See http://aws.amazon.com/articles/1145?_encoding=UTF8&jiveRedirect=1#12
The external dns will resolve to the internal IP when resolved internally. Using the internal IP means you are not charged for IO and it makes it clear you do not expect this service to be access from outside. Cheers ----------------- Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 5/09/2012, at 7:37 AM, Yang <teddyyyy...@gmail.com> wrote: > http://www.datastax.com/docs/1.1/initialize/cluster_init > > > says: > > " Note In the - seeds list property, include the internal IP addresses of > each seed node." > > why do I have to use internal IP? > on a EC2 node, > hostname resolution seems to directly give its internal IP: > > $ host aws1devbic1.biqa.ctgrd.com > aws1devbic1.biqa.ctgrd.com is an alias for > ec2-50-17-3-229.compute-1.amazonaws.com. > ec2-50-17-3-229.compute-1.amazonaws.com has address 10.28.166.83 > > so using the public DNS or internal IP seems to be the same thing, or > something I'm missing ? > > Thanks > Yang >
