On 06/26/2014 10:36 AM, Prentice Bisbal wrote:
I disagree with needed separate images in a VM/Docker/etc. environment,
maybe if your doing system-level research, but most HPC users work
exclusively in the user-space,and just want to run their
MATLAB/NAMD/LAMMPS, whatever job. In this case, just installing
user-space applications and libraries in a different path from the
distro-supplied versions is adequate. Modifying PATH and a few other
Not always ... I've seen library level collisions, where MKL runtime is
supplied per node/OS, and the application assumes different versions.
Similar for OpenMPI, HPMPI, IB, ...
This is where Docker shines. Its a container, not a full VM. Install
what you need, and don't worry about stuff you don't.
Or run your machine as an entire container (e.g. diskless/ramdisk root),
and solve the problem the same way.
environment variables that most users can handle is all you need
modules, lmod, softenv and other utilities make that even easier for users.
Sometimes ... Not all the time. Limited sets of apps will play well
with this. Just start playing with things that assume that the first
thing they find in the path named 'java' is the "right" one. Or the
first library in the tree managed by ld.so ...
The word 'nightmare' does not even begin to describe the debugging
process for this. Usually under the gun, with users needing the system
operational for their needs in time scales measured in minutes at most.
Been there, done that, which is why things that completely solve the
issue (e.g. shift the problem back to the user and their code) are a
good thing.
If you're doing lower-level research involving kernel modules or kernel
tuning, yes, you will need VMs or something. But this is usually
'research', not 'production' HPC.
I ended up doing very crazy root-stealing, chroot-establishing things
to get my science done in my PhD. If you prevent intelligent people
from doing their work, they are going to be your worst nightmare.
Don't kid yourselves if you think you are doing anyone favors by
providing super-static OS environments like RHEL for your users. You
are just being lazy (and not the good kind of programmer lazy).
This is so true. If you are a roadblock to your users, they will find a
way around you.
I was trying not to say that, as it alarms the people whom are steadfast
in their belief in the "one true way" to deliver these services, but ...
there is significant truth to this.
Put another way, then entire concept of beowulfery grew up around people
dissatisfied with the diktat from on high on how to purchase/build/run
their computing infrastructure. They moved around the roadblocks. Its
an interesting object lesson to see what has happened to those roadblocks.
History may not necessarily precisely repeat itself, but it sure does
rhyme a bit.
--
Joseph Landman, Ph.D
Founder and CEO
Scalable Informatics, Inc.
email: land...@scalableinformatics.com
web : http://scalableinformatics.com
twtr : @scalableinfo
phone: +1 734 786 8423 x121
cell : +1 734 612 4615
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