"So, my question is: If we use the EC2 Snitch patch to set up across regions, will the instance's private IP/interface *ever* be used? Or will all traffic always go in and out of the public interface?? Using the public interface is slower and more expensive that the private interface. "
If you use 2452, communication within a region is via private ip and communication between the regions are public (Handshaking or intial communication will still be via public ip). In EC2 they dont have 2 interface but they nat the public IP.... even then this patch will do the right thing for you. There is comments in the patch.... + * 1) Snitch will automatically set the public IP by querying the AWS API + * + * 2) Snitch will set the private IP as a Gossip application state. + * + * 3) Snitch implements IESCS and will reset the connection if it is within the + * same region to communicate via private IP. + * + * Implements Ec2Snitch to inherit its functionality and extend it for + * Multi-Region. + * + * Operational: All the nodes in this cluster needs to be able to (modify the + * Security group settings in AWS) communicate via Public IP's. Regards, </VJ> On Fri, Jul 29, 2011 at 2:11 PM, Chris Marino <ch...@vsider.com> wrote: > Hello, > > Me and some of my colleagues are about to start some experiments running > Cassandra across EC2 regions using virtual networks and have some questions > about how this is going to work. > > I've read these threads about patching the .yaml file to bind to the Listen > address to the public IP... > > > http://mail-archives.apache.org/mod_mbox/cassandra-user/201104.mbox/%3CBANLkTikWGOtWkBOBAs+ibq5voSmjLm=gQQ@mail.gmail.<http://mail-archives.apache.org/mod_mbox/cassandra-user/201104.mbox/%3CBANLkTikWGOtWkBOBAs+ibq5voSmjLm=g...@mail.gmail.com%3E> > com%3E<http://mail-archives.apache.org/mod_mbox/cassandra-user/201104.mbox/%3CBANLkTikWGOtWkBOBAs+ibq5voSmjLm=g...@mail.gmail.com%3E> > > > http://mail-archives.apache.org/mod_mbox/cassandra-user/201103.mbox/%3CAANLkTikWsuUOjEU228niWi0iDTAO5J=5wO=i=hg33...@mail.gmail.com%3E > > And this EC2 Snitch patch that lets it work across regions... > > https://issues.apache.org/jira/browse/CASSANDRA-2452 > > I'm pretty familiar with EC2 networking, but not very familiar how > Cassandra will use the RPC and Listen ports with this Snitch. > > So, my question is: If we use the EC2 Snitch patch to set up across > regions, will the instance's private IP/interface *ever* be used? Or will > all traffic always go in and out of the public interface?? Using the public > interface is slower and more expensive that the private interface. > > What I'm trying to do is set up a virtual network that lets all the nodes > use private IPs, but can still communicate across regions. > > We're going to try this with a virtual network as well as with the EC2 > Snitch to see how things compare. Being able to use the EC2 private > interface is going to make big difference. > > Thanks in advance. > CM > >
