[systemd-devel] Multiple services using the same core service?

[Lennart Poettering]

On Di, 26.12.17 01:39, 林自均 (johnlinp at gmail.com) wrote:

> Hi folks,
> 
> I am trying to achieve:
> 
>     # systemctl start sshd-shell.service (1)
>     # systemctl start sshd-sftp.service (2)
>     # systemctl stop sshd-shell.service (3)
>     # systemctl stop sshd-sftp.service (4)
> 
> Before the command (1), sshd is not running. By typing (1),
> /etc/sshd_config is configured to accept ssh shell connections but no sftp
> connections, and then start sshd. By typing (2), /etc/sshd_config is
> configured to accept sftp connections too, and sshd is reloaded. By typing
> (3), /etc/sshd_config is configured to refuse ssh shell connection, and
> sshd is reloaded again. By typing (4), sshd will be stopped.

Quite frankly, this is not really in line with how systemd services
are supposed to be used. They are supposed to wrap running processes,
but not wrap configuration applied to others really.

But anyway, of course, it's up to you how to make use of this stuff...

> The current problem is that I don't know if there is a better way to
> achieve this. For example, I have to sleep 1 second before reloading
> sshd-core.service in sshd-shell.service because otherwise sshd didn't setup
> the signal handler for SIGHUP and will terminate itself. Or systemd doesn't
> suggest such use case?

Yes, it's not really in-line with how this stuff was designed...

That said, I am pretty sure there's something wrong with your
sshd-core.service: the unit should not be considered up before the
daemon process is fully running, and that includes having set up
SIGHUP handlers properly.

Most likely the Type= stuff is not set up correctly in that unit (or
sshd is broken and doesn't set things up fully before reporting its
startup being complete).

Lennart

-- 
Lennart Poettering, Red Hat