1 2 3 4 5 6 7 8 9 10
roles: - [mon.a, mds.a, osd.0] - [mon.b, mgr.x, osd.1] - [mon.c, osd.2] - [osd.3] - [osd.4] - [osd.5] - [osd.6] - [osd.7] - [client.0]