[libvirt] [PATCH 4/4] rpm: don't enable socket activation in upgrade if --listen present

[Daniel P. Berrangé]

On Mon, Aug 26, 2019 at 04:21:34PM +0200, Ján Tomko wrote:
> On Fri, Aug 23, 2019 at 04:11:43PM +0100, Daniel P. Berrangé wrote:
> > Currently during RPM upgrade we restart libvirtd and unconditionally
> > enable use of systemd socket activation for the UNIX sockets.
> > 
> > If the user had previously given the --listen arg to libvirtd though,
> > this will no longer be honoured if socket activation is used.
> > 
> > We could start libvirtd-tcp.socket or libvirtd-tls.socket for this,
> > but mgmt tools like puppet/ansible might not be expecting this.
> 
> In that case, wouldn't it be better to fail as early as possible? That is,
> leave --listen in the config file and let libvirtd startup fail with
> the error from the previous commit so that people know to fix their
> scripts?

Actively breaking a host during an "yum upgrade" is very undesirable
as that will cause service outage on the existing system.

> Otherwise this might bite them much later in the future when they need
> to e.g. reinstall the VM instead of just upgrading.

Yes, that is true. There is no answer here that is perfect.

When it fails at time of deploying a new host you are less likely to be
causing a production service outage though, as the service does not
yet exist on the host in question.

> > So for now we silently disable socket activation if we see --listen
> > was previously set on the host.
> > 
> > Signed-off-by: Daniel P. Berrangé <berrange at redhat.com>
> > ---
> > libvirt.spec.in | 44 +++++++++++++++++++++++++++++++-------------
> > 1 file changed, 31 insertions(+), 13 deletions(-)
> > 
> 
> But doing this also should make sense to some people.
> Reviewed-by: Ján Tomko <jtomko at redhat.com>

Regards,
Daniel
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