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From "James Moore" <jamesthepi...@gmail.com>
Subject Re: How to manage a large cluster?
Date Thu, 11 Sep 2008 18:01:23 GMT
On Thu, Sep 11, 2008 at 5:46 AM, Allen Wittenauer <aw@yahoo-inc.com> wrote:
> On 9/11/08 2:39 AM, "Alex Loddengaard" <alexlod@google.com> wrote:
>> I've never dealt with a large cluster, though I'd imagine it is managed the
>> same way as small clusters:
>
>    Maybe. :)

Add me to the "maybe :)" column.  In my experience, large rarely turns
out the same as small.

What usually happens is that the developers build the small thing,
keeping in mind that good sysadmins are going to need to do some work
turn it into the large thing.  (Never underestimate the value of good
system admin people.  Speaking as a developer, good sysadmins will
almost always know something about "large" that you haven't thought
about.)

I think what I was doing on a small cluster (100 machines) would take
some modifications to scale up.

>> -Use hostnames or ips, whichever is more convenient for you
>
>    Use hostnames.  Seriously.  Who are you people using raw IPs for things?
> :)  Besides, you're going to need it for the eventual support of Kerberos.

I suspect lots of people buy arrays by the hour from Amazon, so you're
going to have a different batch of IP addresses every
$WHATEVER_PERIOD.  Not having to worry about dynamic dns is probably
interesting to someone.  (Our plan was to spin up an array of 100 or
so servers every N days, work for a few hours, then shut down.)

Dynamic DNS sounded like a pain to me only because I'm a really bad
system administrator - it may be that it's worth it (or trivial).

>    Instead, use a real system configuration management package such as
> bcfg2, smartfrog, puppet, cfengine, etc.  [Steve, you owe me for the plug.
> :) ]

Or on EC2 and its competitors, just build a new image whenever you
need to update Hadoop itself.

-- 
James Moore | james@restphone.com
Ruby and Ruby on Rails consulting
blog.restphone.com

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