Why is sssd an unrecognized service, even though it is installed and can be restarted?

Question

Why is sssd an unrecognized service, even though it is installed and can be restarted? BTW: This concerns Ubuntu 14.04.1 LTS, it was not like that in 12.04 I will show what I mean below, I think it is a bug but I am interested in an explanation and/or workaround.

root@tauriel:~/scripts# service sssd
**sssd: unrecognized service**
root@tauriel:~/scripts# service sssd status
sssd start/running, process 22454
root@tauriel:~/scripts# service sssd restart
sssd stop/waiting
sssd start/running, process 22485
root@tauriel:~/scripts# service sssd status
sssd start/running, process 22485
root@tauriel:~/scripts# service sssd
**sssd: unrecognized service**
root@tauriel:~/scripts# 

BTW: sssd is apparently a new tag, it would be nice if it was added.

Answer 1

When you run service, if there's a sysv init script, it will call that script (or call Upstart, if it's an Upstart job):

$ service ssh
 * Usage: /etc/init.d/ssh {start|stop|reload|force-reload|restart|try-restart|status}
$ service gdm
/etc/init.d/gdm: 79: /etc/init.d/gdm: Syntax error: "fi" unexpected (expecting "}")

Naturally if you don't pass a command (restart, status, etc.), only these scripts will be able to respond. If the init file for a service is Upstart-only, this will fail:

$ service tty1
tty1: unrecognized service

SSSD only offers an Upstart init script, as you can see from the list of files in sssd-common.

---

This behaviour is not exactly well documented in the manpage. However, if you examine the service command, which is a shell script:

118 if [ -r "/etc/init/${SERVICE}.conf" ] && which initctl >/dev/null \
119    && initctl version | grep -q upstart
120 then
121    # Upstart configuration exists for this job and we're running on upstart
122    case "${ACTION}" in  

The actions in this case consists of exec calls of initctl (via its symlinked versions - start, stop, etc.). Since the ACTION variable is empty and doesn't match any case, it falls through to:

138 
139 # Otherwise, use the traditional sysvinit
140 if [ -x "${SERVICEDIR}/${SERVICE}" ]; then
141    exec env -i LANG="$LANG" PATH="$PATH" TERM="$TERM" "$SERVICEDIR/$SERVICE" ${ACTION} ${OPTIONS}
142 else
143    echo "${SERVICE}: unrecognized service" >&2
144    exit 1
145 fi

Here you can see why it produces that error.