[Beowulf] centos5 as cluster os

Joe Landman landman at scalableinformatics.com
Fri Feb 15 07:52:34 PST 2008

Mark Hahn wrote:
>> whats everyones take on centos as a cluster os.
> works fine for me, but I also don't think distros are very important.
> the critical things are:
>     - must have a decent package system.  yum is; I'm not familiar enough
>     with urpmi or apt to know them.  I think both provide appropriate
>     management of dependencies.

Yum is good, so is apt.  I still have a problem with yum wanting to 
install i386 binaries as well as the x86_64 ones.  Haven't learned how 
to stop that yet (probably simple too).

There is much I do not like about rpm.  However it has a few nice 
features.  I can't live without

	rpm -qa
	rpm -ql package
	rpm -qf file

and am going through withdrawl as apt does not seem to provide these (or 
if they do, it isn't at all obvious how/where).

>     - basic organization has to be familiar, at least to your admins.
>     I'm comfortable with the sysvinit approach, and would rather not
>     figure out what ubuntu has done to init.  I suspect that an ubuntu
>     person can use it to pare down unused services as well.

Not trying to convert anyone here.  Still learning the Ubuntu version. 
Oddly enough it looks *saner* (as in better thought out) than sysvinit 
(which I have used since the early 90s with Irix and others).  I 
actually understand it.

> this, of course, assumes that you will want to pare down and keep updated.
> that's not necessarily the only way to run a cluster, though lack of 
> updates
> would be disasterous if you have any way for users to run random stuff.
> (eg at least 2 local root exploits for linux since oct.)

I favor the minimalist approach.  I get chastised for it every now and 
then (is the labor worth the benefit, is the most reasonable question)?

As few things as possible installed.  Keep it simple.  Fewer things 
means less of an attack surface, a smaller management base, and 
hopefully smaller emergent complexity.

That said, tools like Rocks/Perceus/Scyld/... make cluster standup 
*easy* for particular cases (supported hardware, existing VNFS, ...) 
when you want to do something quick.  Rocks does not currently recommend 
you do yum or up2date updates*.  I imagine similar for Scyld.

You can always roll your own cluster ala Mark, RGB, and others.

* I have been bashed/castigated in 2 fora recently for daring to suggest 
that some technology may have alternatives that one might wish to 
consider, or there may be known issues, or whatever.  Shooting the 
messenger.  Not a wise move.  You don't have to believe me, though I do 
recommend that you make a backup of your Rocks system if you do choose 
to run yum.  You can run yum safely on it, though it takes some work. 
And the Rocks folks have recently formed a user group to help make sure 
it is safe going forward (cudos to the Rocks folks for doing this).

Joseph Landman, Ph.D
Founder and CEO
Scalable Informatics LLC,
email: landman at scalableinformatics.com
web  : http://www.scalableinformatics.com
phone: +1 734 786 8423
fax  : +1 866 888 3112
cell : +1 734 612 4615

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