roles:
- - mon.a
  - mgr.y
  - osd.0
  - client.0
  - ceph.rgw.foo.a
  - node-exporter.a
  - alertmanager.a
- - mon.b
  - mgr.x
  - osd.1
  - client.1
  - prometheus.a
  - grafana.a
  - node-exporter.b
- - mon.c
  - mgr.z
  - osd.2
  - client.2
  - node-exporter.c
openstack:
- volumes: # attached to each instance
    count: 1
    size: 10 # GB
overrides:
  ceph:
    conf:
      osd:
        osd shutdown pgref assert: true