Oliveira, consegui fazer funcionar um esqueminha do XC no AWS... (subi vários nós)....

deploying_xc_aws.log

[ec2-user@ip-10-0-0-74 ~]$ ls -la
total 6992
drwx------ 3 ec2-user ec2-user    4096 Sep 17 06:56 .
drwxr-xr-x 4 root     root        4096 Sep 17 04:24 ..
-rw------- 1 ec2-user ec2-user     261 Sep 17 02:56 .bash_history
-rw-r--r-- 1 ec2-user ec2-user      18 Feb 27  2013 .bash_logout
-rw-r--r-- 1 ec2-user ec2-user     176 Feb 27  2013 .bash_profile
-rw-r--r-- 1 ec2-user ec2-user     124 Feb 27  2013 .bashrc
-rwxrwxr-x 1 ec2-user ec2-user     686 Sep 17 05:20 deploy.sh
-rw-r--r-- 1 ec2-user ec2-user 7107425 Sep 17 05:13 postgresxc-dextra-0.1.tar.gz
-rw------- 1 ec2-user ec2-user    1694 Sep 16 23:22 rsa-aws_postgres.pem
drwx------ 2 ec2-user ec2-user    4096 Sep 16 23:23 .ssh
-rwxrwxr-x 1 ec2-user ec2-user     183 Sep 17 06:56 test.sh
-rw------- 1 ec2-user ec2-user    4611 Sep 17 06:56 .viminfo
[ec2-user@ip-10-0-0-74 ~]$ ./test.sh
                                                           QUERY PLAN
---------------------------------------------------------------------------------------------------------------------------------
 Aggregate  (cost=2.50..2.51 rows=1 width=0) (actual time=0.983..0.984 rows=1 loops=1)
   Output: pg_catalog.count(*)
   ->  Data Node Scan on "__REMOTE_GROUP_QUERY__"  (cost=0.00..0.00 rows=1000 width=0) (actual time=0.926..0.930 rows=2 loops=1)
         Output: (count(*))
         Node/s: dn1, dn2
         Remote query: SELECT count(*) FROM ONLY public.tmodu WHERE true
 Total runtime: 1.139 ms
(7 rows)

[ec2-user@ip-10-0-0-74 ~]$ cat test.sh
#!/bin/bash



/usr/local/postgresxc/bin/psql -h internal-ELB-PGXC-1962958118.us-east-1.elb.amazonaws.com test -U postgres -c "explain (verbose, analyze) select count(*) from tmodu"