roles:
- [osd.0, osd.1, osd.2, client.0, mon.a, mgr.x]
- [osd.3, osd.4, osd.5, client.1, mon.b, mgr.y]
- [osd.6, osd.7, osd.8, client.2, mon.c, mgr.z]
- [osd.9, osd.10, osd.11, client.3, mon.d]
- [osd.12, osd.13, osd.14, client.4, mon.e]