Re: (ITS#8707) slapd: Add systemd service notification support

[ryan@nardis.ca]

On Mon, Aug 07, 2017 at 12:23:27PM -0700, Ryan Tandy wrote:
>I guess MAINPID= is actually needed, unless we run slapd with -d, regardless of
>whether we set Type=forking or Type=notify. Not exactly "needed", but better to
>have it than not.

I experimented a bit with a service file. It seems to work well with 
either Type=forking and NotifyAccess=all, or Type=notify and 
ExecStart=slapd -d none. The latter (disabling forking) is definitely 
what systemd upstream recommends.

In either case, MAINPID= didn't actually seem to help anything.  
NotifyAccess=main has a chicken-and-egg problem, because systemd needs 
to know the main PID in order for us to send it the message containing 
the PID! :) I think the only reasonable way to leave forking enabled 
would be to also require a PIDFile= setting, which solves that problem. 
But I'd rather sidestep the entire thing, omit MAINPID= as well, and 

Looking at the systemctl output I still think STATUS= is redundant and 
could be omitted.

So I guess my recommendation for the notify call boils down to:

rc = sd_notify( 1, "READY=1" );

and a slapd.service along the lines of:

[Unit]
Description=OpenLDAP server

[Service]
Type=notify
ExecStart=%LIBEXECDIR%/slapd -h 'ldap:/// ldapi:///' -d0

[Install]
WantedBy=multi-user.target

(basically identical to the example in systemd.service(5).)

Side note: the version message from slapd appears in the journal twice, 
once with the timestamp and once without... not sure exactly why!