Does Pgbouncer answer to kill command?
There is a difference here. The killall -INT sends INT signal while kill sends TERM signal if no signal is specified. You can try again with kill -INT 1 to see whether it gets the same behavior. I think the pgbouncer process is also catching INT.
Here is reference to the site:
int cf_shutdown; /* 1 - wait for queries to finish, 2 - shutdown immediately */...static void handle_sigterm(evutil_socket_t sock, short flags, void *arg){ log_info("got SIGTERM, fast exit"); /* pidfile cleanup happens via atexit() */ exit(1);} static void handle_sigint(evutil_socket_t sock, short flags, void *arg){ log_info("got SIGINT, shutting down"); sd_notify(0, "STOPPING=1"); if (cf_reboot) die("takeover was in progress, going down immediately"); if (cf_pause_mode == P_SUSPEND) die("suspend was in progress, going down immediately"); cf_pause_mode = P_PAUSE; cf_shutdown = 1;}Pgbouncer stops processing any more queries when the INT signal is given while the TERM signal will terminate the process immediately.