the Add Host dialog

Configure the host

Add the host

​Delete a Segment

​Recovery Method Reference

​Next Steps

Recovery Workflows

Monitoring Status

How It Works

Instance HA Admin Guide

Overview

View Segments

Create a Segment

View Segment Details

Edit a Segment

Add a Host to an Existing Segment

Delete a Segment

Recovery Method Reference

Next Steps