Comment 1 for bug 1756363

I tried instead of overriding ExtraConfig in an additional environment file to remove the old hieradata from the existing environment file and this allowed me to move forward.

Original Environment file containing hiera:

parameter_defaults:
    CinderEnableIscsiBackend: false
    CinderEnableRbdBackend: true
    CinderEnableNfsBackend: false
    NovaEnableRbdBackend: true
    GlanceBackend: rbd
    CinderRbdPoolName: "volumes"
    NovaRbdPoolName: "vms"
    GlanceRbdPoolName: "images"
    ExtraConfig:
      ceph::profile::params::osd_pool_default_pg_num: 32
      ceph::profile::params::osd_pool_default_pgp_num: 32
      ceph::profile::params::osds:
       '/dev/vdb': {}

Adjusted file used during upgrade which allows the upgrade to pass:

parameter_defaults:
    CinderEnableIscsiBackend: false
    CinderEnableRbdBackend: true
    CinderEnableNfsBackend: false
    NovaEnableRbdBackend: true
    GlanceBackend: rbd
    CinderRbdPoolName: "volumes"
    NovaRbdPoolName: "vms"
    GlanceRbdPoolName: "images"
    ExtraConfig: {}
    CephPoolDefaultPgNum: 32
    CephAnsibleDisksConfig:
        devices:
            - '/dev/vdb'