[tahoe-lafs-trac-stream] [tahoe-lafs] #1524: twistd can fail when checking whether a twistd.pid is stale

[tahoe-lafs]

#1524: twistd can fail when checking whether a twistd.pid is stale
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 Reporter:  davidsarah                           |          Owner:
     Type:  defect                               |         Status:  new
 Priority:  major                                |      Milestone:
Component:  code-nodeadmin                       |  undecided
 Keywords:  twistd reliability usability tahoe-  |        Version:  1.9.0a1
  start unix                                     |  Launchpad Bug:
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 After a failed hibernate/restore, I tried to restart some Tahoe nodes:
 {{{
 davidsarah at shinier:~/tahoe/1.9alpha$ bin/tahoe start ../grid/server1
 STARTING '/home/davidsarah/tahoe/grid/server1'
 Removing stale pidfile /home/davidsarah/tahoe/grid/server1/twistd.pid

 davidsarah at shinier:~/tahoe/1.9alpha$ bin/tahoe start ../grid/server2
 STARTING '/home/davidsarah/tahoe/grid/server2'
 Can't check status of PID 2015 from pidfile
 /home/davidsarah/tahoe/grid/server2/twistd.pid: Operation not permitted

 davidsarah at shinier:~/tahoe/1.9alpha$ ps -Fp 2015
 UID        PID  PPID  C    SZ   RSS PSR STIME TTY          TIME CMD

 davidsarah at shinier:~/tahoe/1.9alpha$ bin/tahoe start ../grid/server2
 STARTING '/home/davidsarah/tahoe/grid/server2'
 Can't check status of PID 2015 from pidfile
 /home/davidsarah/tahoe/grid/server2/twistd.pid: Operation not permitted

 davidsarah at shinier:~/tahoe/1.9alpha$ ls -l ../grid/server2/twistd.pid
 -rw-r--r-- 1 davidsarah davidsarah 4 2011-09-02 03:32
 ../grid/server2/twistd.pid

 davidsarah at shinier:~/tahoe/1.9alpha$ cat -v ../grid/server2/twistd.pid
 2015
 }}}

 There was no process with pid 2015. (Note that the {{{ps}}} command would
 show a process owned by another user including root.) I don't know why
 twistd is able to remove some stale pidfiles but not others.

 The problem can be worked around by removing the {{{twistd.pid}}} file,
 but that's not really very satisfactory.

 I'll file a bug against Twisted when I've investigated further.

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Ticket URL: <http://tahoe-lafs.org/trac/tahoe-lafs/ticket/1524>
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