[libvirt] [PATCH] rpm: explicitly enable & start virlockd/virtlogd sockets on install

[Daniel P. Berrange]

On Mon, Dec 07, 2015 at 02:01:11PM +0100, Michal Privoznik wrote:
> On 07.12.2015 13:58, Daniel P. Berrange wrote:
> > On Mon, Dec 07, 2015 at 01:57:20PM +0100, Michal Privoznik wrote:
> >> On 07.12.2015 13:55, Daniel P. Berrange wrote:
> >>> When installing the libvirt-daemon RPM, we have a %post rule to
> >>> enable the libvirtd.service, virtlockd.socket and virtlogd.socket
> >>> files. This is only done, however, when the RPM is first installed,
> >>> not when upgrading RPMs.
> >>>
> >>> This adds a separate rule to explicitly enable the virtlockd.socket
> >>> and virtlogd.socket units upon RPM upgrade, if libvirtd.service
> >>> is marked as enabled.  It also adds a rule to start the socket
> >>> units if libvirtd.service is running.
> >>>
> >>> The downside with taking this approach is that it is impossible
> >>> for a user to have libvirtd.service enabled and disable socket
> >>> activation, because we'll re-enable it on every upgrade. Similarly
> >>> we'll be starting the socket listeners on every upgrade if libvirtd
> >>> is running. This is a pretty nasty thing to have to keep in libvirt
> >>> for the long term, given this upgrade problem is a one-time only
> >>> pain point.
> >>>
> >>> For this reason I am recommending *NOT* applying this patch to GIT.
> >>>
> >>> Instead, I think we just have to release note the fact that after
> >>> upgrading you should enable the virtlockd.socket unit.

> >> ACK
> > 
> > Presumably you didn't read my commit message, or are you ACK'ing my
> > suggestion that we *NOT* merge this ?
> 
> Well, I think that socket activation is nice feature. But as even DV
> pointed out (and I've experienced that too on my non-systemd system)
> that it's impossible to start domains without virtlogd enabled. I find
> it much worse than depending on a 'nice systemd feature'. Therefore I
> think we should merge it.

Hmm, I just noticed that we have used versioned triggers in this scenario
in the past:

eg, when upgrading from a libvirt older than 0.9.4 we have a trigger:

%triggerun client -- libvirt < 0.9.4
%{_bindir}/systemd-sysv-convert --save libvirt-guests >/dev/null 2>&1 ||:

# If the package is allowed to autostart:
/bin/systemctl --no-reload enable libvirt-guests.service >/dev/null 2>&1 ||:

# Run this because the SysV package being removed won't do them
/sbin/chkconfig --del libvirt-guests >/dev/null 2>&1 || :
%endif


So we could probably use

   %triggerun daemon -- libvirt < 1.3.0

to start the virtlogd on upgrade once only, without taking away ability
of admins to permanently disable it later.


Regards,
Daniel
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