> For the complete documentation index, see [llms.txt](https://platform9.com/kb/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://platform9.com/kb/pcd/gpu/gpu-vm-cold-migration-resize-fails-insufficient-compute-resources.md).
# GPU VM Cold Migration / Resize Fails: Insufficient Compute Resources
## Problem
A GPU Passthrough VM transitions to the ERROR state during cold migration or resize. The operation fails even when the destination host has sufficient physical GPU resources available.
## Environment
* Self-Hosted Private Cloud Director Virtualization — v2025.10-180 and above
* Private Cloud Director Virtualization — v2025.10-180 and above
* Components: GPU and Compute Service
## Diagnostics
* Check the PCI configuration, and verify the GPU passthrough device (`type-PF`).
[pci]
alias = {"vendor_id": "[VENDOR_ID]", "product_id": "[PRODUCT_ID]", "device_type": "type-PF","name": "[DEVICE_NAME]", "live_migratable": "yes"}
* Check `ostackhost.log` on the destination compute host for the following log entries:
INFO nova.compute.claims [instance: [INSTANCE_UUID]] Failed to claim: Claim pci failed
ERROR nova.compute.manager [instance: [INSTANCE_UUID]] Setting instance vm_state to ERROR: nova.exception.ComputeResourcesUnavailable: Insufficient compute resources: Claim pci failed.
* [Enable debug logging](https://platform9.com/kb/pcd/compute/how-to-enable-debug-logging#compute) and re-check `ostackhost.log`. With debug logging enabled, look for:
DEBUG nova.pci.stats PCI claim: Starting with 1 devices, request count: 1
DEBUG nova.pci.stats PCI claim: Request spec: [{'vendor_id': '[VENDOR_ID]', 'product_id': '[PRODUCT_ID]','dev_type': 'type-PF', 'live_migratable': 'true'}]
DEBUG nova.pci.utils PCI attribute check: key=live_migratable, spec_value=true, device_value=None
DEBUG nova.pci.utils PCI attribute mismatch: live_migratable spec="true" != device="None"
DEBUG nova.pci.stats Dropped 1 device(s) due to mismatched PCI attribute(s)
DEBUG nova.pci.stats Not enough PCI devices left to satisfy request after spec filtering
DEBUG nova.pci.stats PCI claim: Available: 0, Required: 1
**Key Indicator:** The `live_migratable` attribute is present in the PCI request spec (`true`) but is absent (`None`) from the available device pool — causing Nova to drop all matching devices and fail the claim.
## Cause
This is a regression introduced in **v2025.10-180**, where the `live_migratable=yes` flag was introduced to the PCI alias configuration (`nova.conf`) for GPU passthrough devices (`type-PF`). This flag is only valid for `type-VF` (vGPU / SR-IOV Virtual Function) devices that support live migration via kernel variant drivers.
For `type-PF` (PCI Passthrough / Physical Function) devices, live migration is NOT supported. When `live_migratable=yes` is set in the alias, Nova's PCI filter includes this attribute in the request spec. Since the physical device pool does not carry the `live_migratable` attribute, the comparison fails, and all available GPU devices are dropped — resulting in `Available: 0`.
**Affected Configuration**
The problematic configuration is present in `/opt/pf9/etc/nova/nova.conf` on GPU compute hosts in **v2025.10-180**:
{% code title="/opt/pf9/etc/nova/nova.conf " %}
```ini
[pci]
alias = {"vendor_id": "[VENDOR_ID]", "product_id": "[PRODUCT_ID]", "device_type": "type-PF","name": "[DEVICE_NAME]", "live_migratable": "yes"} ← INCORRECT
```
{% endcode %}
**Attribute Mismatch Flow**
During the issue, the below configuration is fed.
```ruby
{'vendor_id': '[VENDOR_ID]', 'product_id': '[PRODUCT_ID]', 'dev_type': 'type-PF', 'live_migratable': 'true'}
```
However, the below configurations are only supported in the device pool configurations:
```ruby
{'vendor_id': '[VENDOR_ID]', 'product_id': '[PRODUCT_ID]', 'dev_type': 'type-PF'}
# 'live_migratable' key is ABSENT
```
As a result:
```ruby
PCI attribute mismatch: live_migratable spec="true" != device="None" → Device dropped → Claim pci failed
```
## Resolution
* Live migration for GPU passthrough (`type-PF`) is not supported yet; `live_migratable` is reserved for the future `type-VF` (vGPU) support and is tracked in **PCD-6249**.
## Workaround
{% stepper %}
{% step %}
Remove `device_spec` from `nova.conf` under \[pci] section
Only remove the `device_spec` line — do not delete the entire `[pci]` section.
{% code title="GPU Host" %}
```bash
# Backup first
cp /opt/pf9/etc/nova/nova.conf /opt/pf9/etc/nova/nova.conf.bak
# Edit nova.conf and remove only the device_spec line under [pci]:
# device_spec = {"vendor_id": "", "product_id": ""}
vi /opt/pf9/etc/nova/nova.conf
```
{% endcode %}
{% endstep %}
{% step %}
Add the corrected PCI config to `nova-override.conf` (without live\_migratable)
{% code title="GPU Host" %}
```bash
# Backup first
cp /opt/pf9/etc/nova/nova-override.conf /opt/pf9/etc/nova/nova-override.conf.bak
# Append correct [pci] section
cat >> /opt/pf9/etc/nova/nova-override.conf << 'EOF'
[pci]
device_spec = {"vendor_id": "", "product_id": ""}
alias = {"vendor_id": "", "product_id": "", "device_type": "type-PF", "name": ""}
report_in_placement = True
EOF
```
{% endcode %}
{% hint style="info" %}
Do NOT include `live_migratable` in the alias.
{% endhint %}
{% endstep %}
{% step %}
Remove any existing `pci.conf` from `conf.d` - if present.
{% code title="GPU Host" %}
```bash
if [ -f /opt/pf9/etc/nova/conf.d/pci.conf ]; then
mv /opt/pf9/etc/nova/conf.d/pci.conf \
/opt/pf9/etc/nova/conf.d/pci.conf.bak
fi
```
{% endcode %}
{% endstep %}
{% step %}
Restart the Compute Service
{% code title="GPU Host" %}
```bash
sudo systemctl restart pf9-ostackhost
sudo systemctl status pf9-ostackhost
```
{% endcode %}
{% endstep %}
{% step %}
Verify the Hostagent convergence state.
{% code title="GPU Host" %}
```bash
systemctl status pf9-hostagent
tail -100 /var/log/pf9/hostagent.log | grep -i "converge\|error\|fail"
```
{% endcode %}
{% endstep %}
{% step %}
Validate cold migration and resize
After the service restarts successfully, test the following:
* Cold migration of a GPU VM between hosts
* GPU flavor resize (e.g., 8 GPU → 4 GPU)
{% endstep %}
{% endstepper %}
## Validation
To confirm the fix is applied, [Enable debug logging](https://platform9.com/kb/pcd/compute/how-to-enable-debug-logging#compute) and re-check `ostackhost.log` to verify the PCI claim no longer includes `live_migratable` in the request spec. A successful claim should show
{% code title="/var/log/pf9/ostackhost.log" %}
```ruby
DEBUG nova.pci.stats PCI claim: Request spec: [{'vendor_id': '[VENDOR_ID]', 'product_id': '[PRODUCT_ID]','dev_type': 'type-PF'}]
# No 'live_migratable' key present
DEBUG nova.pci.stats PCI claim: Available: 1, Required: 1
```
{% endcode %}
Compare with the failure pattern in the [#diagnostics](#diagnostics "mention")section.
## Additional Information
* This issue affects all GPU PCI passthrough configurations using `type-PF` in v2025.10-180 — not just NVIDIA H200.
***
---
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