PostgreSQL systemd config scheme change

[Lennart Poettering]

On Mon, 23.06.14 16:23, Pavel Raiskup (praiskup at redhat.com) wrote:

> Hello all,
> 
> there is currently not so much things to configure in PostgreSQL from
> systemd's service point of view (not taking postgresql.conf into account),
> concretely, we configure PGPORT and PGDATA, from which the later is
> important (and often re-configured to point e.g. to some dedicated mount
> point, etc.).  That tells systemd's unit file where it should start
> PostgreSQL server from.
> 
> What does not seem to be quite 100% OK is that, when user wants to change
> PGDATA, we instruct him to make a separate service file:
> 
>   $ cat /etc/systemd/system/postgresql.service
>   .include /usr/lib/systemd/system/postgresql.service

Please migrate away from ".include", please use .d/ drop-ins instead. We
kinda are deprecating ".include", only support it for compatibility
instead. 

>   [Service]
>   Environment=PGDATA=/some/other/place/than/default
> 
> This works OK -- but the problem is that it is quite too much for just
> changing one simple directory path.
> 
> What seems to be better approach is to have real configuration file, such one
> for which '$ rpm -qc postgresql-server' would not be quiet.  Lets say:
> 
>   $ cat /etc/postgresql/postgresql
>   PGDATA=/some/other/place/than/default
> 
> With some additional packager's work, that allows us to do yet another
> configuration easily - and that is multiple PostgreSQL running on one
> single machine (on different ports or IPs).  The only thing would be to
> create yet another file:
> 
>   $ cat /etc/postgresql/postgresql at com_example
>   PGDATA=/some/path/pg/com_example
>   PGPORT=@SOMEPORT@
>   $ systemctl start postgresql at com_example
> 
> Would you see something bad on that approach (please, take into account that
> we would not stop supporting the old way, we just want to make future
> configuration easier and straight-forward).

Unit files are configuration files. It's OK to copy unit files from
/usr/lib/systemd/system into /etc/systemd/system and edit it there. 

I'd always advise against inventing addition configuration files that
are neither the daemons own, nor systemd's.

Lennart

-- 
Lennart Poettering, Red Hat