The API reference for listing servers says that the all_tenants
filter parameter is available for non-admins which is likely
a mistake because of it being in the _get_server_search_options
method, but all_tenants is admin-only by default policy because
of the os_compute_api:servers:index:get_all_tenants and
os_compute_api:servers:detail:get_all_tenants policy rules.
This change fixes the API reference to remove all_tenants from
the list of non-admin filter parameters and also adds a note to
the _get_server_search_options method to avoid future confusion.
Change-Id: I0e937afbdf8e19d2efd626047913d4c8a9b88b76
Closes-Bug: #1828042
Matt Riedemann
57646dfe77