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Overview

Resizing an instance changes its — adjusting the vCPU, RAM, and disk allocation profile. The resize operation stops the instance, moves it to a host that satisfies the new flavor requirements if necessary, and restarts it. After the resize completes, a confirmation window allows you to accept or revert to the original flavor.
Resizing always requires a reboot. Schedule resize operations during a maintenance window for production workloads. For zero-downtime vertical scaling on supported instances, use Live vCPU/RAM Scaling — available through the Xloud Dashboard Actions menu with no reboot required.
Prerequisites
  • An instance in ACTIVE or SHUTOFF status
  • A target flavor with a root disk size ≥ the current root disk (downsizing disk is not permitted)
  • member or admin role in the project
  • CLI users: Xloud CLI configured and credentials sourced

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Resize Workflow

The resize process follows three phases:
PhaseInstance StatusAction Required
Resize initiatedRESIZEAutomatic — no action required
Awaiting confirmationVERIFY_RESIZEConfirm or revert within the window
ConfirmedACTIVEInstance running on new flavor
The confirmation window defaults to 24 hours. If you neither confirm nor revert within this period, the resize is automatically confirmed. Contact your administrator to adjust the confirmation window duration.

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Resize an Instance

Open the resize dialog

Navigate to Project → Compute → Instances. In the instance row, open the Actions dropdown and select Resize Instance.

Select a new flavor

In the Resize Instance dialog, select the target flavor from the list.
Flavors with a root disk smaller than the current instance’s root disk are unavailable (greyed out). You cannot reduce root disk size during a resize.
ColumnDescription
VCPUsNew virtual CPU allocation
RAMNew memory allocation
Root DiskRoot disk size (must be ≥ current)
Ephemeral DiskTemporary scratch disk
Click Resize to initiate the operation.

Wait for VERIFY_RESIZE status

The instance transitions through RESIZE → VERIFY_RESIZE. This typically completes within 1–5 minutes depending on whether a live migration is required.

Confirm or revert the resize

Once the instance reaches Verify Resize status:
  • Click Confirm Resize in the Actions dropdown to finalize the new flavor.
  • Click Revert Resize to return to the original flavor.
After confirming, instance status returns to Active with the new flavor applied. Verify the new flavor in the instance detail page.

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Downsize Considerations

Downsizing an instance (reducing vCPU or RAM) is supported provided the root disk size constraint is met. Consider the following before reducing resources:
ConsiderationDetail
Root diskTarget flavor root disk must be ≥ current root disk size
Running processesApplications may crash or degrade if memory falls below their working set
OS limitsSome OS configurations reserve a minimum amount of RAM — verify before downsizing
Application testingTest workload behavior on the target flavor in a non-production environment first
Downsizing a database server or memory-intensive application without testing in advance may cause service degradation or OOM failures after the resize is confirmed.

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Next Steps

Live vCPU/RAM Scaling

Scale vCPU and RAM on a running instance with no reboot or downtime

Reboot an Instance

Perform a soft or hard reboot without changing the instance flavor

Launch an Instance

Select the right flavor from the start to minimize future resize operations

Rescue an Instance

Recover from boot failures or lost access after a resize