After a fresh install ("sudo apt-get install postgres-xc postgres-xc-client postgres-xc-doc openssl-blacklist"), it appears that the startup and shutdown sequence of components is out of order in /etc/init.d/postgres-xc.
Correct startup sequence: GTM, Datanode, Coordinator
Correct shutdown sequence: Coordinator, Datanode, GTM
Startup sequence after download: Datanode, Coordinator, GTM
Shutdown sequence after download: GTM, Coordinator, Datanode
Please see:
http://eycheu.blogspot.com/2014/12/postgres-xc-on-lubuntu-1404-lts.html
http://michael.otacoo.com/postgresql-2/start-a-postgres-xc-cluster-in-more-or-less-10-commands/
(I apologize if this was reported before.)
Additional info:
Postgres-XC version: 1.1 (PGXC 1.1, based on PG 9.2.4)
OS info: Ubuntu 14.04.1 LTS