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From William Oberman <ober...@civicscience.com>
Subject Re: advice for EC2 deployment
Date Wed, 27 Apr 2011 13:33:44 GMT
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

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