nfs进程变D故障处理
问题现象
客户端是opentack，通过nfs挂载我们存储，发现有个服务进程变D了，长时间无法恢复，如下
[root@ECM-043 ~]# ps aux|grep nova-compute
nova 21409 1.4 0.0 2117692 110916 ? Dl 15:06 1:24 /opt/server/python27/bin/python /usr/bin/nova-compute --logfile /var/log/nova/compute.log
#排查步骤
##客户端排查，查找该进程hang 在哪里，lsof 查找进程打开的文件
lsof -p 21409
nova-comp 21409 nova 22w REG 0,29 0 2199054015793 /var/lib/nova/instances/locks/nova-storage-registry-lock (block.beijing.wocloud.cn:/var/share/ezfs/shareroot/block-bj)
可以看到客户端的进程打开了nfs上的nova-storage-registry-lock文件，下一步在服务端看下该文件的状态
##服务端查看nova-storage-registry-lock 文件的inode号
知道了inode号，在所有的nfs服务端，看下是否有其他进程 拿着 该lock 文件
/proc/locks 各字段的含义见后面的延伸章节
root@Storage5:~# cat /proc/locks |grep inode
1: POSIX ADVISORY WRITE 28331 00:14:2199053494291 0 EOF
2: POSIX ADVISORY WRITE 28165 00:14:1099511627783 0 0
3: POSIX ADVISORY READ 360769 00:0f:21590 4 4
4: POSIX ADVISORY WRITE 28331 00:14:2199054015793 0 EOF
5: POSIX ADVISORY WRITE 1022761 00:0f:673303453 0 EOF
6: POSIX ADVISORY WRITE 98842 00:0f:47181 0 EOF
7: POSIX ADVISORY WRITE 688677 00:0f:1186403778 0 EOF
8: POSIX ADVISORY READ 38754 00:0f:21590 4 4
服务端 确认哪些 nfs客户端连接
nfs 是无状态协议，和cifs不一样，不是TCP 吗？
root@Storage5:/var/lib/nfs/sm# ll
total 48
drwxr-xr-x 2 statd root 4096 Apr 13 09:03 ./
drwxr-xr-x 5 statd root 4096 Apr 10 18:21 ../
-rw------- 1 statd root 88 Apr 11 16:08 10.55.4.1
-rw------- 1 statd root 89 Apr 10 14:47 10.55.4.15
-rw------- 1 statd root 89 Apr 10 14:41 10.55.4.16
-rw------- 1 statd root 90 Apr 7 02:10 10.55.4.199
-rw-r----- 1 statd root 1350 Apr 11 13:42 10.55.4.205
-rw------- 1 statd root 89 Apr 11 16:00 10.55.4.31
-rw------- 1 statd root 89 Apr 10 14:44 10.55.4.32
-rw------- 1 statd root 89 Apr 10 14:34 10.55.4.37
-rw------- 1 statd root 89 Apr 11 16:04 10.55.4.54
-rw-r----- 1 statd root 2288 Apr 13 09:03 10.55.4.9
root@Storage5:/var/lib/nfs/sm# pwd
/var/lib/nfs/sm
总结
会有多个客户端可能会同时访问这个所文件，存储端的ceph版本为0.67的版本，mds在并发访问控制上并不能处理所有异常。所以只能用一个临时的快速恢复的方法来处理，即删掉该 lock 文件，让客户端重新生成该lock文件。
延伸
linux下lock类型
文件锁，主要分为 flock 和fcntl
2者的粒度不一样 ###flock 锁住整个文件，如下，
root@scal61:/usr/share/pyshared/ezs3# cat /proc/locks
1: FLOCK ADVISORY WRITE 97862 00:12:229635 0 EOF
2: FLOCK(lock类型） ADVISORY（建议锁，非强制执行） WRITE（holder能写lock文件） 4246（holder的pid） 00:12:20704（锁文件的MAJOR-DEVICE:MINOR-DEVICE:INODE-NUMBER） 0 EOF（锁文件的范围，0到EOF代表整个文件）
###fcntl lock文件的某一部分，如下 posix
root@scal61:/usr/share/pyshared/ezs3# cat /proc/locks
3: POSIX ADVISORY WRITE 97830 08:03:524404 0 EOF
4: POSIX ADVISORY WRITE 4056 00:12:41028 0 EOF
5: POSIX ADVISORY READ 2351 00:12:10095 4 4
6: POSIX ADVISORY READ 2783 00:12:10052 4 4
7: POSIX ADVISORY READ 2783 00:12:14432 4 4
8: POSIX ADVISORY WRITE 2783 00:12:10050 0 0
*** centos
- FLOCK signifying the older-style UNIX file locks from a flock system call
- POSIX representing the newer POSIX locks from the lockf system call.
- ADVISORY means that the lock does not prevent other people from accessing the data; it only prevents other attempts to lock it
-
MANDATORY means that no other access to the data is permitted while the lock is held
- The fourth column reveals whether the lock is allowing the holder READ or WRITE access to the file
lsof 命令
lsof abc.txt 显示开启文件abc.txt的进程
lsof -i :22 知道22端口现在运行什么程序
lsof -c abc 显示abc进程现在打开的文件
lsof -g gid 显示归属gid的进程情况
lsof +d /usr/local/ 显示目录下被进程开启的文件
lsof +D /usr/local/ 同上，但是会搜索目录下的目录，时间较长
lsof -d 4 显示使用fd为4的进程
lsof -i 用以显示符合条件的进程情况
lsof 各字段
COMMAND PID TID USER FD TYPE DEVICE SIZE/OFF NODE NAME
init 1 root mem REG 8,1 134296 529350 /lib/x86_64-linux-gnu/libselinux.so.1
init 1 root mem REG 8,1 281552 529234 /lib/x86_64-linux-gnu/libdbus-1.so.3.7.6
node : 文件的inode
命令示例
lsof -p 5527
ceph-osd 5527 root *627w REG 252,0 282448 4196063 /data/cache/g-osd-0/current/18.137_head/omap/000471.log
root@converger-124:~#
root@converger-124:/proc/5527/fd# ll |grep /data/cache/g-osd-0/current/18.137_head/omap/000471.log
l-wx------ 1 root root 64 Jul 5 16:47 17627 -> /data/cache/g-osd-0/current/18.137_head/omap/000471.log
root@converger-124:/proc/5527/fd#
列出某个文件 被哪些进程在用
root@converger-124:/proc/5527/fd# lsof /data/cache/g-osd-0/current/18.137_head/omap/000471.log
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
ceph-osd 5527 root *627w REG 252,0 292839 4196063 /data/cache/g-osd-0/current/18.137_head/omap/000471.log
root@converger-124:/proc/5527/fd#
root@converger-124:/proc/5527/fd# stat /data/cache/g-osd-0/current/18.137_head/omap/000471.log
File: ‘/data/cache/g-osd-0/current/18.137_head/omap/000471.log’
Size: 294280 Blocks: 584 IO Block: 4096 regular file
Device: fc00h/64512d Inode: 4196063 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-07-05 10:18:30.376381600 +0800
Modify: 2019-07-05 17:02:33.030906129 +0800
Change: 2019-07-05 17:02:33.030906129 +0800
Birth: -
root@converger-124:/proc/5527/fd#
http://www.361way.com/lsof/176.html
##/proc/目录和ps 命令
lsof 命令有时候输出很慢，更快的方式就是 通过/proc 目录去快速 查找 进程的相关信息。ps 命令的输出也是通过读取/proc目录
/proc/5527/fd
fd目录列出了进程打开的文件
task目录列出了进程的子进程
ps 知识点记录
ps参数比较多，根据需要 显示进程的信息。比如进程的启动时间，运行时间，状态，
# 参数
参数 -e 显示所有进程信息，-o 参数控制输出。Pid,User 和 Args参数显示PID，运行应用的用户和该应用。
-u 显示用户进程
ps -efww //david 常用
UID PID PPID C STIME TTY TIME CMD
root 1 0 0 2016 ? 00:00:02 /sbin/init
root 2 0 0 2016 ? 00:00:00 [kthreadd]
ps -aux //bean
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 1 0.0 0.0 24588 1224 ? Ss 2016 0:02 /sbin/init
root 2 0.0 0.0 0 0 ? S 2016 0:00 [kthreadd]
ps -ef
UID PID PPID C STIME TTY TIME CMD
root 1 0 0 2016 ? 00:00:02 /sbin/init
root 2 0 0 2016 ? 00:00:00 [kthreadd]
root 3 2 0 2016 ? 00:34:18 [ksoftirqd/0]
ps -eF
UID PID PPID C SZ RSS PSR STIME TTY TIME CMD
root 1 0 0 6147 1224 11 2016 ? 00:00:02 /sbin/init
root 2 0 0 0 0 10 2016 ? 00:00:00 [kthreadd]
root 3 2 0 0 0 0 2016 ? 00:34:18 [ksoftirqd/0]
root 5 2 0 0 0 0 2016 ? 00:00:00 [kworker/0:0H]
PROCESS STATE CODES
Here are the different values that the s, stat and state output specifiers (header "STAT" or "S") will display to describe the state of a process:
D uninterruptible sleep (usually IO)
R running or runnable (on run queue)
S interruptible sleep (waiting for an event to complete)
T stopped, either by a job control signal or because it is being traced.
W paging (not valid since the 2.6.xx kernel)
X dead (should never be seen)
Z defunct ("zombie") process, terminated but not reaped by its parent.
For BSD formats and when the stat keyword is used, additional characters may be displayed:
< high-priority (not nice to other users)
N low-priority (nice to other users)
L has pages locked into memory (for real-time and custom IO)
s is a session leader
l is multi-threaded (using CLONE_THREAD, like NPTL pthreads do)
+ is in the foreground process group.
# 查看进程的线程
ps -eLf #L要大写，其中LWP ，light weighted process，代表thread
UID PID PPID LWP C NLWP STIME TTY TIME CMD
root 1 0 1 0 1 Oct30 ? 00:08:28 /sbin/init
root 2 0 2 0 1 Oct30 ? 00:03:56 [kthreadd]
root 3 2 3 0 1 Oct30 ? 00:20:07 [ksoftirqd/0]
root 5 2 5 0 1 Oct30 ? 00:00:00 [kworker/0:0H]
root 7 2 7 0 1 Oct30 ? 00:55:00 [rcu_sched]
root 8 2 8 0 1 Oct30 ? 00:00:00 [rcu_bh]
root 9 2 9 0 1 Oct30 ? 00:07:19 [migration/0]
root 10 2 10 0 1 Oct30 ? 00:00:04 [watchdog/0]
#查看 进程的 运行时间
root@BTDISK-12:~# ps -C atop -o etime,pid,cmd
ELAPSED PID CMD
00:29 654009 /usr/bin/atop -a -w /var/log/atop.log 600