某运营商的Kubernetes项目物理机停机维护，重启后Kubernetes部分pod无法挂载PVC，请求超时。该Kubernetes集群的后端存储使用ceph rbd块存储，检查ceph集群状态异常。
[root@ceph-node01~]# ceph -s
cluster:
id: 3c09c565-7421-411d-b9e0-5a370967556f
health: HEALTH_WARN
Reduced data availability: 12 pgs inactive, 12 pgs incomplete
12 slow ops, oldest one blocked for 5553 sec, daemons [osd.0,osd.3] have slow ops.
services:
mon: 3 daemons, quorum ceph-node01,ceph-node02,ceph-node03
mgr: mon_mgr(active)
osd: 9 osds: 9 up, 9 in
data:
pools: 3 pools, 512 pgs
objects: 64.26 k objects, 561 GiB
usage: 3.17 TiB used, 5.61 TiB / 8.78 TiB avail
pgs: 9.375% pgs not active
116 active+clean
12 incomplete
io:
client: 5.57MiB/s rd, 144KiB/s wr, 346op/s rd, 15op/s wr
集群检查提示PG_AVAILABILITY(数据可用性降低)，这说明群集无法满足群集中某些数据的潜在读取或写入请求。即有12个PG处于不允许为IO请求提供服务的状态。
PG检查
上面查看集群状态时，也可以发现pgs出现incomplete状态，执行health查看错误帮助。
[root@ceph-node01~]# ceph health detail
HEALTH_WARN Reduced data availability: 12 pgs inactive, 12 pgs incomplete; 12 slow ops, oldest one blocked for 5672 sec, daemons [osd.0,osd.3] have slow ops.
PG_AVAILABILITY Reduced data availability: 12 pgs inactive, 12 pgs incomplete
pg 1.1 is incomplete, acting [3,0]
pg 1.b is incomplete, acting [3,0]
pg 1.1b is incomplete, acting [3,0]
pg 1.2f is incomplete, acting [0,3]
pg 1.3a is incomplete, acting [3,0]
pg 1.40 is incomplete, acting [0,3]
pg 1.44 is incomplete, acting [0,3]
pg 1.47 is incomplete, acting [0,3]
pg 1.4d is incomplete, acting [0,3]
pg 1.5d is incomplete, acting [3,0]
pg 1.61 is incomplete, acting [0,3]
pg 1.66 is incomplete, acting [0,3]
pg Incomplete状态出现的原因大多是因为ceph集群在peering过程中，频繁重启服务器或断电。
启动osd或创建某个pg的时候,需要同步该pg上所有osd中的pg状态，这个过程叫做peering过程
Peering过程中， 由于
a. 无非选出权威日志
b. 通过choose_acting选出的Acting Set后续不足以完成数据修复，导致Peering无非正常完成
incomplete状态系统是无法自动复原的，需要手动修复
pg repair
Ceph提供了使用ceph pg repair命令修复不一致的PG
# ceph pg deep-scrub 11.eeef
instructing pg 11.eeef on osd.106 to deep-scrub
# ceph pg repair 11.eeef
instructing pg 11.eeef on osd.106 to repair
尝试使用 ceph pg repaire {pgid} 进行修复pg，但是无效。有些情况不应该通过ceph pg repair进行修复 ，当多副本数据存在不一致或主副本损坏导致的不一致时，是无法通过这个命令来完成修复的。
ceph_objectstore_tool
ceph-objectstore-tool是ceph提供的一个操作pg及pg里面的对象的高级工具。它能够对底层pg以及对象相关数据进行获取、修改。并能够对一些问题pg和对象进行简单修复。ceph-objectstore-tool的操作是不可逆的，执行修改操作前需要备份数据。
一般通过导出备份pg和导入pg，用于解决incomplete状态pg状态不对。
1、查看incomplete pg所在osd节点
[root@ceph-node01~]# ceph pg dump_stuck
ok
PG_STAT STATE UP UP_PRIMARY ACTING ACTING_PRIMARY
1.4d incomplete [0,3] 0 [0,3] 0
1.1b incomplete [3,0] 3 [3,0] 3
1.66 incomplete [0,3] 0 [0,3] 0
1.3a incomplete [3,0] 3 [3,0] 3
1.47 incomplete [0,3] 0 [0,3] 0
1.61 incomplete [0,3] 0 [0,3] 0
1.b incomplete [3,0] 3 [3,0] 3
1.40 incomplete [0,3] 0 [0,3] 0
1.5d incomplete [3,0] 3 [3,0] 3
1.1 incomplete [3,0] 3 [3,0] 3
1.2f incomplete [0,3] 0 [0,3] 0
1.44 incomplete [0,3] 0 [0,3] 0
2、停止要操作的osd时，否则会得到报错：OSD has the store locked
[root@ceph-node03~]# systemctl stop ceph-osd.target
3、导出pg和导入pg
[root@ceph-node03~]# ceph-objectstore-tool --data-path /var/lib/ceph/osd/ceph-02/ --journal-path /var/log/ceph/ --pgid 1.4d --op export --file 0.3
[root@ceph-node03~]# ceph-objectstore-tool --data-path /var/lib/ceph/osd/ceph-02/ --journal-path /var/log/ceph/ --op import --file 0.3
4、将pg标记为complete
[root@ceph-node03~]# ceph-objectstore-tool --data-path /var/lib/ceph/osd/ceph-02/ --journal-path /var/log/ceph/ --type filestore --pgid 1.4d --op mark-complete
WARNING: Ignoring type "filestore" - found data-path type "bluestore"
Marking complete
Marking complete succeeded
5、启动osd，osd启动后，检查osd进程是否存在，一般要等几分钟才能看到UP
[root@ceph-node03 ~]# systemctl start ceph-osd.target
[root@ceph-node03 ~]#
[root@ceph-node03 ~]# ceph osd tree
ID CLASS WEIGHT TYPE NAME STATUS REWEIGHT PRI-AFF
-1 0.02939 root default
-3 0.00980 host ceph-node01
0 hdd 0.00980 osd.0 down 1.00000 1.00000
-5 0.00980 host ceph-node02
2 hdd 0.00980 osd.2 up 1.00000 1.00000
-7 0.00980 host ceph-node03
3 hdd 0.00980 osd.3 down 1.00000 1.00000
集群开始自己恢复，这个过程可以看到“pgs:215/6240 objects degraded (3.446%)”一直在变化，直到集群状态正常。
[root@ceph-node03 ~]# ceph -s
cluster:
id: 3c09c565-7421-411d-b9e0-5a370967556f
health: HEALTH_OK
services:
mon: 3 daemons, quorum ceph-node01,ceph-node02,ceph-node03
mgr: mon_mgr(active)
osd: 9 osds: 9 up, 9 in
data:
pools: 3 pools, 512 pgs
objects: 64.26 k objects, 561 GiB
usage: 3.17 TiB used, 5.61 TiB / 8.78 TiB avail
pgs: 512 active+clean
io:
client: 341 B/s rd, 13 MiB/s wr, 0 op/s rd, 1.10 kop/s wr
优雅停止ceph
需要停机维护时，ceph一定要正常停止服务，尽量避免强制关机，拔电源等骚操作，物理机确认正常后再启动ceph，避免重复启动osd。
ceph osd set noout
ceph osd set nobackfill
ceph osd set norecover
systemctl stop ceph-mgr.target
systemctl stop ceph-mds.target
systemctl stop ceph-mon.target
systemctl stop ceph-radosgw.target
systemctl stop ceph-osd.target
