Ralph,
The only time we use the resolved names is when we get a map, so we
consider them part of the map output.
If quasi-XML is all that will ever be possible with 1.3, then you may
as well leave as-is and we will attempt to clean it up in Eclipse. It
would be nice if a future version of ompi could output correct XML
(including stdout) as this would vastly simplify the parsing we need
to do.
Regards,
Greg
On Jan 13, 2009, at 3:30 PM, Ralph Castain wrote:
Hmmm...well, I can't do either for 1.3.0 as it is departing this
afternoon.
The first option would be very hard to do. I would have to expose
the display-map option across the code base and check it prior to
printing anything about resolving node names. I guess I should ask:
do you only want noderesolve statements when we are displaying the
map? Right now, I will output them regardless.
The second option could be done. I could check if any "display"
option has been specified, and output the <ompi> root at that time
(likewise for the end). Anything we output in-between would be
encapsulated between the two, but that would include any user output
to stdout and/or stderr - which for 1.3.0 is not in xml.
Any thoughts?
Ralph
PS. Guess I should clarify that I was not striving for true XML
interaction here, but rather a quasi-XML format that would help you
to filter the output. I have no problem trying to get to something
more formally correct, but it could be tricky in some places to
achieve it due to the inherent async nature of the beast.
On Jan 13, 2009, at 12:17 PM, Greg Watson wrote:
Ralph,
The XML is looking better now, but there is still one problem. To
be valid, there needs to be only one root element, but currently
you don't have any (or many). So rather than:
<noderesolve name="node0" resolved="Jarrah.local"/>
<noderesolve name="node1" resolved="Jarrah.local"/>
<map>
<host name="Jarrah.local" slots="8" max_slots="0">
<process rank="0"/>
<process rank="1"/>
<process rank="2"/>
<process rank="3"/>
<process rank="4"/>
</host>
</map>
the XML should be:
<map>
<noderesolve name="node0" resolved="Jarrah.local"/>
<noderesolve name="node1" resolved="Jarrah.local"/>
<host name="Jarrah.local" slots="8" max_slots="0">
<process rank="0"/>
<process rank="1"/>
<process rank="2"/>
<process rank="3"/>
<process rank="4"/>
</host>
</map>
or:
<ompi>
<noderesolve name="node0" resolved="Jarrah.local"/>
<noderesolve name="node1" resolved="Jarrah.local"/>
<map>
<host name="Jarrah.local" slots="8" max_slots="0">
<process rank="0"/>
<process rank="1"/>
<process rank="2"/>
<process rank="3"/>
<process rank="4"/>
</host>
</map>
</ompi>
Would either of these be possible?
Thanks,
Greg
On Dec 8, 2008, at 2:18 PM, Greg Watson wrote:
Ok thanks. I'll test from trunk in future.
Greg
On Dec 8, 2008, at 2:05 PM, Ralph Castain wrote:
Working its way around the CMR process now.
Might be easier in the future if we could test/debug this in the
trunk, though. Otherwise, the CMR procedure will fall behind and
a fix might miss a release window.
Anyway, hopefully this one will make the 1.3.0 release cutoff.
Thanks
Ralph
On Dec 8, 2008, at 9:56 AM, Greg Watson wrote:
Hi Ralph,
This is now in 1.3rc2, thanks. However there are a couple of
problems. Here is what I see:
[Jarrah.watson.ibm.com:58957] <noderesolve name="node0"
resolved="Jarrah.watson.ibm.com">
For some reason each line is prefixed with "[...]", any idea why
this is? Also the end tag should be "/>" not ">".
Thanks,
Greg
On Nov 24, 2008, at 3:06 PM, Greg Watson wrote:
Great, thanks. I'll take a look once it comes over to 1.3.
Cheers,
Greg
On Nov 24, 2008, at 2:59 PM, Ralph Castain wrote:
Yo Greg
This is in the trunk as of r20032. I'll bring it over to 1.3
in a few days.
I implemented it as another MCA param
"orte_show_resolved_nodenames" so you can actually get the
info as you execute the job, if you want. The xml tag is
"noderesolve" - let me know if you need any changes.
Ralph
On Oct 22, 2008, at 11:55 AM, Greg Watson wrote:
Ralph,
I guess the issue for us is that we will have to run two
commands to get the information we need. One to get the
configuration information, such as version and MCA
parameters, and one to get the host information, whereas it
would seem more logical that this should all be available via
some kind of "configuration discovery" command. I understand
the issue with supplying the hostfile though, so maybe this
just points at the need for us to separate configuration
information from the host information. In any case, we'll
work with what you think is best.
Greg
On Oct 20, 2008, at 4:49 PM, Ralph Castain wrote:
Hmmm...just to be sure we are all clear on this. The reason
we proposed to use mpirun is that "hostfile" has no meaning
outside of mpirun. That's why ompi_info can't do anything in
this regard.
We have no idea what hostfile the user may specify until we
actually get the mpirun cmd line. They may have specified a
default-hostfile, but they could also specify hostfiles for
the individual app_contexts. These may or may not include
the node upon which mpirun is executing.
So the only way to provide you with a separate command to
get a hostfile<->nodename mapping would require you to
provide us with the default-hostifle and/or hostfile cmd
line options just as if you were issuing the mpirun cmd. We
just wouldn't launch - but it would be the exact equivalent
of doing "mpirun --do-not-launch".
Am I missing something? If so, please do correct me - I
would be happy to provide a tool if that would make it
easier. Just not sure what that tool would do.
Thanks
Ralph
On Oct 19, 2008, at 1:59 PM, Greg Watson wrote:
Ralph,
It seems a little strange to be using mpirun for this, but
barring providing a separate command, or using ompi_info, I
think this would solve our problem.
Thanks,
Greg
On Oct 17, 2008, at 10:46 AM, Ralph Castain wrote:
Sorry for delay - had to ponder this one for awhile.
Jeff and I agree that adding something to ompi_info would
not be a good idea. Ompi_info has no knowledge or
understanding of hostfiles, and adding that capability to
it would be a major distortion of its intended use.
However, we think we can offer an alternative that might
better solve the problem. Remember, we now treat hostfiles
in a very different manner than before - see the wiki page
for a complete description, or "man orte_hosts".
So the problem is that, to provide you with what you want,
we need to "dump" the information from whatever default-
hostfile was provided, and, if no default-hostfile was
provided, then the information from each hostfile that was
provided with an app_context.
The best way we could think of to do this is to add
another mpirun cmd line option --dump-hostfiles that would
output the line-by-line name from the hostfile plus the
name we resolved it to. Of course, --xml would cause it to
be in xml format.
Would that meet your needs?
Ralph
On Oct 15, 2008, at 3:12 PM, Greg Watson wrote:
Hi Ralph,
We've been discussing this back and forth a bit
internally and don't really see an easy solution. Our
problem is that Eclipse is not running on the head node,
so gethostbyname will not necessarily resolve to the same
address. For example, the hostfile might refer to the
head node by an internal network address that is not
visible to the outside world. Since gethostname also
looks in /etc/hosts, it may resolve locally but not on a
remote system. The only think I can think of would be,
rather than us reading the hostfile directly as we do
now, to provide an option to ompi_info that would dump
the hostfile using the same rules that you apply when
you're using the hostfile. Would that be feasible?
Greg
On Sep 22, 2008, at 4:25 PM, Ralph Castain wrote:
Sorry for delay - was on vacation and am now trying to
work my way back to the surface.
I'm not sure I can fix this one for two reasons:
1. In general, OMPI doesn't really care what name is
used for the node. However, the problem is that it needs
to be consistent. In this case, ORTE has already used
the name returned by gethostname to create its session
directory structure long before mpirun reads a hostfile.
This is why we retain the value from gethostname instead
of allowing it to be overwritten by the name in whatever
allocation we are given. Using the name in hostfile
would require that I either find some way to remember
any prior name, or that I tear down and rebuild the
session directory tree - neither seems attractive nor
simple (e.g., what happens when the user provides
multiple entries in the hostfile for the node, each with
a different IP address based on another interface in
that node? Sounds crazy, but we have already seen it
done - which one do I use?).
2. We don't actually store the hostfile info anywhere -
we just use it and forget it. For us to add an XML
attribute containing any hostfile-related info would
therefore require us to re-read the hostfile. I could
have it do that -only- in the case of "XML output
required", but it seems rather ugly.
An alternative might be for you to simply do a
"gethostbyname" lookup of the IP address or hostname to
see if it matches instead of just doing a strcmp. This
is what we have to do internally as we frequently have
problems with FQDN vs. non-FQDN vs. IP addresses etc. If
the local OS hasn't cached the IP address for the node
in question it can take a little time to DNS resolve it,
but otherwise works fine.
I can point you to the code in OPAL that we use - I
would think something similar would be easy to implement
in your code and would readily solve the problem.
Ralph
On Sep 19, 2008, at 7:18 AM, Greg Watson wrote:
Ralph,
The problem we're seeing is just with the head node. If
I specify a particular IP address for the head node in
the hostfile, it gets changed to the FQDN when
displayed in the map. This is a problem for us as we
need to be able to match the two, and since we're not
necessarily running on the head node, we can't always
do the same resolution you're doing.
Would it be possible to use the same address that is
specified in the hostfile, or alternatively provide an
XML attribute that contains this information?
Thanks,
Greg
On Sep 11, 2008, at 9:06 AM, Ralph Castain wrote:
Not in that regard, depending upon what you mean by
"recently". The only changes I am aware of wrt nodes
consisted of some changes to the order in which we use
the nodes when specified by hostfile or -host, and a
little #if protectionism needed by Brian for the Cray
port.
Are you seeing this for every node? Reason I ask: I
can't offhand think of anything in the code base that
would replace a host name with the FQDN because we
don't get that info for remote nodes. The only
exception is the head node (where mpirun sits) - in
that lone case, we default to the name returned to us
by gethostname(). We do that because the head node is
frequently accessible on a more global basis than the
compute nodes - thus, the FQDN is required to ensure
that there is no address confusion on the network.
If the user refers to compute nodes in a hostfile or -
host (or in an allocation from a resource manager) by
non-FQDN, we just assume they know what they are doing
and the name will correctly resolve to a unique address.
On Sep 10, 2008, at 9:45 AM, Greg Watson wrote:
Hi,
Has there been a change in the behavior of the -
display-map option has changed recently in the 1.3
branch. We're now seeing the host name as a fully
resolved DN rather than the entry that was specified
in the hostfile. Is there any particular reason for
this? If so, would it be possible to add the hostfile
entry to the output since we need to be able to match
the two?
Thanks,
Greg
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