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From William Oberman <ober...@civicscience.com>
Subject Re: advice for EC2 deployment
Date Wed, 27 Apr 2011 13:35:16 GMT
Oh, and Route53 doesn't do anything automatically, but there is an API to
manage the DNS.  It's up to you to run a task on instance boot/terminate, or
a cron job if you want to do this trick (for now, seems like a solid future
feature of Route53).  Though, I hear geographical aware Route53 is already
in the works (to route EC2 traffic to the closest region).

will

On Wed, Apr 27, 2011 at 9:33 AM, William Oberman
<oberman@civicscience.com>wrote:

> I don't think of it as migrating an instance, it's more of a destroy/start
> with EC2.  But, I still think it would be very useful to spin up a set of
> instances with known hostnames (cassandra1, 2, 3... N) and be able to
> quickly SSH to them by doing "ssh
> ec2user@cassandra1.random.ec2.mydomain.com".
>
> Also, it makes finding seeds a lot easier, as you don't have to manage IPs
> in the config file, just names (cassandra-seed1.random.ec2.mydomain.com).
>
> I should have mentioned it, but people that are already doing this trick
> (I'm not... yet) are actually doing: hostname.region.ec2.mydomain.com (as
> it's useful to know the region).  I don't anything cares about AZ, but you
> could embed that too if it matters.
>
> will
>
>
> On Wed, Apr 27, 2011 at 9:26 AM, Sasha Dolgy <sdolgy@gmail.com> wrote:
>
>> if you migrate the instance, does Route53 automatically re-map all the
>> information to the new ec2 instance?  another issue is that cassandra
>> only maintains the IP of the other nodes, and not the hostname
>> (assumed based on output of the nodetool ring)  ...
>>
>> which means, if you migrate the instance and Route53 does do some
>> auto-magic .. the private ip for the instance will have changed and
>> you will need to migrate that node back into the ring, while moving
>> the old referenced IP out ... we've had quite a lot of pain with this
>> in the past.  rule of thumb, if you want to upgrade / migrate an
>> instance, you need to remove it from the ring, do your work, bootstrap
>> it back to the ring .. i think this could be avoided if cassandra
>> maintained hostname references and not just IP references for nodes.
>>
>> -sasha
>>
>> On Wed, Apr 27, 2011 at 2:56 PM, William Oberman
>> <oberman@civicscience.com> wrote:
>> > While I haven't configured it for multi-region yet, Sasha is exactly
>> right
>> > now how amzon's DNS works (returning private vs. public IP depending on
>> if
>> > the machine is local to the region or not).  For extra fun, now that
>> Route53
>> > exists you can (somewhat trivially) map and dynamically maintain all EC2
>> > instances to stable DNS names (but make sure to use CNAMEs to get the
>> DNS
>> > magic!).  E.g.
>> > cassandra1.somethinghardtoguess.ec2.yourdomain.com ->
>> > weird.ec2.public.dns.name
>> >
>> > I'd drop in the somethinghardtoguess myself given Route53 can expose
>> your
>> > internal network topology if someone can guess the DNS name.
>> >
>> > will
>>
>
>
>
> --
> Will Oberman
> Civic Science, Inc.
> 3030 Penn Avenue., First Floor
> Pittsburgh, PA 15201
> (M) 412-480-7835
> (E) oberman@civicscience.com
>



-- 
Will Oberman
Civic Science, Inc.
3030 Penn Avenue., First Floor
Pittsburgh, PA 15201
(M) 412-480-7835
(E) oberman@civicscience.com

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