qemu: introduce virtqemud daemon

The virtqemud daemon will be responsible for providing the qemu API
driver functionality. The qemu driver is still loaded by the main
libvirtd daemon at this stage, so virtqemud must not be running at
the same time.

Reviewed-by: Andrea Bolognani <abologna@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

.gitignore

@@ -170,6 +170,9 @@
 /src/nwfilter/virtnwfilterd.aug
 /src/nwfilter/virtnwfilterd.conf
 /src/qemu/test_libvirtd_qemu.aug
+/src/qemu/test_virtqemud.aug
+/src/qemu/virtqemud.aug
+/src/qemu/virtqemud.conf
 /src/remote/*_client_bodies.h
 /src/remote/*_protocol.[ch]
 /src/remote/*_stubs.h
@@ -199,6 +202,7 @@
 /src/virtnodedevd
 /src/virtnwfilterd
 /src/virtproxyd
+/src/virtqemud
 /src/virtsecretd
 /src/virtstoraged
 /src/virt-guest-shutdown.target

libvirt.spec.in

@@ -1735,6 +1735,14 @@ exit 0
 
 %if %{with_qemu}
 %files daemon-driver-qemu
+%config(noreplace) %{_sysconfdir}/libvirt/virtqemud.conf
+%{_datadir}/augeas/lenses/virtqemud.aug
+%{_datadir}/augeas/lenses/tests/test_virtqemud.aug
+%{_unitdir}/virtqemud.service
+%{_unitdir}/virtqemud.socket
+%{_unitdir}/virtqemud-ro.socket
+%{_unitdir}/virtqemud-admin.socket
+%attr(0755, root, root) %{_sbindir}/virtqemud
 %dir %attr(0700, root, root) %{_sysconfdir}/libvirt/qemu/
 %dir %attr(0700, root, root) %{_localstatedir}/log/libvirt/qemu/
 %config(noreplace) %{_sysconfdir}/libvirt/qemu.conf

src/qemu/Makefile.inc.am

@@ -112,6 +112,68 @@ CLEANFILES += \
 
 endif WITH_DTRACE_PROBES
 
+sbin_PROGRAMS += virtqemud
+
+nodist_conf_DATA += qemu/virtqemud.conf
+augeas_DATA += qemu/virtqemud.aug
+augeastest_DATA += qemu/test_virtqemud.aug
+CLEANFILES += qemu/virtqemud.aug
+
+virtqemud_SOURCES = $(REMOTE_DAEMON_SOURCES)
+virtqemud_CFLAGS = \
+       $(REMOTE_DAEMON_CFLAGS) \
+       -DDAEMON_NAME="\"virtqemud\"" \
+       -DMODULE_NAME="\"qemu\"" \
+       $(NULL)
+virtqemud_LDFLAGS = $(REMOTE_DAEMON_LD_FLAGS)
+virtqemud_LDADD = $(REMOTE_DAEMON_LD_ADD)
+
+SYSTEMD_UNIT_FILES += \
+	virtqemud.service \
+	virtqemud.socket \
+	virtqemud-ro.socket \
+	virtqemud-admin.socket \
+	$(NULL)
+SYSTEMD_UNIT_FILES_IN += \
+	qemu/virtqemud.service.in \
+	$(NULL)
+
+VIRTQEMUD_UNIT_VARS = \
+	$(VIRTD_UNIT_VARS) \
+	-e 's|[@]name[@]|Libvirt qemu|g' \
+	-e 's|[@]service[@]|virtqemud|g' \
+	-e 's|[@]sockprefix[@]|virtqemud|g' \
+	$(NULL)
+
+virtqemud.service: qemu/virtqemud.service.in $(top_builddir)/config.status
+	$(AM_V_GEN)$(SED) $(VIRTQEMUD_UNIT_VARS) $< > $@-t && mv $@-t $@
+
+virtqemu%.socket: remote/libvirt%.socket.in $(top_builddir)/config.status
+	$(AM_V_GEN)$(SED) $(VIRTQEMUD_UNIT_VARS) $< > $@-t && mv $@-t $@
+
+qemu/virtqemud.conf: remote/libvirtd.conf.in
+	$(AM_V_GEN)$(SED) \
+		-e '/[@]CUT_ENABLE_IP[@]/,/[@]END[@]/d' \
+		-e 's/[@]DAEMON_NAME[@]/virtqemud/' \
+		$< > $@
+
+qemu/virtqemud.aug: remote/libvirtd.aug.in
+	$(AM_V_GEN)$(SED) \
+		-e '/[@]CUT_ENABLE_IP[@]/,/[@]END[@]/d' \
+		-e 's/[@]DAEMON_NAME[@]/virtqemud/' \
+		-e 's/[@]DAEMON_NAME_UC[@]/Virtqemud/' \
+		$< > $@
+
+qemu/test_virtqemud.aug: remote/test_libvirtd.aug.in \
+		qemu/virtqemud.conf $(AUG_GENTEST)
+	$(AM_V_GEN)$(AUG_GENTEST) qemu/virtqemud.conf \
+		$(srcdir)/remote/test_libvirtd.aug.in | \
+		$(SED) \
+		-e '/[@]CUT_ENABLE_IP[@]/,/[@]END[@]/d' \
+		-e 's/[@]DAEMON_NAME[@]/virtqemud/' \
+		-e 's/[@]DAEMON_NAME_UC[@]/Virtqemud/' \
+		> $@ || rm -f $@
+
 conf_DATA += qemu/qemu.conf
 
 augeas_DATA += qemu/libvirtd_qemu.aug

src/qemu/virtqemud.service.in

@@ -0,0 +1,40 @@
+[Unit]
+Description=Virtualization qemu daemon
+Conflicts=libvirtd.service
+Requires=virtqemud.socket
+Requires=virtqemud-ro.socket
+Requires=virtqemud-admin.socket
+Wants=systemd-machined.service
+Before=libvirt-guests.service
+After=network.target
+After=dbus.service
+After=apparmor.service
+After=local-fs.target
+After=remote-fs.target
+After=systemd-logind.service
+After=systemd-machined.service
+Documentation=man:libvirtd(8)
+Documentation=https://libvirt.org
+
+[Service]
+Type=notify
+ExecStart=@sbindir@/virtqemud --timeout 120
+ExecReload=/bin/kill -HUP $MAINPID
+KillMode=process
+Restart=on-failure
+# At least 1 FD per guest, often 2 (eg qemu monitor + qemu agent).
+# eg if we want to support 4096 guests, we'll typically need 8192 FDs
+# If changing this, also consider virtlogd.service & virtlockd.service
+# limits which are also related to number of guests
+LimitNOFILE=8192
+# The cgroups pids controller can limit the number of tasks started by
+# the daemon, which can limit the number of domains for some hypervisors.
+# A conservative default of 8 tasks per guest results in a TasksMax of
+# 32k to support 4096 guests.
+TasksMax=32768
+
+[Install]
+WantedBy=multi-user.target
+Also=virtqemud.socket
+Also=virtqemud-ro.socket
+Also=virtqemud-admin.socket