CREATE_FAILED Conflict: resources.ADC_scaling_group.resources[3].resources.sig_trunk: Port <uuid> is currently in use and is not eligible for use as a parent port

Issue

• Intermittent error while creating multiple instances connected to a trunk port using heat templates. The error can look like this:

2023-01-23 13:24:11Z [IMS_Partner_vSBG-2.ADC_scaling_group]: CREATE_IN_PROGRESS  state changed
2023-01-23 13:26:44Z [IMS_Partner_vSBG-2.ADC_scaling_group]: CREATE_FAILED  Conflict: resources.ADC_scaling_group.resources[3].resources.sig_trunk: Port 7deca921-7765-496a-87e2-2a2fb59fce7c is currently in use and is not eligible for use as a parent port.
Neutron server returns request_ids: ['req-cc29eaa0-c5ba-4e68-a286-1a6a4a8ae
2023-01-23 13:26:44Z [IMS_Partner_vSBG-2]: CREATE_FAILED  Resource CREATE failed: Conflict: resources.ADC_scaling_group.resources[3].resources.sig_trunk: Port 7deca921-7765-496a-87e2-2a2fb59fce7c is currently in use and is not eligible for use as a parent port.