[PATCH 1/8] docs: daemons: Add section on figuring out whether modular or monolithic daemon is in use

[Erik Skultety]

On Mon, Jan 17, 2022 at 04:39:09PM +0100, Peter Krempa wrote:
> Since we are at a transition period where some users may be running
> monolithic libvirtd and others already the modular topology we need a
> section that allows users to figure out which is in use.
> 
> This will be particularly important in the document about enabling
> logging, as the active log file depends on which daemon is in use.
> 
> Signed-off-by: Peter Krempa <pkrempa at redhat.com>
> ---
>  docs/daemons.rst | 47 +++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 47 insertions(+)
> 
> diff --git a/docs/daemons.rst b/docs/daemons.rst
> index c8ae3b0cef..1446c1f92c 100644
> --- a/docs/daemons.rst
> +++ b/docs/daemons.rst
> @@ -435,6 +435,53 @@ host first.
>        $ systemctl enable virtproxyd-tls.socket
>        $ systemctl start virtproxyd-tls.socket
> 
> +Checking whether modular/monolithic mode is in use
> +==================================================
> +
> +To determine whether modular or monolithic mode is in use on a host running
> +``systemd`` as the init system you can take the following steps:
> +
> +#. Check whether the modular daemon infrastructure is in use
> +
> +   First check whether the modular daemon you are interested in is running:

So, a user is trying to figure out which mode is on (with only a basic knowledge
of libvirt) and they need to pick a daemon of interest. I think we can improve
what you wrote a little by incorporating a more generic bit with the followin:

systemctl list-units -t service -t socket

...
virtnwfilterd.service loaded active running Virtualization nwfilter daemon
virtqemud.service     loaded active running Virtualization qemu daemon
-----------------------------------
...
virtinterfaced-admin.socket  loaded active listening Libvirt interface admin socket
virtinterfaced-ro.socket     loaded active listening Libvirt interface local read-only socket
virtinterfaced.socket        loaded active listening Libvirt interface local socket
virtlockd.socket             loaded active listening Virtual machine lock manager socket
virtlxcd-admin.socket        loaded active listening Libvirt lxc admin socket
virtlxcd-ro.socket           loaded active listening Libvirt lxc local read-only socket
virtlxcd.socket              loaded active listening Libvirt lxc local socket
virtnetworkd-admin.socket    loaded active listening Libvirt network admin socket
virtnetworkd-ro.socket       loaded active listening Libvirt network local read-only socket
virtnetworkd.socket          loaded active listening Libvirt network local socket
virtnodedevd.socket          loaded active listening Libvirt nodedev local socket
virtnwfilterd-admin.socket   loaded active running   Libvirt nwfilter admin socket
virtnwfilterd-ro.socket      loaded active running   Libvirt nwfilter local read-only socket
virtnwfilterd.socket         loaded active running   Libvirt nwfilter local socket
virtproxyd.socket            loaded active listening Libvirt proxy local socket
virtqemud-admin.socket       loaded active running   Libvirt qemu admin socket
virtqemud-ro.socket          loaded active running   Libvirt qemu local read-only socket
virtqemud.socket             loaded active running   Libvirt qemu local socket
virtsecretd.socket           loaded active listening Libvirt secret local socket
virtstoraged.socket          loaded active listening Libvirt storage local socket

If they see a bunch of virt- prefixed sockets/services, then they're running
with in the modular mode.

Otherwise the patch is fine.

Erik

> +
> +   #. Check ``.socket`` for socket activated services
> +
> +     ::
> +
> +       # systemctl is-active virtqemud.socket
> +       active
> +
> +   #. Check ``.service`` for always-running daemons
> +
> +     ::
> +
> +       # systemctl is-active virtqemud.service
> +       active
> +
> +   If either of the above is ``active`` your system is using the modular daemons.
> +
> +#. Check whether the monolithic daemon is in use
> +
> +   #. Check ``libvirtd.socket``
> +
> +     ::
> +
> +       # systemctl is-active libvirtd.socket
> +       active
> +
> +   #. Check ``libvirtd.service`` for always-running daemon
> +
> +     ::
> +
> +       # systemctl is-active libvirtd.service
> +       active
> +
> +   If either of the above is ``active`` your system is using the monolithic
> +   daemon.
> +
> +#. To determine which of the above will be in use on the next boot of the system,
> +   substitute ``is-enabled`` for ``is-active`` in the above examples.
> 
>  Proxy daemon
>  ============
> -- 
> 2.34.1
>