---
upgrade:
  - |
    The filter and sort query parameters for server list API are
    now limited according to whitelists. The whitelists are different
    for admin and non-admin users.

    **Filtering**

    The whitelist for REST API filters for admin users:

    - access_ip_v4
    - access_ip_v6
    - all_tenants
    - auto_disk_config
    - availability_zone
    - config_drive
    - changes-since
    - created_at
    - deleted
    - description
    - display_description
    - display_name
    - flavor
    - host
    - hostname
    - image
    - image_ref
    - ip
    - ip6
    - kernel_id
    - key_name
    - launch_index
    - launched_at
    - limit
    - locked_by
    - marker
    - name
    - node
    - not-tags          (available in 2.26+)
    - not-tags-any      (available in 2.26+)
    - power_state
    - progress
    - project_id
    - ramdisk_id
    - reservation_id
    - root_device_name
    - sort_dir
    - sort_key
    - status
    - tags              (available in 2.26+)
    - tags-any          (available in 2.26+)
    - task_state
    - tenant_id
    - terminated_at
    - user_id
    - uuid
    - vm_state

    For non-admin users, there is a whitelist for filters already. That
    whitelist is unchanged.

    **Sorting**

    The whitelist for sort keys for admin users:

    - access_ip_v4
    - access_ip_v6
    - auto_disk_config
    - availability_zone
    - config_drive
    - created_at
    - display_description
    - display_name
    - host
    - hostname
    - image_ref
    - instance_type_id
    - kernel_id
    - key_name
    - launch_index
    - launched_at
    - locked_by
    - node
    - power_state
    - progress
    - project_id
    - ramdisk_id
    - root_device_name
    - task_state
    - terminated_at
    - updated_at
    - user_id
    - uuid
    - vm_state

    For non-admin users, the sort key ``host`` and ``node`` will be excluded.

    **Other**

    `HTTP Bad Request 400` will be returned for the filters/sort keys which
    are on joined tables or internal data model attributes. They would
    previously cause a `HTTP Server Internal Error 500`, namely:

    - block_device_mapping
    - info_cache
    - metadata
    - pci_devices
    - security_groups
    - services
    - system_metadata

    In order to maintain backward compatibility, filter and sort parameters
    which are not mapped to the REST API `servers` resource representation are
    ignored.