Hi Nova Team, We are currently facing an issue in Tacker (master branch) caused by a bug in Nova microversion 2.100, where scheduler_hints.group is returned as a list instead of a string in the server GET API response. Problem Statement: The server GET API (microversion 2.100) returns scheduler_hints.group as a list, whereas the API schema requires it to be a string UUID. This type mismatch causes server rebuild operations to fail with a 400 Bad Request error. Root Cause: Nova stores scheduler hints internally using DictOfListOfStringsField, so all values are kept as lists. When microversion 2.100 exposes scheduler hints in the API response, the group field is returned in its raw internal form without being converted back to the string format required by the API spec. Impact: This bug is causing test case failures in Tacker CI jobs, making our pipeline unstable. Detailed information about the bug can be found in the reports linked below: Nova Bug: https://bugs.launchpad.net/nova/+bug/2139275 We'd appreciate your help in reviewing and fixing this bug at the earliest, as it is actively impacting Tacker CI stability. Please let us know if you need any additional details from our side. Thanks in advance for your support! Thanks & Regards, Shivam Shukla (シヴァム・シュクラ) Mobile: +91-9450053922 E-mail: shivam.shukla3@india.nec.com The contents of this e-mail and any attachment(s) are confidential and intended for the named recipient(s) only. It shall not attach any liability on the originator or NEC Corporation India Private Limited or its affiliates. Any views or opinions presented in this email are solely those of the author and may not necessarily reflect the opinions of NEC Corporation India Private Limited or its affiliates. Any form of reproduction, dissemination, copying, disclosure, modification, distribution and / or publication of this message without the prior written consent of the author of this e-mail is strictly prohibited. If you have received this email in error please delete it and notify the sender immediately.