Description of problem:

"preferred" key could be set for some location by specific driver (if this feature is implemented there). I can see related code in manila/share/drivers/tegile/tegile.py and in manila/share/drivers/netapp/dataontap/cluster_mode/lib_base.py.
I don't believe that there is a way to set it manually.

https://docs.openstack.org/manila/train/admin/export_location_metadata.html
preferred - May be True or False. Defaults to False. Indicates that clients should prefer to mount this export location over other export locations that are not preferred. This may be used by drivers which have fast/slow paths to indicate to clients which paths are faster. It could be used to indicate a path is preferred for another reason, as long as the reason isn’t one that changes over the life of the manila-share service. This key is always visible through the REST API.
Version-Release number of selected component (if applicable):

https://github.com/openstack/manila/blob/master/manila/share/drivers/container/driver.py#L690-L733

How reproducible:

Steps to Reproduce:
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Actual results:
can't set the preferred parameter manually for export_location on the Manila

Expected results:
there is a way to set the preferred parameter manually

Additional info:

Work started as part of 2023 Outreachy round here: https://review.opendev.org/q/topic:%22metadata-export-location%22