Issuing a CTRL-C (SIGINT) on a container running in the foreground doesn't kill it. This makes docker difficult to daemonize with utilities like upstart and supervisord.

# docker run lucid64-base sleep 60
^C
# docker ps
ID             IMAGE                 COMMAND     CREATED         STATUS         COMMENT     PORTS
b062d84ccae1   lucid64-base:latest   sleep 60    4 seconds ago   Up 4 seconds

Discussed with @shykes on IRC:

gabrtv
8:44 shykes: do you see an issue with foreground containers trapping SIGINT/SIGTERM and terminating gracefully? if not, i'd be willing to take a crack at it

shykes
8:44 gabrtv: no design issues per-se, just needs to be implemented
8:45 there are 2 ways: 1) intercept signals in the client, and translate them to 'docker kill' calls (easier) 2) bring back standalone mode (harder)