---
features:
  - |
    Microversion 2.49 brings device role tagging to the attach operation of
    volumes and network interfaces. Both network interfaces and volumes can now
    be attached with an optional ``tag`` parameter. The tag is then exposed to
    the guest operating system through the metadata API. Unlike the original
    device role tagging feature, tagged attach does not support the config
    drive. Because the config drive was never designed to be dynamic, it only
    contains device tags that were set at boot time with API 2.32. Any changes
    made to tagged devices with API 2.49 while the server is running will only
    be reflected in the metadata obtained from the metadata API. Because of
    metadata caching, changes may take up to ``metadata_cache_expiration`` to
    appear in the metadata API. The default value for
    ``metadata_cache_expiration`` is 15 seconds.

    Tagged volume attachment is not supported for shelved-offloaded instances.
    Tagged device attachment (both volumes and network interfaces) is not
    supported for Cells V1 deployments.