---
features:
  - |
    The libvirt driver now supports booting instances with virtual persistent
    memory (vPMEM), also called persistent memory (PMEM) namespaces.
    To enable vPMEM support, the user should specify the PMEM namespaces
    in the ``nova.conf`` by using the configuration option
    ``[libvirt]/pmem_namespaces``. For example::

      [libvirt]
      # pmem_namespaces=$LABEL:$NSNAME[|$NSNAME][,$LABEL:$NSNAME[|$NSNAME]]
      pmem_namespaces = 128G:ns0|ns1|ns2|ns3,262144MB:ns4|ns5,MEDIUM:ns6|ns7

    Only PMEM namespaces listed in the configuration file can be used by
    instances. To identify the available PMEM namespaces on the host or create
    new namespaces, the ``ndctl`` utility can be used::

      ndctl create-namespace -m devdax -s $SIZE -M mem -n $NSNAME

    Nova will invoke this utility to identify available PMEM namespaces.
    Then users can specify vPMEM resources in a flavor by adding flavor's
    extra specs::

      openstack flavor set --property hw:pmem=6GB,64GB <flavor-id>
