[ClusterLabs] Q: Is there any plan for pcs to support corosync-notifyd?

[Jehan-Guillaume de Rorthais]

On Thu, 18 Mar 2021 17:29:59 +0900
井上和徳 <kazunori_inoue at newson.co.jp> wrote:

> On Tue, Mar 16, 2021 at 10:23 PM Jehan-Guillaume de Rorthais
> <jgdr at dalibo.com> wrote:
> >  
> > > On Tue, 16 Mar 2021, 09:58 井上和徳, <kazunori_inoue at newson.co.jp> wrote:
> > >  
> > > > Hi!
> > > >
> > > > Cluster (corosync and pacemaker) can be started with pcs,
> > > > but corosync-notifyd needs to be started separately with systemctl,
> > > > which is not easy to use.  
> >
> > Maybe you can add to the [Install] section of corosync-notifyd a dependency
> > with corosync? Eg.:
> >
> >   WantedBy=corosync.service
> >
> > (use systemctl edit corosync-notifyd)
> >
> > Then re-enable the service (without starting it by hands).  
> 
> I appreciate your proposal. How to use WantedBy was helpful!
> However, since I want to start the cluster (corosync, pacemaker) only
> manually, it is unacceptable to start corosync along with corosync-notifyd at
> OS boot time.

This is perfectly fine.

I suppose corosync-notifyd is starting because the default service config has:

  [Install]
  WantedBy=multi-user.target

If you want corosync-notifyd to be enabled ONLY on corosync startup, but noton
system startup, you have to remove this startup dependency on "multi-user"
target. So, your drop-in setup of corosync-notifyd shoudl be (remove leading
spaces):

  cat <<EOF|EDITOR=tee systemctl edit corosync-notifyd.service
  [Install]
  WantedBy=
  WantedBy=corosync.service
  EOF

The first empty WantedBy= removes any pre-existing dependency.

Then disable/enable corosync-notifyd again to install the new dependency and
remove old ones. It should only creates ONE link in
"/etc/systemd/system/corosync.service.wants/corosync-notifyd.service", 
but NOT in "/etc/systemd/system/multi-user.target.wants/".

Regards,