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locking: Implement lock failure action in sanlock driver

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While the changes to sanlock driver should be stable, the actual
implementation of sanlock_helper is supposed to be replaced in the
future. However, before we can implement a better sanlock_helper, we
need an administrative interface to libvirtd so that the helper can just
pass a "leases lost" event to the particular libvirt driver and
everything else will be taken care of internally. This approach will
also allow libvirt to pass such event to applications and use
appropriate reasons when changing domain states.

The temporary implementation handles all actions directly by calling
appropriate libvirt APIs (which among other things means that it needs
to know the credentials required to connect to libvirtd).
This commit is contained in:
Jiri Denemark 2012-09-18 13:41:26 +02:00
parent 297c704a1c
commit 893647671b
6 changed files with 277 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
docs/locking.html.in
View File

@ -208,5 +208,29 @@
</pool>
</pre>
<h2><a name="domainconfig">Domain configuration</a></h2>
<p>
In case sanlock loses access to disk locks for some reason, it will
kill all domains that lost their locks. This default behavior may
be changed using
<a href="formatdomain.html#elementsEvents">on_lockfailure
element</a> in domain XML. When this element is present, sanlock
will call <code>sanlock_helper</code> (provided by libvirt) with
the specified action. This helper binary will connect to libvirtd
and thus it may need to authenticate if libvirtd was configured to
require that on the read-write UNIX socket. To provide the
appropriate credentials to sanlock_helper, a
<a href="auth.html#Auth_client_config">client authentication
file</a> needs to contain something like the following:
</p>
<pre>
[auth-libvirt-localhost]
credentials=sanlock
[credentials-sanlock]
authname=login
password=password
</pre>
</body>
</html>

1
libvirt.spec.in
View File

@ -1788,6 +1788,7 @@ rm -f $RPM_BUILD_ROOT%{_sysconfdir}/sysctl.d/libvirtd
%dir %attr(0700, root, root) %{_localstatedir}/lib/libvirt/sanlock
%{_sbindir}/virt-sanlock-cleanup
%{_mandir}/man8/virt-sanlock-cleanup.8*
%attr(0755, root, root) %{_libexecdir}/libvirt_sanlock_helper
%endif
%files client -f %{name}.lang

1
po/POTFILES.in
View File

@ -47,6 +47,7 @@ src/libvirt.c
src/libvirt-qemu.c
src/locking/lock_driver_sanlock.c
src/locking/lock_manager.c
src/locking/sanlock_helper.c
src/lxc/lxc_cgroup.c
src/lxc/lxc_container.c
src/lxc/lxc_conf.c

11
src/Makefile.am
View File

@ -142,6 +142,8 @@ DRIVER_SOURCES = \
LOCK_DRIVER_SANLOCK_SOURCES = \
locking/lock_driver_sanlock.c
LOCK_DRIVER_SANLOCK_HELPER_SOURCES = \
locking/sanlock_helper.c
NETDEV_CONF_SOURCES = \
conf/netdev_bandwidth_conf.h conf/netdev_bandwidth_conf.c \
@ -1649,6 +1651,15 @@ endif
EXTRA_DIST += $(STORAGE_HELPER_DISK_SOURCES)
if HAVE_SANLOCK
libexec_PROGRAMS += libvirt_sanlock_helper
libvirt_sanlock_helper_SOURCES = $(LOCK_DRIVER_SANLOCK_HELPER_SOURCES)
libvirt_sanlock_helper_CFLAGS = -I$(top_srcdir)/src/conf $(AM_CFLAGS)
libvirt_sanlock_helper_LDFLAGS = $(WARN_LDFLAGS) $(AM_LDFLAGS)
libvirt_sanlock_helper_LDADD = libvirt.la
endif
if WITH_LXC
if WITH_LIBVIRTD
libexec_PROGRAMS += libvirt_lxc

115
src/locking/lock_driver_sanlock.c
View File

@ -50,6 +50,7 @@
#define VIR_FROM_THIS VIR_FROM_LOCKING
#define VIR_LOCK_MANAGER_SANLOCK_AUTO_DISK_LOCKSPACE "__LIBVIRT__DISKS__"
#define VIR_LOCK_MANAGER_SANLOCK_KILLPATH LIBEXECDIR "/libvirt_sanlock_helper"
/*
* temporary fix for the case where the sanlock devel package is
@ -75,8 +76,9 @@ struct _virLockManagerSanlockDriver {
static virLockManagerSanlockDriver *driver = NULL;
struct _virLockManagerSanlockPrivate {
const char *vm_uri;
char vm_name[SANLK_NAME_LEN];
char vm_uuid[VIR_UUID_BUFLEN];
unsigned char vm_uuid[VIR_UUID_BUFLEN];
unsigned int vm_id;
unsigned int vm_pid;
unsigned int flags;
@ -383,6 +385,8 @@ static int virLockManagerSanlockNew(virLockManagerPtr lock,
priv->vm_pid = param->value.ui;
} else if (STREQ(param->key, "id")) {
priv->vm_id = param->value.ui;
} else if (STREQ(param->key, "uri")) {
priv->vm_uri = param->value.cstr;
}
}
@ -683,10 +687,86 @@ static int virLockManagerSanlockAddResource(virLockManagerPtr lock,
return 0;
}
static int
virLockManagerSanlockRegisterKillscript(int sock,
const char *vmuri,
const char *uuidstr,
virDomainLockFailureAction action)
{
virBuffer buf = VIR_BUFFER_INITIALIZER;
char *path;
char *args = NULL;
int ret = -1;
int rv;
if (action > VIR_DOMAIN_LOCK_FAILURE_IGNORE) {
virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
_("Failure action %s is not supported by sanlock"),
virDomainLockFailureTypeToString(action));
goto cleanup;
}
virBufferEscape(&buf, '\\', "\\ ", "%s", vmuri);
virBufferAddLit(&buf, " ");
virBufferEscape(&buf, '\\', "\\ ", "%s", uuidstr);
virBufferAddLit(&buf, " ");
virBufferEscape(&buf, '\\', "\\ ", "%s",
virDomainLockFailureTypeToString(action));
if (virBufferError(&buf)) {
virBufferFreeAndReset(&buf);
virReportOOMError();
goto cleanup;
}
/* Unfortunately, sanlock_killpath() does not use const for either
* path or args even though it will just copy them into its own
* buffers.
*/
path = (char *) VIR_LOCK_MANAGER_SANLOCK_KILLPATH;
args = virBufferContentAndReset(&buf);
VIR_DEBUG("Register sanlock killpath: %s %s", path, args);
/* sanlock_killpath() would just crop the strings */
if (strlen(path) >= SANLK_HELPER_PATH_LEN) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Sanlock helper path is longer than %d: '%s'"),
SANLK_HELPER_PATH_LEN - 1, path);
goto cleanup;
}
if (strlen(args) >= SANLK_HELPER_ARGS_LEN) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Sanlock helper arguments are longer than %d:"
" '%s'"),
SANLK_HELPER_ARGS_LEN - 1, args);
goto cleanup;
}
if ((rv = sanlock_killpath(sock, 0, path, args)) < 0) {
if (rv <= -200) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Failed to register lock failure action:"
" error %d"), rv);
} else {
virReportSystemError(-rv, "%s",
_("Failed to register lock failure"
" action"));
}
goto cleanup;
}
ret = 0;
cleanup:
VIR_FREE(args);
return ret;
}
static int virLockManagerSanlockAcquire(virLockManagerPtr lock,
const char *state,
unsigned int flags,
virDomainLockFailureAction action ATTRIBUTE_UNUSED,
virDomainLockFailureAction action,
int *fd)
{
virLockManagerSanlockPrivatePtr priv = lock->privateData;
@ -741,23 +821,32 @@ static int virLockManagerSanlockAcquire(virLockManagerPtr lock,
res_count = priv->res_count;
}
VIR_DEBUG("Register sanlock %d", flags);
/* We only initialize 'sock' if we are in the real
* child process and we need it to be inherited
*
* If sock==-1, then sanlock auto-open/closes a
* temporary sock
*/
if (priv->vm_pid == getpid() &&
(sock = sanlock_register()) < 0) {
if (sock <= -200)
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Failed to open socket to sanlock daemon: error %d"),
sock);
else
virReportSystemError(-sock, "%s",
_("Failed to open socket to sanlock daemon"));
goto error;
if (priv->vm_pid == getpid()) {
VIR_DEBUG("Register sanlock %d", flags);
if ((sock = sanlock_register()) < 0) {
if (sock <= -200)
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Failed to open socket to sanlock daemon: error %d"),
sock);
else
virReportSystemError(-sock, "%s",
_("Failed to open socket to sanlock daemon"));
goto error;
}
if (action != VIR_DOMAIN_LOCK_FAILURE_DEFAULT) {
char uuidstr[VIR_UUID_STRING_BUFLEN];
virUUIDFormat(priv->vm_uuid, uuidstr);
if (virLockManagerSanlockRegisterKillscript(sock, priv->vm_uri,
uuidstr, action) < 0)
goto error;
}
}
if (!(flags & VIR_LOCK_MANAGER_ACQUIRE_REGISTER_ONLY)) {

138
src/locking/sanlock_helper.c Normal file
View File

@ -0,0 +1,138 @@
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <locale.h>
#include "configmake.h"
#include "internal.h"
#include "conf.h"
#include "memory.h"
#include "domain_conf.h"
static int
getArgs(int argc,
char **argv,
const char **uri,
const char **uuid,
virDomainLockFailureAction *action)
{
int act;
if (argc != 4) {
fprintf(stderr, _("%s uri uuid action\n"), argv[0]);
return -1;
}
*uri = argv[1];
*uuid = argv[2];
act = virDomainLockFailureTypeFromString(argv[3]);
if (act < 0) {
fprintf(stderr, _("invalid failure action: '%s'\n"), argv[3]);
return -1;
}
*action = act;
return 0;
}
static int
authCallback(virConnectCredentialPtr cred ATTRIBUTE_UNUSED,
unsigned int ncred ATTRIBUTE_UNUSED,
void *cbdata ATTRIBUTE_UNUSED)
{
return -1;
}
int
main(int argc, char **argv)
{
const char *uri;
const char *uuid;
virDomainLockFailureAction action;
char *xml = NULL;
virConnectPtr conn = NULL;
virDomainPtr dom = NULL;
int ret = EXIT_FAILURE;
int authTypes[] = {
VIR_CRED_AUTHNAME,
VIR_CRED_ECHOPROMPT,
VIR_CRED_PASSPHRASE,
VIR_CRED_NOECHOPROMPT,
};
virConnectAuth auth = {
.credtype = authTypes,
.ncredtype = ARRAY_CARDINALITY(authTypes),
.cb = authCallback,
};
if (setlocale(LC_ALL, "") == NULL ||
bindtextdomain(PACKAGE, LOCALEDIR) == NULL ||
textdomain(PACKAGE) == NULL) {
fprintf(stderr, _("%s: initialization failed\n"), argv[0]);
exit(EXIT_FAILURE);
}
if (getArgs(argc, argv, &uri, &uuid, &action) < 0)
goto cleanup;
if (!(conn = virConnectOpenAuth(uri, &auth, 0)) ||
!(dom = virDomainLookupByUUIDString(conn, uuid)))
goto cleanup;
switch (action) {
case VIR_DOMAIN_LOCK_FAILURE_POWEROFF:
if (virDomainDestroy(dom) == 0 ||
virDomainIsActive(dom) == 0)
ret = EXIT_SUCCESS;
break;
case VIR_DOMAIN_LOCK_FAILURE_RESTART:
if (virDomainIsPersistent(dom)) {
if ((virDomainDestroy(dom) == 0 ||
virDomainIsActive(dom) == 0) &&
virDomainCreate(dom) == 0)
ret = EXIT_SUCCESS;
} else {
xml = virDomainGetXMLDesc(dom,
VIR_DOMAIN_XML_SECURE |
VIR_DOMAIN_XML_INACTIVE);
if (!xml ||
(virDomainDestroy(dom) < 0 &&
virDomainIsActive(dom) != 0))
goto cleanup;
virDomainFree(dom);
if ((dom = virDomainCreateXML(conn, xml, 0)))
ret = EXIT_SUCCESS;
}
break;
case VIR_DOMAIN_LOCK_FAILURE_PAUSE:
if (virDomainSuspend(dom) == 0)
ret = EXIT_SUCCESS;
break;
case VIR_DOMAIN_LOCK_FAILURE_IGNORE:
ret = EXIT_SUCCESS;
break;
default:
fprintf(stderr, _("unsupported failure action: '%s'\n"),
virDomainLockFailureTypeToString(action));
break;
}
cleanup:
if (dom)
virDomainFree(dom);
if (conn)
virConnectClose(conn);
VIR_FREE(xml);
return ret;
}