libvirt/src/virtd.socket.in

[Unit]
Description=libvirt @name@ daemon socket
Conflicts=libvirtd.socket
After=libvirtd.socket

[Socket]
ListenStream=@runstatedir@/libvirt/@sockprefix@-sock
Service=@service@.service
SocketMode=@sockmode@
RemoveOnStop=yes

[Install]
WantedBy=sockets.target
Also=@service@-ro.socket
Also=@service@-admin.socket
systemd: Introduce common templates We already use templating to generate sockets, which are all based off libvirtd's. Push the idea further, and extend it to cover services as well. This is more challenging, as the various modular daemons each have their own needs in terms of what system services needs to be available before they can be started, which other components of libvirt they depend on, and so on. In order to make this sort of per-service tweaks possible, we introduce a Python script that can merge two systemd units together. The script is aware of the semantics of systemd's unit definition format, so it can intelligently merge sections together. This generic systemd unit merging mechanism will also supersede the extremely ad-hoc @deps@ variable, which is currently used in a single scenario. Signed-off-by: Andrea Bolognani <abologna@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> 2023-09-19 17:28:55 +00:00			`[Unit]`
systemd: Improve and unify unit descriptions Hypervisors are referred to by their user-facing name rather than the name of their libvirt driver, the monolithic daemon is explicitly referred to as legacy, and a consistent format is used throughout. Signed-off-by: Andrea Bolognani <abologna@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> 2023-09-25 14:06:09 +00:00			`Description=libvirt @name@ daemon socket`
systemd: Make modular daemons conflict with libvirtd We want to make sure that, at any given time, we have either the modular daemons or the monolithic one running, never both. In order to achieve that, make every single modular unit conflict with the corresponding libvirtd unit. We set both Conflicts=libvirtd.unit and After=libvirtd.unit: this tells systemd that, whenever virtfood.unit and libvirtd.unit are part of the same transaction, the former should win out. Thanks to this, if both the modular daemons and the monolithic one have been enabled because of outdated automation or a simple mistake of the administrator, the request to start libvirtd at boot will be ignored and the result will be a regular modular deployment. If the request to start libvirtd is made when the modular daemons are already running, we have no way to prevent systemd from complying with that request; however, thanks to the way the conflict relationship has been declared, they will be shut down cleanly before libvirtd is started. From the user's point of view, the transition from modular to monolithic will be completely transparent: it's basically the same scenario as a regular package upgrade, just with an extra twist. Note that, while switching from modular to monolithic at runtime happens automatically, going back requires manual intervention, i.e. starting all the necessary sockets one by one. That's okay: the goal here is to prevent misconfiguration and force of habit to accidentally disrupt a working setup, not to encourage the scenario. In a correctly configured and managed host, it should never occur. Signed-off-by: Andrea Bolognani <abologna@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> 2023-09-25 15:24:10 +00:00			`Conflicts=libvirtd.socket`
			`After=libvirtd.socket`
systemd: Introduce common templates We already use templating to generate sockets, which are all based off libvirtd's. Push the idea further, and extend it to cover services as well. This is more challenging, as the various modular daemons each have their own needs in terms of what system services needs to be available before they can be started, which other components of libvirt they depend on, and so on. In order to make this sort of per-service tweaks possible, we introduce a Python script that can merge two systemd units together. The script is aware of the semantics of systemd's unit definition format, so it can intelligently merge sections together. This generic systemd unit merging mechanism will also supersede the extremely ad-hoc @deps@ variable, which is currently used in a single scenario. Signed-off-by: Andrea Bolognani <abologna@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> 2023-09-19 17:28:55 +00:00
			`[Socket]`
			`ListenStream=@runstatedir@/libvirt/@sockprefix@-sock`
			`Service=@service@.service`
			`SocketMode=@sockmode@`
			`RemoveOnStop=yes`

			`[Install]`
			`WantedBy=sockets.target`
systemd: Add Also between sockets This results in all sockets for a service being enabled when a single one of them is. The -tcp and -tls sockets are intentionally excluded, because enabling them should require explicit action on the administrator's part; moreover, disabling them should not result in the local sockets being disabled too. Signed-off-by: Andrea Bolognani <abologna@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> 2023-09-25 15:24:34 +00:00			`Also=@service@-ro.socket`
			`Also=@service@-admin.socket`