提交 d6006672 编写于 作者: D Daniel P. Berrangé

qemu: introduce a new "virt-qemu-run" program

The previous "QEMU shim" proof of concept was taking an approach of only
caring about initial spawning of the QEMU process. It was then
registered with the libvirtd daemon who took over management of it. The
intent was that later libvirtd would be refactored so that the shim
retained control over the QEMU monitor and libvirt just forwarded APIs
to each shim as needed. This forwarding of APIs would require quite alot
of significant refactoring of libvirtd to achieve.

This impl thus takes a quite different approach, explicitly deciding to
keep the VMs completely separate from those seen & managed by libvirtd.
Instead it uses the new "qemu:///embed" URI scheme to embed the entire
QEMU driver in the shim, running with a custom root directory.

Once the driver is initialization, the shim starts a VM and then waits
to shutdown automatically when QEMU shuts down, or should kill QEMU if
it is terminated itself. This ought to use the AUTO_DESTROY feature but
that is not yet available in embedded mode, so we rely on installing a
few signal handlers to gracefully kill QEMU. This isn't reliable if
we crash of course, but you can restart with the same root dir.

Note this program does not expose any way to manage the QEMU process,
since there's no RPC interface enabled. It merely starts the VM and
cleans up when the guest shuts down at the end. This program is
installed to /usr/bin/virt-qemu-run enabling direct use by end users.
Most use cases will probably want to integrate the concept directly
into their respective application codebases. This standalone binary
serves as a nice demo though, and also provides a way to measure
performance of the startup process quite simply.
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>
上级 3e9076e7
......@@ -2311,7 +2311,7 @@ exclude_file_name_regexp--sc_prohibit_devname = \
^(tools/virsh.pod|build-aux/syntax-check\.mk|docs/.*)$$
exclude_file_name_regexp--sc_prohibit_virXXXFree = \
^(docs/|tests/|examples/|tools/|build-aux/syntax-check\.mk|src/test/test_driver.c|src/libvirt_public.syms|include/libvirt/libvirt-(domain|network|nodedev|storage|stream|secret|nwfilter|interface|domain-snapshot).h|src/libvirt-(domain|qemu|network|nodedev|storage|stream|secret|nwfilter|interface|domain-snapshot).c$$)
^(docs/|tests/|examples/|tools/|build-aux/syntax-check\.mk|src/test/test_driver.c|src/libvirt_public.syms|include/libvirt/libvirt-(domain|network|nodedev|storage|stream|secret|nwfilter|interface|domain-snapshot).h|src/libvirt-(domain|qemu|network|nodedev|storage|stream|secret|nwfilter|interface|domain-snapshot).c|src/qemu/qemu_shim.c$$)
exclude_file_name_regexp--sc_prohibit_sysconf_pagesize = \
^(build-aux/syntax-check\.mk|src/util/vir(hostmem|util)\.c)$$
......
......@@ -248,6 +248,11 @@ if WITH_SANLOCK
else ! WITH_SANLOCK
manpages_rst += manpages/virt-sanlock-cleanup.rst
endif ! WITH_SANLOCK
if WITH_QEMU
manpages1_rst += manpages/virt-qemu-run.rst
else ! WITH_QEMU
manpages_rst += manpages/virt-qemu-run.rst
endif ! WITH_QEMU
manpages_rst_html_in = \
$(manpages_rst:%.rst=%.html.in)
manpages_html = \
......
......@@ -19,6 +19,7 @@ Tools
* `virt-login-shell(1) <virt-login-shell.html>`__ - tool to execute a shell within a container
* `virt-admin(1) <virt-admin.html>`__ - daemon administration interface
* `virsh(1) <virsh.html>`__ - management user interface
* `virt-qemu-run(1) <virt-qemu-run.html)`__ - run standalone QEMU instances
Key codes
=========
......
=============
virt-qemu-run
=============
---------------------------
Run a standalone QEMU guest
---------------------------
:Manual section: 1
:Manual group: Virtualization Support
.. contents::
SYNOPSIS
========
``virt-qemu-run [OPTIONS...] [IGUEST-XML]
DESCRIPTION
===========
This tool provides a way to run a standalone QEMU guest such that it
is completely independant of libvirtd. It makes use of the embedded
QEMU driver support to run the VM placing files under an isolated
directory tree. When the guest is run with this tool it is invisible
to libvirtd and thus also invisible to other libvirt tools such as
virsh.
The virt-qemu-run program will run the QEMU virtual machine, and then
block until the guest OS shuts down, at which point it will exit.
If the virt-qemu-run program is interrupted (eg Ctrl-C) it will
immediately terminate the virtual machine without giving the guest
OS any opportunity to gracefully shutdown.
OPTIONS
=======
``GUEST-XML``
The full path to the XML file describing the guest virtual machine
to be booted.
``-h``, ``--help``
Display the command line help
``-v``, ``--verbose``
Display verbose information about startup
``-r DIR``, ``--root=DIR``
Specify the root directory to use for storing state associated with
the virtual machine. The caller is responsible for deleting this
directory when it is no longer required.
If this parameter is omitted, then a random temporary directory
will be created, and its contents be automaticlaly deleted at
VM shutdown.
``-s XML-FILE,VALUE-FILE``, ``--secret=XML-FILE,VALUE-FILE``
Specify a secret to be loaded into the secret driver. The ``XML-FILE``
is a path to the XML description of the secret, whose UUID should
match a secret referenced in the guest domain XML. The ``VALUE-FILE``
is a path containing the raw value of the secret.
EXIT STATUS
===========
Upon successful shutdown, an exit status of 0 will be set. Upon
failure a non-zero status will be set.
AUTHOR
======
Daniel P. Berrangé
BUGS
====
Please report all bugs you discover. This should be done via either:
#. the mailing list
`https://libvirt.org/contact.html <https://libvirt.org/contact.html>`_
#. the bug tracker
`https://libvirt.org/bugs.html <https://libvirt.org/bugs.html>`_
Alternatively, you may report bugs to your software distributor / vendor.
COPYRIGHT
=========
Copyright (C) 2019 by Red Hat, Inc.
LICENSE
=======
``virt-run-qemu`` is distributed under the terms of the GNU LGPL v2+.
This is free software; see the source for copying conditions. There
is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE
SEE ALSO
========
virsh(1), `https://libvirt.org/ <https://libvirt.org/>`_
......@@ -1749,6 +1749,8 @@ exit 0
%{_libdir}/%{name}/connection-driver/libvirt_driver_qemu.so
%dir %attr(0711, root, root) %{_localstatedir}/lib/libvirt/swtpm/
%dir %attr(0711, root, root) %{_localstatedir}/log/swtpm/libvirt/qemu/
%{_bindir}/virt-qemu-run
%{_mandir}/man1/virt-qemu-run.1*
%endif
%if %{with_lxc}
......
......@@ -87,6 +87,7 @@ OPENRC_INIT_FILES_IN =
OPENRC_CONF_FILES =
SYSCONF_FILES =
sbin_PROGRAMS =
bin_PROGRAMS =
DRIVER_SOURCES =
COMMON_UNIT_VARS = \
......
......@@ -243,3 +243,16 @@ EXTRA_DIST += \
qemu/THREADS.txt \
libvirt_qemu_probes.d \
$(NULL)
QEMU_SHIM_SOURCES = qemu/qemu_shim.c
EXTRA_DIST += $(QEMU_SHIM_SOURCES)
if WITH_QEMU
bin_PROGRAMS += virt-qemu-run
virt_qemu_run_SOURCES = $(QEMU_SHIM_SOURCES)
virt_qemu_run_LDADD = libvirt.la
virt_qemu_run_LDFLAGS = -Wl,--export-dynamic
endif WITH_QEMU
/*
* qemu_shim.c: standalone binary for running QEMU instances
*
* Copyright (C) 2019 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* <http://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <stdio.h>
#include <stdbool.h>
#include "virfile.h"
#include "virstring.h"
#include "virgettext.h"
#define VIR_FROM_THIS VIR_FROM_QEMU
static bool eventQuitFlag;
static int eventQuitFD = -1;
static virDomainPtr dom;
static void *
qemuShimEventLoop(void *opaque G_GNUC_UNUSED)
{
while (!eventQuitFlag)
virEventRunDefaultImpl();
return NULL;
}
/* Runs in event loop thread context */
static void
qemuShimEventLoopStop(int watch G_GNUC_UNUSED,
int fd G_GNUC_UNUSED,
int event G_GNUC_UNUSED,
void *opaque G_GNUC_UNUSED)
{
char c;
ignore_value(read(fd, &c, 1));
eventQuitFlag = true;
}
/* Runs in event loop thread context */
static int
qemuShimDomShutdown(virConnectPtr econn G_GNUC_UNUSED,
virDomainPtr edom G_GNUC_UNUSED,
int event,
int detail G_GNUC_UNUSED,
void *opaque G_GNUC_UNUSED)
{
if (event == VIR_DOMAIN_EVENT_STOPPED)
eventQuitFlag = true;
return 0;
}
/* Runs in unknown thread context */
static void
qemuShimSigShutdown(int sig G_GNUC_UNUSED)
{
if (dom)
virDomainDestroy(dom);
ignore_value(safewrite(eventQuitFD, "c", 1));
}
static void
qemuShimQuench(void *userData G_GNUC_UNUSED,
virErrorPtr error G_GNUC_UNUSED)
{
}
int main(int argc, char **argv)
{
GThread *eventLoopThread = NULL;
virConnectPtr conn = NULL;
virConnectPtr sconn = NULL;
g_autofree char *xml = NULL;
g_autofree char *uri = NULL;
g_autofree char *suri = NULL;
char *root = NULL;
bool tmproot = false;
int ret = 1;
g_autoptr(GError) error = NULL;
g_auto(GStrv) secrets = NULL;
gboolean verbose = false;
gboolean debug = false;
GStrv tmpsecrets;
GOptionContext *ctx;
GOptionEntry entries[] = {
{ "secret", 's', 0, G_OPTION_ARG_STRING_ARRAY, &secrets, "Load secret file", "SECRET-XML-FILE,SECRET-VALUE-FILE" },
{ "root", 'r', 0, G_OPTION_ARG_STRING, &root, "Root directory", "DIR"},
{ "debug", 'd', 0, G_OPTION_ARG_NONE, &debug, "Debug output", NULL },
{ "verbose", 'v', 0, G_OPTION_ARG_NONE, &verbose, "Verbose output", NULL },
{ 0 }
};
int quitfd[2] = {-1, -1};
long long start = g_get_monotonic_time();
#define deltams() ((long long)g_get_monotonic_time() - start)
ctx = g_option_context_new("- run a standalone QEMU process");
g_option_context_add_main_entries(ctx, entries, PACKAGE);
if (!g_option_context_parse(ctx, &argc, &argv, &error)) {
g_printerr("%s: option parsing failed: %s\n",
argv[0], error->message);
return 1;
}
if (argc != 2) {
g_autofree char *help = g_option_context_get_help(ctx, TRUE, NULL);
g_printerr("%s", help);
return 1;
}
if (verbose)
g_printerr("%s: %lld: initializing libvirt\n",
argv[0], deltams());
if (virInitialize() < 0) {
g_printerr("%s: cannot initialize libvirt\n", argv[0]);
return 1;
}
if (virGettextInitialize() < 0) {
g_printerr("%s: cannot initialize libvirt translations\n", argv[0]);
return 1;
}
virSetErrorFunc(NULL, qemuShimQuench);
if (verbose)
g_printerr("%s: %lld: initializing signal handlers\n",
argv[0], deltams());
signal(SIGTERM, qemuShimSigShutdown);
signal(SIGINT, qemuShimSigShutdown);
signal(SIGQUIT, qemuShimSigShutdown);
signal(SIGHUP, qemuShimSigShutdown);
if (root == NULL) {
if (!(root = g_dir_make_tmp("libvirt-qemu-shim-XXXXXX", &error))) {
g_printerr("%s: cannot create temporary dir: %s\n",
argv[0], error->message);
return 1;
}
tmproot = true;
}
virFileActivateDirOverrideForProg(argv[0]);
if (verbose)
g_printerr("%s: %lld: preparing event loop thread\n",
argv[0], deltams());
virEventRegisterDefaultImpl();
if (pipe(quitfd) < 0) {
g_printerr("%s: cannot create event loop pipe: %s",
argv[0], g_strerror(errno));
goto cleanup;
}
if (virEventAddHandle(quitfd[0], VIR_EVENT_HANDLE_READABLE, qemuShimEventLoopStop, NULL, NULL) < 0) {
VIR_FORCE_CLOSE(quitfd[0]);
VIR_FORCE_CLOSE(quitfd[1]);
quitfd[0] = quitfd[1] = -1;
g_printerr("%s: cannot register event loop handle: %s",
argv[0], virGetLastErrorMessage());
goto cleanup;
}
eventQuitFD = quitfd[1];
eventLoopThread = g_thread_new("event-loop", qemuShimEventLoop, NULL);
if (secrets && *secrets) {
suri = g_strdup_printf("secret:///embed?root=%s", root);
if (verbose)
g_printerr("%s: %lld: opening %s\n",
argv[0], deltams(), suri);
sconn = virConnectOpen(suri);
if (!sconn) {
g_printerr("%s: cannot open %s: %s\n",
argv[0], suri, virGetLastErrorMessage());
goto cleanup;
}
tmpsecrets = secrets;
while (tmpsecrets && *tmpsecrets) {
g_auto(GStrv) bits = g_strsplit(*tmpsecrets, ",", 2);
g_autofree char *sxml = NULL;
g_autofree char *value = NULL;
virSecretPtr sec;
size_t nvalue;
if (!bits || bits[0] == NULL || bits[1] == NULL) {
g_printerr("%s: expected a pair of filenames for --secret argument\n",
argv[0]);
goto cleanup;
}
if (verbose)
g_printerr("%s: %lld: loading secret %s and %s\n",
argv[0], deltams(), bits[0], bits[1]);
if (!g_file_get_contents(bits[0], &sxml, NULL, &error)) {
g_printerr("%s: cannot read secret XML %s: %s\n",
argv[0], bits[0], error->message);
goto cleanup;
}
if (!g_file_get_contents(bits[1], &value, &nvalue, &error)) {
g_printerr("%s: cannot read secret value %s: %s\n",
argv[0], bits[1], error->message);
goto cleanup;
}
if (!(sec = virSecretDefineXML(sconn, sxml, 0))) {
g_printerr("%s: cannot define secret %s: %s\n",
argv[0], bits[0], virGetLastErrorMessage());
goto cleanup;
}
if (virSecretSetValue(sec, (unsigned char *)value, nvalue, 0) < 0) {
virSecretFree(sec);
g_printerr("%s: cannot set value for secret %s: %s\n",
argv[0], bits[0], virGetLastErrorMessage());
goto cleanup;
}
virSecretFree(sec);
tmpsecrets++;
}
}
uri = g_strdup_printf("qemu:///embed?root=%s", root);
if (verbose)
g_printerr("%s: %lld: opening %s\n",
argv[0], deltams(), uri);
conn = virConnectOpen(uri);
if (!conn) {
g_printerr("%s: cannot open %s: %s\n",
argv[0], uri, virGetLastErrorMessage());
goto cleanup;
}
if (virConnectDomainEventRegisterAny(
conn, dom, VIR_DOMAIN_EVENT_ID_LIFECYCLE,
VIR_DOMAIN_EVENT_CALLBACK(qemuShimDomShutdown),
NULL, NULL) < 0) {
g_printerr("%s: cannot regiser for lifecycle events: %s\n",
argv[0], virGetLastErrorMessage());
goto cleanup;
}
if (verbose)
g_printerr("%s: %lld: starting guest %s\n",
argv[0], deltams(), argv[1]);
if (!g_file_get_contents(argv[1], &xml, NULL, &error)) {
g_printerr("%s: cannot read %s: %s\n",
argv[0], argv[1], error->message);
goto cleanup;
}
dom = virDomainCreateXML(conn, xml, 0);
if (!dom) {
g_printerr("%s: cannot start VM: %s\n",
argv[0], virGetLastErrorMessage());
goto cleanup;
}
if (verbose)
g_printerr("%s: %lld: guest running, Ctrl-C to stop nowbbbb\n",
argv[0], deltams());
if (debug) {
g_autofree char *newxml = NULL;
newxml = virDomainGetXMLDesc(dom, 0);
g_printerr("%s: XML: %s\n", argv[0], newxml);
}
ret = 0;
cleanup:
if (ret != 0 && eventQuitFD != -1)
ignore_value(safewrite(eventQuitFD, "c", 1));
if (eventLoopThread != NULL && (ret == 0 || eventQuitFD != -1))
g_thread_join(eventLoopThread);
VIR_FORCE_CLOSE(quitfd[0]);
VIR_FORCE_CLOSE(quitfd[1]);
if (dom != NULL)
virDomainFree(dom);
if (sconn != NULL)
virConnectClose(sconn);
if (conn != NULL)
virConnectClose(conn);
if (tmproot)
virFileDeleteTree(root);
if (verbose)
g_printerr("%s: %lld: cleaned up, exiting\n",
argv[0], deltams());
return ret;
}
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