[libvirt] [PATCH 00/23] Enable proper use of systemd socket activation with libvirtd

[Martin Kletzander]

On Thu, Jun 27, 2019 at 02:04:44PM +0100, Daniel P. Berrangé wrote:
>On Thu, Jun 27, 2019 at 01:56:45PM +0200, Martin Kletzander wrote:
>> On Thu, Jun 27, 2019 at 10:54:29AM +0100, Daniel P. Berrangé wrote:
>> > The libvirtd daemon has some support for systemd socket activation
>> > from:
>> >
>> >  commit 27a7081c2968ca0d7fbd590629b5a5303851f4a3
>> >  Author: Martin Kletzander <mkletzan at redhat.com>
>> >  Date:   Tue Jul 15 15:28:53 2014 +0200
>> >
>> >    daemon: support passing FDs from the calling process
>> >
>> >    First FD is the RW unix socket to listen on, second one (if
>> >    applicable) is the RO unix socket.
>> >
>> > This was originally intended for use by the libvirt client when doing
>> > auto-spawning of libvirtd, but we later deleted that client side code
>> > in
>> >
>> >  commit be78814ae07f092d9c4e71fd82dd1947aba2f029
>> >  Author: Michal Privoznik <mprivozn at redhat.com>
>> >  Date:   Thu Apr 2 14:41:17 2015 +0200
>> >
>> >    virNetSocketNewConnectUNIX: Use flocks when spawning a daemon
>> >
>> > We never added systemd socket units before as we need libvirtd to start
>> > on boot to perform autostart.
>> >
>> > It was recently pointed out by Lennart that these two features are not
>> > mutually exclusive though. Libvirtd can be set to start on boot, and
>> > also have socket unit files.
>> >
>> > The idea is that we start libvirtd on boot, perform autostart, and then
>> > libvirtd can exit if nothing is running. The socket unit files are then
>> > there to start it again when a mgmt app connects.
>> >
>>
>> How do you deal with responding to QEMU events, for example proper support for
>> <on_poweroff>restart</on_poweroff> ?
>
>If any QEMU guest is running, libvirtd will keep running. The --timeout
>option should only let us exit if we have no client apps and no running
>QEMUs, unless I'm mis-remembering.
>

As far as I remember the session daemon was basing this on connected clients,
but it might've changed since.  I just wanted to point out this might be
something to keep in mind as the reason for not having this setup was something
along the lines of this issue.

>
>Regards,
>Daniel
>-- 
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