---
features:
  - |
    The ``ironic-conductor`` process now has a concept of an internal
    memory limit. The intent of this is to prevent the conductor from running
    the host out of memory when a large number of deployments have been
    requested.

    These settings can be tuned using
    ``[DEFAULT]minimum_required_memory``,
    ``[DEFAULT]mimimum_memory_wait_time``,
    ``[DEFAULT]minimum_memory_wait_retries``, and
    ``[DEFAULT]minimum_memory_warning_only``.

    Where possible, Ironic will attempt to wait out the time window, thus
    consuming the conductor worker thread which will resume if the memory
    becomes available. This will effectively rate limit concurrency.

    If raw image conversions with-in the conductor is required, and a
    situation exists where insufficent memory exists and it cannot be waited,
    the deployment operation will fail. For the ``iscsi`` deployment
    interface, which is the other location in ironic that may consume large
    amounts of memory, the conductor will wait until the next agent heartbeat.
