[systemd-devel] How to exclusively toggle between two systemd instances of a single daemon?

[Zbigniew Jędrzejewski-Szmek]

On Thu, Oct 09, 2014 at 07:51:32AM +0300, Mantas Mikulėnas wrote:
> On Wed, Oct 8, 2014 at 4:39 PM, Zbigniew Jędrzejewski-Szmek <
> zbyszek at in.waw.pl> wrote:
> 
> > On Wed, Oct 08, 2014 at 06:30:51AM -0700, terrygalant.lists at fastest.cc
> > wrote:
> > > Hi
> > >
> > > I have 2 installed instances of a single daemon.
> > >
> > > 1 is from distro-installed packages, installed into standard default OS
> > locations with unit files in /usr/lib/systemd/system/.
> > >
> > > The other is installed under /opt, with unit files currently in
> > /opt/mydaemon/systemd/system/, which can be (un)symlinked as needed into
> > /etc/systemd/system/multi-user.target.wants/ to disable or enable.
> > >
> > > I want to be able to occasionally toggle between use of the 2.
> > >
> > > Is the right systemd way to do manage this toggle to just name the 2
> > instances' unit files differently, put a Conflicts= in each for the other,
> > and just use 'enable' for whichever I want active?
> >
> > That would work.
> >
> > You can also make a symlink from /etc/systemd/system/xxx.service to
> > either of the two files and manage it by hand, calling systemctl
> > daemon-reload afterwards. I think this should work.
> >
> 
> Hmm, isn't this basically the same as adding identical [Install] Alias=
> entries, and using `systemctl enable -f` to manage them?
In some cases yes, but his unit files are outside of the normal search
paths, so I don't this would work.

Zbyszek