ceph动态增加osd，增加的osd状态是down，怎样才能up？

centos7下ceph搭建好了后，我想要动态增加osd，增加的osd也都显示已经启动，如下：

     #/etc/init.d/ceph -a start

 === mon.0 ===
 Starting Ceph mon.0 on node56...already running   
 === mds.0 ===   
 Starting Ceph mds.0 on node56...already running   
 === osd.0 ===   
 Starting Ceph osd.0 on node57...already running   
 === osd.1 ===   
 Starting Ceph osd.1 on node58...already running   
 === osd.2 ===   
 Starting Ceph osd.2 on node57...already running   
 === osd.3 ===   
 Starting Ceph osd.3 on node58...already running   
 === osd.4 ===   
 Starting Ceph osd.4 on node56...already running 

但是查看osd的状态却是down，我使用/etc/init.d/ceph start osd.0，启动没出错，但是osd的状态还是down。怎么样才能把osd up？

    # ceph osd tree
    # id weight type name up/down reweight
-1 5 root default
-3 5 rack unknownrack
-2 1 host node57
0 1 osd.0 down 0 
-4 1 host node58
1 1 osd.1 down 0 
-5 3 host node56
4 1 osd.4 up 1 
2 1 osd.2 up 1 
3 1 osd.3 up 1

    # ceph df
GLOBAL:
    SIZE       AVAIL      RAW USED     %RAW USED 
    61410M     58299M        3110M          5.07 
POOLS:
    NAME         ID     USED     %USED     MAX AVAIL     OBJECTS 
    data         0         0         0             0           0 
    metadata     1      2082         0             0          20 
    rbd          2         0         0             0           0