> 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/pmo/solution/host-being-scheduled-erroneously.md).

# Host Being Scheduled Erroneously

## Problem

Instances are unexpectedly being scheduled to hosts which reside outside of the matching host aggregate as per the metadata of the flavor with which the instance was created.

## Environment

* Platform9 Managed OpenStack - v3.6.0-3.11.0
* Nova

## Cause

When adding or removing multiple hosts to an aggregate simultaneously, there was a race condition when reporting host aggregate data to *nova-scheduler* since an incremental update was being sent instead of querying the latest state in the Nova database.

## Resolution

The issue was addressed by modifying the behavior of the scheduler code to refresh the host aggregate data directly from the database. A fix for this bug (IAAS-9869) is included in Platform9 v3.11.1.


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