[mpich-discuss] open failed for root's mpd conf

Dave Goodell goodell at mcs.anl.gov
Wed Mar 17 17:20:42 CDT 2010 

Oops, I omitted something important from that strace command.  It  
should read like this instead:

-----8<-----
strace -f -e trace=file mpiexec echo foo 2>&1 | grep mpd.conf
-----8<-----

-Dave

On Mar 17, 2010, at 5:10 PM, Dave Goodell wrote:

> OK, I suppose that theory didn't pan out.
>
> You could try something like the following to see why the open for "/ 
> etc/mpd.conf" is failing, but you will need a setuid root version of  
> strace:
>
> -----8<-----
> strace -f -e trace=file 2>&1 | grep mpd.conf
> -----8<-----
>
> I don't remember exactly how to get a proper setuid strace  
> installation, although it may be as simple as "sudo chmod u+s /path/ 
> to/strace ; sudo chown root /path/to/strace".  Please be aware that  
> allowing arbitrary users to execute setuid root strace is a *huge*  
> local security hole.  So if this is a multi-user system then you  
> should restrict execution to users in a trusted group and only mess  
> around with this on a copy of the file.  See the strace man page if  
> you want to go down this path.
>
> Or just run the mpd ring as your user.  I wouldn't personally  
> recommend running something as fragile as mpd as root anyway, even  
> though it is technically possible.
>
> Alternatively, ditch mpd altogether and try the hydra process  
> manager: http://wiki.mcs.anl.gov/mpich2/index.php/Using_the_Hydra_Process_Manager
>
> It doesn't require setting up any daemons in the common case.
>
> -Dave
>
> On Mar 17, 2010, at 4:51 PM, rcx11 at yahoo.com wrote:
>
>> Output of "strings /usr/bin/mpdroot | grep etc" yielded "/etc/ 
>> mpd.conf" Setting the environment variable failed. I made a symlink  
>> to /etc/mpd.conf in /usr/etc/mpd.conf. This also failed.
>>
>> --- On Wed, 3/17/10, Dave Goodell <goodell at mcs.anl.gov> wrote:
>>
>>> From: Dave Goodell <goodell at mcs.anl.gov>
>>> Subject: Re: [mpich-discuss] open failed for root's mpd conf
>>> To: mpich-discuss at mcs.anl.gov
>>> Date: Wednesday, March 17, 2010, 4:33 PM
>>> Well, if my earlier suggestion about
>>> "/etc/mpd.conf" doesn't solve the problem, then I am not
>>> entirely sure what is going on.
>>>
>>> I just took a peek at the code and it looks like we may
>>> have a bug in the root mpd.conf search path that was
>>> introduced in r5844.  We now search
>>> "@sysconfdir@/mpd.conf" (which expands to
>>> "${prefix}/etc/mpd.conf" normally) instead of
>>> "/etc/mpd.conf".  So I'm betting that you have a valid
>>> "/etc/mpd.conf" but mpdroot is looking for it in
>>> "/usr/etc/mpd.conf" instead.
>>>
>>> Can you try two things for me?  First run the
>>> following command and send us the output: "strings
>>> /usr/bin/mpdroot | grep etc".  Second, try setting the
>>> environment variable "MPD_CONF_FILE=/etc/mpd.conf" before
>>> running mpiexec.  That may let you work around the
>>> problem for now.  Alternatively you could probably move
>>> your "/etc/mpd.conf" to the "/usr/etc/" directory.
>>>
>>> -Dave
>>>
>>> On Mar 17, 2010, at 3:59 PM, rcx11 at yahoo.com
>>> wrote:
>>>
>>>> That is exactly what I'm trying to do - run on a root
>>> started ring as a normal user. I get no errors when running
>>> as root.
>>>>
>>>> --- On Wed, 3/17/10, Dave Goodell <goodell at mcs.anl.gov>
>>> wrote:
>>>>
>>>>> From: Dave Goodell <goodell at mcs.anl.gov>
>>>>> Subject: Re: [mpich-discuss] open failed for
>>> root's mpd conf
>>>>> To: mpich-discuss at mcs.anl.gov
>>>>> Date: Wednesday, March 17, 2010, 3:46 PM
>>>>> Just to be sure, you are trying to to
>>>>> use a root-started mpd ring as a
>>>>> regular user, correct?  If so, make sure that
>>> you have
>>>>> a mode 600 file
>>>>> named "/etc/mpd.conf" (no leading ".") containing
>>> the
>>>>> secret word.
>>>>>
>>>>> If you are trying to use a regular user-started
>>> mpd ring as
>>>>> a regular
>>>>> user, then remove "MPD_USE_ROOT_MPD=yes" from
>>> your
>>>>> "~/.mpd.conf".
>>>>>
>>>>> -Dave
>>>>>
>>>>> On Mar 17, 2010, at 3:33 PM, rcx11 at yahoo.com
>>>>> wrote:
>>>>>
>>>>>> It's "MPD_USE_ROOT_MPD=yes" as per setup guide
>>> in the
>>>>> link given.
>>>>>>
>>>>>> --- On Wed, 3/17/10, Dave Goodell <goodell at mcs.anl.gov>
>>>>> wrote:
>>>>>>
>>>>>>> From: Dave Goodell <goodell at mcs.anl.gov>
>>>>>>> Subject: Re: [mpich-discuss] open failed
>>> for
>>>>> root's mpd conf
>>>>>>> To: mpich-discuss at mcs.anl.gov
>>>>>>> Date: Wednesday, March 17, 2010, 3:02 PM
>>>>>>> On Mar 17, 2010, at 2:50 PM, rcx11 at yahoo.com
>>>>>>> wrote:
>>>>>>>
>>>>>>>> I've been searching through
>>> documentation
>>>>> trying to
>>>>>>> find why I'm getting the error when trying
>>> to run
>>>>> as a
>>>>>>> non-root user. I'm running Fedora 12 x86
>>> and have
>>>>> installed
>>>>>>> MPICH2 via yum. I've got my mpd.conf files
>>> created
>>>>> according
>>>>>>> to http://debianclusters.cs.uni.edu/index.php/MPICH_without_Torque_Functionality
>>>>>
>>>>>>> .
>>>>>>> When trying to run mpiexec as a non-root
>>> user, I
>>>>> get the
>>>>>>> error "/usr/bin/mpdroot: open failed for
>>> root's
>>>>> mpd conf
>>>>>>> filempiexec_sebastian.ags-rolla.zapto.org
>>>>> (__init__ 1208):
>>>>>>> forked process failed; status=255" What is
>>> causing
>>>>> this?
>>>>>>>
>>>>>>> Please see section 5.1.6 of the
>>> Installer's Guide:
>>>>> http://www.mcs.anl.gov/research/projects/mpich2/documentation/files/mpich2-1.2.1-installguide.pdf
>>>>>>>
>>>>>>> Do you have "MPD_USE_ROOT_MPD=1" set
>>> somewhere in
>>>>> your
>>>>>>> environment or mpd.conf file?
>>>>>>>
>>>>>>> -Dave
>>>>>>>
>>>>>>>
>>> _______________________________________________
>>>>>>> mpich-discuss mailing list
>>>>>>> mpich-discuss at mcs.anl.gov
>>>>>>> https://lists.mcs.anl.gov/mailman/listinfo/mpich-discuss
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
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