Easy EC2 configuration question

Hello List.
I am obviously doing something very wrong, but after two days of poking at the configuration, I thought it might be more efficacious to ask the list.
I currently have two amazon EC2 instances dedicated to ES, both running Ubuntu 10.10.

I have this minimal configuration in elasticsearch.yml -


the machines are named esearch_1 and esearch_2 (I mention just in passing)

Here is what I see when I run ES on each machine. Notice that neither machine sees the other:

root@esearch_1:~$/mnt/flow/elasticsearch-0.14.4/bin/elasticsearch -f
[2011-02-14 19:50:20,347][INFO ][node ] [Hephaestus] {elasticsearch/0.14.4}[3161]: initializing ...
[2011-02-14 19:50:20,442][INFO ][plugins ] [Hephaestus] loaded []
[2011-02-14 19:50:23,995][INFO ][node ] [Hephaestus] {elasticsearch/0.14.4}[3161]: initialized
[2011-02-14 19:50:23,995][INFO ][node ] [Hephaestus] {elasticsearch/0.14.4}[3161]: starting ...
[2011-02-14 19:50:24,181][INFO ][transport ] [Hephaestus] bound_address {inet[/0:0:0:0:0:0:0:0:9300]}, publish_address {inet[/]}
[2011-02-14 19:50:27,285][INFO ][cluster.service ] [Hephaestus] new_master [Hephaestus][E4425jmERGy-JJAfUoi-GA][inet[/]], reason: zen-disco-join (elected_as_master)
[2011-02-14 19:50:27,417][INFO ][discovery ] [Hephaestus] elasticsearch/E4425jmERGy-JJAfUoi-GA
[2011-02-14 19:50:27,434][INFO ][http ] [Hephaestus] bound_address {inet[/0:0:0:0:0:0:0:0:9200]}, publish_address {inet[/]}
[2011-02-14 19:50:27,435][INFO ][node ] [Hephaestus] {elasticsearch/0.14.4}[3161]: started

root@esearch_2:~$/mnt/flow/elasticsearch-0.14.4/bin/elasticsearch -f
[2011-02-14 19:49:11,978][INFO ][node ] [Aero] {elasticsearch/0.14.4}[18844]: initializing ...
[2011-02-14 19:49:11,981][INFO ][plugins ] [Aero] loaded []
[2011-02-14 19:49:15,777][INFO ][node ] [Aero] {elasticsearch/0.14.4}[18844]: initialized
[2011-02-14 19:49:15,778][INFO ][node ] [Aero] {elasticsearch/0.14.4}[18844]: starting ...
[2011-02-14 19:49:15,935][INFO ][transport ] [Aero] bound_address {inet[/0:0:0:0:0:0:0:0:9300]}, publish_address {inet[/]}
[2011-02-14 19:49:19,137][INFO ][cluster.service ] [Aero] new_master [Aero][ax2BL-VlSkOU31zdlOriKg][inet[/]], reason: zen-disco-join (elected_as_master)
[2011-02-14 19:49:19,244][INFO ][discovery ] [Aero] elasticsearch/ax2BL-VlSkOU31zdlOriKg
[2011-02-14 19:49:19,410][INFO ][http ] [Aero] bound_address {inet[/0:0:0:0:0:0:0:0:9200]}, publish_address {inet[/]}
[2011-02-14 19:49:19,410][INFO ][node ] [Aero] {elasticsearch/0.14.4}[18844]: started

Please notice that both machines decide to be a master:
e.g. - new_master [Hephaestus][E4425jmERGy-JJAfUoi-GA][inet[/]], reason: zen-disco-join (elected_as_master)

Obviously I have mangled the configuration somehow, but after trying several different things, I am at a loss.

Thank you for any configuration help you can provide!
Dave Kirkpatrick