Hi,
   I reproduced this issue, and I believe it's a python bug.
   1. How to reproduce:
   with the test case attached, put it under /usr/share/vdsm/tests/, run #./run_tests.sh superVdsmTests.py
   and this issue will be reproduced.
   2.Log analyse:
   We notice a strange pattern in this log: connectStorageServer be called twice, first supervdsm call succeed, second fails becasue of  validateAccess().
   That is because for the first call validateAccess returns normally and leave a child there, when the second validateAccess call arrives and multirprocessing manager is receiving the method message, it is just the time first child exit and SIGCHLD comming, this signal interrupted multiprocessing receive system call, python managers.py should handle INTR and retry recv() like we do in vdsm but it's not, so the second one raise error.
>Thread-18::DEBUG::2013-01-22 10:41:03,570::misc::85::Storage.Misc.excCmd::(<lambda>) '/usr/bin/sudo -n /bin/mount -t nfs -o soft,nosharecache,timeo=600,retrans=6,nfsvers=3 192.168.0.1:/ovirt/silvermoon /rhev/data-center/mnt/192.168.0.1:_ovirt_silvermoon' (cwd None)
>Thread-18::DEBUG::2013-01-22 10:41:03,607::misc::85::Storage.Misc.excCmd::(<lambda>) '/usr/bin/sudo -n /bin/mount -t nfs -o soft,nosharecache,timeo=600,retrans=6,nfsvers=3 192.168.0.1:/ovirt/undercity /rhev/data-center/mnt/192.168.0.1:_ovirt_undercity' (cwd None)
>Thread-18::ERROR::2013-01-22 10:41:03,627::hsm::2215::Storage.HSM::(connectStorageServer) Could not connect to storageServer
>Traceback (most recent call last):
>  File "/usr/share/vdsm/storage/hsm.py", line 2211, in connectStorageServer
>    conObj.connect()
>  File "/usr/share/vdsm/storage/storageServer.py", line 303, in connect
>    return self._mountCon.connect()
>  File "/usr/share/vdsm/storage/storageServer.py", line 209, in connect
>    fileSD.validateDirAccess(self.getMountObj().getRecord().fs_file)
>  File "/usr/share/vdsm/storage/fileSD.py", line 55, in validateDirAccess
>    (os.R_OK | os.X_OK))
>  File "/usr/share/vdsm/supervdsm.py", line 81, in __call__
>    return callMethod()
>  File "/usr/share/vdsm/supervdsm.py", line 72, in <lambda>
>    **kwargs)
>  File "<string>", line 2, in validateAccess
>  File "/usr/lib64/python2.6/multiprocessing/managers.py", line 740, in _callmethod
>    raise convert_to_error(kind, result) 
the vdsm side receive RemoteError because of supervdsm server multiprocessing manager raise error KIND='TRACEBACK'
 >RemoteError: 
The upper part is the trace back from the client side, the following part is from server side:
>---------------------------------------------------------------------------
>Traceback (most recent call last):
>  File "/usr/lib64/python2.6/multiprocessing/managers.py", line 214, in serve_client
>    request = recv()
>IOError: [Errno 4] Interrupted system call
>---------------------------------------------------------------------------

Corresponding Python source code:managers.py(Server side)
    def serve_client(self, conn):
        '''
        Handle requests from the proxies in a particular process/thread
        '''
        util.debug('starting server thread to service %r',
                   threading.current_thread().name)
        recv = conn.recv
        send = conn.send
        id_to_obj = self.id_to_obj
        while not self.stop:
            try:
                methodname = obj = None
                request = recv()<------------------this line been interrupted by SIGCHLD
                ident, methodname, args, kwds = request
                obj, exposed, gettypeid = id_to_obj[ident]
                if methodname not in exposed:
                    raise AttributeError(
                        'method %r of %r object is not in exposed=%r' %
                        (methodname, type(obj), exposed)
                        )
                function = getattr(obj, methodname)
                try:
                    res = function(*args, **kwds)
                except Exception, e:
                    msg = ('#ERROR', e)
                else:
                    typeid = gettypeid and gettypeid.get(methodname, None)
                    if typeid:
                        rident, rexposed = self.create(conn, typeid, res)
                        token = Token(typeid, self.address, rident)
                        msg = ('#PROXY', (rexposed, token))
                    else:
                        msg = ('#RETURN', res)
            except AttributeError:
                if methodname is None:
                    msg = ('#TRACEBACK', format_exc())
                else:
                    try:
                        fallback_func = self.fallback_mapping[methodname]
                        result = fallback_func(
                            self, conn, ident, obj, *args, **kwds
                            )
                        msg = ('#RETURN', result)
                    except Exception:
                        msg = ('#TRACEBACK', format_exc())

            except EOFError:
                util.debug('got EOF -- exiting thread serving %r',
                           threading.current_thread().name)
                sys.exit(0)

            except Exception:<------does not handle IOError,INTR here should retry recv() 
                msg = ('#TRACEBACK', format_exc())


3. Actions we will take:
(1)As a work round we can first remove the zombie reaper from supervdsm server
(2)I'll see whether python has a fixed version for this
(3)Yaniv is working on changing vdsm/svdsm communication channel to pipe and handle it ourselves, I believe we'll get rid of this with that properly handled.


-------- Original Message --------
Subject: Re: [Users] latest vdsm cannot read ib device speeds causing storage attach fail
Resent-Date: Thu, 24 Jan 2013 12:24:10 +0200
Resent-From: Dan Kenigsberg <danken@redhat.com>
Resent-To: Royce Lv <lvroyce@linux.vnet.ibm.com>
Date: Wed, 23 Jan 2013 10:44:57 -0600
From: Dead Horse <deadhorseconsulting@gmail.com>
To: Dan Kenigsberg <danken@redhat.com>
CC: <users@ovirt.org> <users@ovirt.org>


VDSM was built from:
commit 166138e37e75767b32227746bb671b1dab9cdd5e

Attached is the full vdsm log

I should also note that from engine perspective it sees the master storage
domain as locked and the others as unknown.


On Wed, Jan 23, 2013 at 2:49 AM, Dan Kenigsberg <danken@redhat.com> wrote:

> On Tue, Jan 22, 2013 at 04:02:24PM -0600, Dead Horse wrote:
> > Any ideas on this one? (from VDSM log):
> > Thread-25::DEBUG::2013-01-22
> > 15:35:29,065::BindingXMLRPC::914::vds::(wrapper) client
> [3.57.111.30]::call
> > getCapabilities with () {}
> > Thread-25::ERROR::2013-01-22 15:35:29,113::netinfo::159::root::(speed)
> > cannot read ib0 speed
> > Traceback (most recent call last):
> >   File "/usr/lib64/python2.6/site-packages/vdsm/netinfo.py", line 155, in
> > speed
> >     s = int(file('/sys/class/net/%s/speed' % dev).read())
> > IOError: [Errno 22] Invalid argument
> >
> > Causes VDSM to fail to attach storage
>
> I doubt that this is the cause of the failure, as vdsm has always
> reported "0" for ib devices, and still is.
>
> Does a former version works with your Engine?
> Could you share more of your vdsm.log? I suppose the culprit lies in one
> one of the storage-related commands, not in statistics retrieval.
>
> >
> > Engine side sees:
> > ERROR [org.ovirt.engine.core.bll.storage.NFSStorageHelper]
> > (QuartzScheduler_Worker-96) [553ef26e] The connection with details
> > 192.168.0.1:/ovirt/ds failed because of error code 100 and error message
> > is: general exception
> > 2013-01-22 15:35:30,160 INFO
> > [org.ovirt.engine.core.bll.SetNonOperationalVdsCommand]
> > (QuartzScheduler_Worker-96) [1ab78378] Running command:
> > SetNonOperationalVdsCommand internal: true. Entities affected :  ID:
> > 8970b3fe-1faf-11e2-bc1f-00151712f280 Type: VDS
> > 2013-01-22 15:35:30,200 INFO
> > [org.ovirt.engine.core.vdsbroker.SetVdsStatusVDSCommand]
> > (QuartzScheduler_Worker-96) [1ab78378] START,
> > SetVdsStatusVDSCommand(HostName = kezan, HostId =
> > 8970b3fe-1faf-11e2-bc1f-00151712f280, status=NonOperational,
> > nonOperationalReason=STORAGE_DOMAIN_UNREACHABLE), log id: 4af5c4cd
> > 2013-01-22 15:35:30,211 INFO
> > [org.ovirt.engine.core.vdsbroker.SetVdsStatusVDSCommand]
> > (QuartzScheduler_Worker-96) [1ab78378] FINISH, SetVdsStatusVDSCommand,
> log
> > id: 4af5c4cd
> > 2013-01-22 15:35:30,242 ERROR
> > [org.ovirt.engine.core.dal.dbbroker.auditloghandling.AuditLogDirector]
> > (QuartzScheduler_Worker-96) [1ab78378] Try to add duplicate audit log
> > values with the same name. Type: VDS_SET_NONOPERATIONAL_DOMAIN. Value:
> > storagepoolname
> >
> > Engine = latest master
> > VDSM = latest master
>
> Since "latest master" is an unstable reference by definition, I'm sure
> that History would thank you if you post the exact version (git hash?)
> of the code.
>
> > node = el6
>
>