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From: Dan Di Spaltro <dan.dispaltro@gmail.com>
Date: Sun, 4 Apr 2010 18:48:27 -0700
Message-ID: <v2wfdec68581004041848qde96ec44x982c150d5b61ea63@mail.gmail.com>
Subject: Re: Deployment on AWS
To: user@cassandra.apache.org
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A little off-topic, but is an availability zone in a separate physical
datacenter?

On Sat, Apr 3, 2010 at 5:08 PM, Benjamin Black <b@b3k.us> wrote:
> Right, you determine AZ by looking at the metadata. =A0us-east-1a is a
> different AZ from us-east-1b. =A0You can't infer anything beyond that,
> either with the AWS API or guesses about IP addressing. =A0My EC2 snitch
> recipe builds a config file for the property snitch that treats AZs
> like racks (just breaking apart the AZ name, nothing magical), and the
> rest is the normal rack aware placement strategy. =A0I am sure folks
> _could_ do interesting things on EC2 with extra code, but I don't see
> extra code as required for these basic features.
>
>
> b
>
> On Sat, Apr 3, 2010 at 3:04 PM, Joe Stump <joe@joestump.net> wrote:
>>
>> On Apr 3, 2010, at 2:54 PM, Benjamin Black wrote:
>>
>>> I'm pretty familiar with EC2, hence the question. =A0I don't believe an=
y
>>> patches are required to do these things. =A0Regardless, as I noted in
>>> that ticket, you definitely do NOT need AWS credentials to determine
>>> your availability zone. =A0It is available through the metadata web
>>> server for each instance as 'placement_availability_zone', avoiding
>>> the need to speak the EC2 API or store credentials in the configs.
>>
>> Good point on the metadata web server. Though I'm unsure how Cassandra w=
ould know anything about those AZ's without using code that's aware of such=
 things, such as the rack-aware strategy we made.
>>
>> Am I missing something further? I asked a friend on the EC2 networking t=
eam if you could determine AZ by IP address and he said, "No."
>>
>> --Joe
>>
>>
>


--=20
Dan Di Spaltro