> 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/generic/the-openstack-hypervisor-list-fails-with-500-internal-server-error-when-using-compute-api-microversi.md).

# Hypervisor List Fails With "500 Internal Server" Error When Using Compute API Microversion

## Problem

The `openstack hypervisor list` command fails with a 500 Internal Server Error, even though `nova hypervisor-list` and `openstack hypervisor show <ID>` work as expected.

The failure occurs specifically when querying the `/os-hypervisors/detail` API endpoint, which is used by the OpenStack unified client. For Self-Hosted PCD users, the `nova-api-osapi`pod logs shows repeated warnings about invalid UUIDs, such as:

```bash
Invalid uuid: nova. To ensure interoperability, identifiers should be a valid uuid.
```

## Environment

* Private Cloud Director Virtualization - v2025.4 and Higher
* Self-Hosted Private Cloud Director Virtualization - v2025.4 and Higher
* Component: OpenStack-CLI version 8.1.0 and above.

## Cause

This is an expected behavior, starting from **Compute API micro version 2.53**, Nova replaced integer-based service and hypervisor IDs with **UUIDs** to ensure global uniqueness across multi-cell deployments.

In upgraded environments (from pre-Newton/Ocata releases), the `compute_nodes` or `services` tables may still contain old non-UUID identifiers (e.g., `nova`, `compute-01`, or blank fields).

When `/os-hypervisors/detail` is queried using microversion ≥ 2.53, Nova attempts to serialize these IDs as UUIDs. If invalid values are encountered, an internal Python `OSError` or `ValueError` is raised, leading to the 500 error.

Older microversions (≤ 2.52) continue to work as they still rely on integer-based IDs and do not enforce UUID validation.

## Diagnostics

* Command failure observed:

```bash
$ openstack hypervisor list

HttpException: 500: Server Error for url: https://[PCD_FQDN]/nova/v2.1/[ID]/os-hypervisors/detail, Unexpected API Error. Please report this at http://bugs.launchpad.net/nova/ and attach the Nova API log if possible.
<class 'oslo_messaging.exceptions.MessagingTimeout'>
```

* Verification using older micro version:

```bash
$ openstack --os-compute-api-version 2.1 hypervisor list

+-----+--------------------------+-----------------+---------------+-------+
|  ID | Hypervisor Hostname      | Hypervisor Type | Host IP       | State |
+-----+--------------------------+-----------------+---------------+-------+
| [ID]| [HOSTNAME]               | QEMU            | [IP]          | up    |
```

## Resolution

Run with a supported micro version ≤ **2.52** (before UUID enforcement):

```bash
$ openstack --os-compute-api-version 2.1 hypervisor list
```

## Validation

Command working after using older microversion:

```bash
$ openstack --os-compute-api-version 2.1 hypervisor list
```

The command should return a valid hypervisor list with no 500 errors, and For Self Hosted PCD users, `nova-api-osapi` pod logs should no longer display “`Invalid uuid`” warnings.

## Additional Information

**References:**

* [Nova Compute API Microversion History — 2.53: Change service and hypervisor IDs to UUIDs](https://docs.openstack.org/nova/latest/reference/api-microversion-history.html)
* [API Reference: GET /os-hypervisors/detail](https://docs.openstack.org/api-ref/compute/?expanded=list-hypervisors-detail)
* [Blueprint: Use UUIDs in services and os-hypervisors APIs](https://blueprints.launchpad.net/nova/+spec/service-hyper-uuid-in-api)
* [Nova Source Commit — UUID Enforcement in Hypervisors API](https://opendev.org/openstack/nova/src/commit/614403370a877d6c8ab841cd593f822d4675319b/nova/api/openstack/compute/hypervisors.py)


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