External/libvirt
1
0
Fork 0
mirror of https://gitlab.com/libvirt/libvirt.git synced 2025-01-21 20:15:17 +00:00
Code Issues Packages Projects Releases Wiki Activity

libxl: add hooks support

Browse Source 
Introduce libxl hook and use it for start, prepare, started,
stop, stopped, migrate events.
This commit is contained in:
Cédric Bosdonnat 2016-07-11 13:55:53 +02:00
parent a9aafc0aa0
commit 7d3b2eb58f
6 changed files with 232 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

53
docs/hooks.html.in
View File

@ -17,8 +17,10 @@
(<span class="since">since 0.8.0</span>)<br/><br/></li>
<li>A QEMU guest is started or stopped
(<span class="since">since 0.8.0</span>)<br/><br/></li>
<li>An LXC guest is started or stopped
<li>An LXC guest is started or stopped
(<span class="since">since 0.8.0</span>)<br/><br/></li>
<li>A libxl-handled Xen guest is started or stopped
(<span class="since">since 2.1.0</span>)<br/><br/></li>
<li>A network is started or stopped or an interface is
plugged/unplugged to/from the network
(<span class="since">since 1.2.2</span>)<br/><br/></li>
@ -41,7 +43,7 @@
<br/>
<h2><a name="names">Script names</a></h2>
<p>At present, there are three hook scripts that can be called:</p>
<p>At present, there are five hook scripts that can be called:</p>
<ul>
<li><code>/etc/libvirt/hooks/daemon</code><br/><br/>
Executed when the libvirt daemon is started, stopped, or reloads
@ -50,6 +52,9 @@
Executed when a QEMU guest is started, stopped, or migrated<br/><br/></li>
<li><code>/etc/libvirt/hooks/lxc</code><br /><br/>
Executed when an LXC guest is started or stopped</li>
<li><code>/etc/libvirt/hooks/libxl</code><br/><br/>
Executed when a libxl-handled Xen guest is started, stopped, or
migrated<br/><br/></li>
<li><code>/etc/libvirt/hooks/network</code><br/><br/>
Executed when a network is started or stopped or an
interface is plugged/unplugged to/from the network</li>
@ -235,6 +240,50 @@
</li>
</ul>
<h5><a name="libxl">/etc/libvirt/hooks/libxl</a></h5>
<ul>
<li>Before a Xen guest is started using libxl driver, the libxl hook
script is called in three locations; if any location fails, the guest
is not started. The first location, <span class="since">since
2.1.0</span>, is before libvirt performs any resource
labeling, and the hook can allocate resources not managed by
libvirt. This is called as:<br/>
<pre>/etc/libvirt/hooks/libxl guest_name prepare begin -</pre>
The second location, available <span class="since">Since
2.1.0</span>, occurs after libvirt has finished labeling
all resources, but has not yet started the guest, called as:<br/>
<pre>/etc/libvirt/hooks/libxl guest_name start begin -</pre>
The third location, <span class="since">2.1.0</span>,
occurs after the domain has successfully started up:<br/>
<pre>/etc/libvirt/hooks/libxl guest_name started begin -</pre>
</li>
<li>When a libxl-handled Xen guest is stopped, the libxl hook script
is called in two locations, to match the startup.
First, <span class="since">since 2.1.0</span>, the hook is
called before libvirt restores any labels:<br/>
<pre>/etc/libvirt/hooks/libxl guest_name stopped end -</pre>
Then, after libvirt has released all resources, the hook is
called again, <span class="since">since 2.1.0</span>, to allow
any additional resource cleanup:<br/>
<pre>/etc/libvirt/hooks/libxl guest_name release end -</pre></li>
<li><span class="since">Since 2.1.0</span>, the libxl hook script
is also called at the beginning of incoming migration. It is called
as: <pre>/etc/libvirt/hooks/libxl guest_name migrate begin -</pre>
with domain XML sent to standard input of the script. In this case,
the script acts as a filter and is supposed to modify the domain
XML and print it out on its standard output. Empty output is
identical to copying the input XML without changing it. In case the
script returns failure or the output XML is not valid, incoming
migration will be canceled. This hook may be used, e.g., to change
location of disk images for incoming domains.</li>
<li><span class="since">Since 2.1.0</span>, the libxl hook script
is also called when the libvirtd daemon restarts and reconnects
to previously running Xen domains. If the script fails, the
existing Xen domains will be killed off. It is called as:
<pre>/etc/libvirt/hooks/libxl guest_name reconnect begin -</pre>
</li>
</ul>
<h5><a name="network">/etc/libvirt/hooks/network</a></h5>
<ul>
<li><span class="since">Since 1.2.2</span>, before a network is started,

74
src/libxl/libxl_domain.c
View File

@ -32,6 +32,7 @@
#include "viratomic.h"
#include "virfile.h"
#include "virerror.h"
#include "virhook.h"
#include "virlog.h"
#include "virstring.h"
#include "virtime.h"
@ -737,6 +738,17 @@ libxlDomainCleanup(libxlDriverPrivatePtr driver,
hostdev_flags |= VIR_HOSTDEV_SP_USB;
#endif
/* now that we know it's stopped call the hook if present */
if (virHookPresent(VIR_HOOK_DRIVER_LIBXL)) {
char *xml = virDomainDefFormat(vm->def, cfg->caps, 0);
/* we can't stop the operation even if the script raised an error */
ignore_value(virHookCall(VIR_HOOK_DRIVER_LIBXL, vm->def->name,
VIR_HOOK_LIBXL_OP_STOPPED, VIR_HOOK_SUBOP_END,
NULL, xml, NULL));
VIR_FREE(xml);
}
virHostdevReAttachDomainDevices(hostdev_mgr, LIBXL_DRIVER_NAME,
vm->def, hostdev_flags, NULL);
@ -788,6 +800,17 @@ libxlDomainCleanup(libxlDriverPrivatePtr driver,
VIR_FREE(file);
}
/* The "release" hook cleans up additional resources */
if (virHookPresent(VIR_HOOK_DRIVER_LIBXL)) {
char *xml = virDomainDefFormat(vm->def, cfg->caps, 0);
/* we can't stop the operation even if the script raised an error */
ignore_value(virHookCall(VIR_HOOK_DRIVER_LIBXL, vm->def->name,
VIR_HOOK_LIBXL_OP_RELEASE, VIR_HOOK_SUBOP_END,
NULL, xml, NULL);
VIR_FREE(xml);
}
if (vm->newDef) {
virDomainDefFree(vm->def);
vm->def = vm->newDef;
@ -1107,6 +1130,23 @@ libxlDomainStart(libxlDriverPrivatePtr driver,
if (virDomainObjSetDefTransient(cfg->caps, driver->xmlopt, vm) < 0)
goto cleanup;
/* Run an early hook to set-up missing devices */
if (virHookPresent(VIR_HOOK_DRIVER_LIBXL)) {
char *xml = virDomainDefFormat(vm->def, cfg->caps, 0);
int hookret;
hookret = virHookCall(VIR_HOOK_DRIVER_LIBXL, vm->def->name,
VIR_HOOK_LIBXL_OP_PREPARE, VIR_HOOK_SUBOP_BEGIN,
NULL, xml, NULL);
VIR_FREE(xml);
/*
* If the script raised an error abort the launch
*/
if (hookret < 0)
goto cleanup_dom;
}
if (virDomainLockProcessStart(driver->lockManager,
"xen:///system",
vm,
@ -1135,6 +1175,23 @@ libxlDomainStart(libxlDriverPrivatePtr driver,
vm->def, hostdev_flags) < 0)
goto cleanup_dom;
/* now that we know it is about to start call the hook if present */
if (virHookPresent(VIR_HOOK_DRIVER_LIBXL)) {
char *xml = virDomainDefFormat(vm->def, cfg->caps, 0);
int hookret;
hookret = virHookCall(VIR_HOOK_DRIVER_LIBXL, vm->def->name,
VIR_HOOK_LIBXL_OP_START, VIR_HOOK_SUBOP_BEGIN,
NULL, xml, NULL);
VIR_FREE(xml);
/*
* If the script raised an error abort the launch
*/
if (hookret < 0)
goto cleanup_dom;
}
if (priv->hookRun) {
char uuidstr[VIR_UUID_STRING_BUFLEN];
virUUIDFormat(vm->def->uuid, uuidstr);
@ -1215,6 +1272,23 @@ libxlDomainStart(libxlDriverPrivatePtr driver,
if (virAtomicIntInc(&driver->nactive) == 1 && driver->inhibitCallback)
driver->inhibitCallback(true, driver->inhibitOpaque);
/* finally we can call the 'started' hook script if any */
if (virHookPresent(VIR_HOOK_DRIVER_LIBXL)) {
char *xml = virDomainDefFormat(vm->def, cfg->caps, 0);
int hookret;
hookret = virHookCall(VIR_HOOK_DRIVER_LIBXL, vm->def->name,
VIR_HOOK_LIBXL_OP_STARTED, VIR_HOOK_SUBOP_BEGIN,
NULL, xml, NULL);
VIR_FREE(xml);
/*
* If the script raised an error abort the launch
*/
if (hookret < 0)
goto cleanup_dom;
}
event = virDomainEventLifecycleNewFromObj(vm, VIR_DOMAIN_EVENT_STARTED,
restore_fd < 0 ?
VIR_DOMAIN_EVENT_STARTED_BOOTED :

22
src/libxl/libxl_driver.c
View File

@ -42,6 +42,7 @@
#include "virfile.h"
#include "viralloc.h"
#include "viruuid.h"
#include "virhook.h"
#include "vircommand.h"
#include "libxl_domain.h"
#include "libxl_driver.h"
@ -415,6 +416,27 @@ libxlReconnectDomain(virDomainObjPtr vm,
/* Enable domain death events */
libxl_evenable_domain_death(cfg->ctx, vm->def->id, 0, &priv->deathW);
/* now that we know it's reconnected call the hook if present */
if (virHookPresent(VIR_HOOK_DRIVER_LIBXL) &&
STRNEQ("Domain-0", vm->def->name)) {
char *xml = virDomainDefFormat(vm->def, cfg->caps, 0);
int hookret;
/* we can't stop the operation even if the script raised an error */
hookret = virHookCall(VIR_HOOK_DRIVER_LIBXL, vm->def->name,
VIR_HOOK_LIBXL_OP_RECONNECT, VIR_HOOK_SUBOP_BEGIN,
NULL, xml, NULL);
VIR_FREE(xml);
if (hookret < 0) {
/* Stop the domain if the hook failed */
if (virDomainObjIsActive(vm)) {
libxlDomainDestroyInternal(driver, vm);
virDomainObjSetState(vm, VIR_DOMAIN_SHUTOFF, VIR_DOMAIN_SHUTOFF_FAILED);
}
goto error;
}
}
ret = 0;
cleanup:

57
src/libxl/libxl_migration.c
View File

@ -36,6 +36,7 @@
#include "virstring.h"
#include "virobject.h"
#include "virthread.h"
#include "virhook.h"
#include "rpc/virnetsocket.h"
#include "libxl_domain.h"
#include "libxl_driver.h"
@ -490,9 +491,11 @@ libxlDomainMigrationPrepare(virConnectPtr dconn,
unsigned int flags)
{
libxlDriverPrivatePtr driver = dconn->privateData;
libxlDriverConfigPtr cfg = libxlDriverConfigGet(driver);
libxlMigrationCookiePtr mig = NULL;
virDomainObjPtr vm = NULL;
char *hostname = NULL;
char *xmlout = NULL;
unsigned short port;
char portstr[100];
virURIPtr uri = NULL;
@ -500,6 +503,8 @@ libxlDomainMigrationPrepare(virConnectPtr dconn,
size_t nsocks = 0;
int nsocks_listen = 0;
libxlMigrationDstArgs *args = NULL;
bool taint_hook = false;
libxlDomainObjPrivatePtr priv = NULL;
size_t i;
int ret = -1;
@ -513,6 +518,50 @@ libxlDomainMigrationPrepare(virConnectPtr dconn,
goto error;
}
/* Let migration hook filter domain XML */
if (virHookPresent(VIR_HOOK_DRIVER_LIBXL)) {
char *xml;
int hookret;
if (!(xml = virDomainDefFormat(*def, cfg->caps,
VIR_DOMAIN_XML_SECURE |
VIR_DOMAIN_XML_MIGRATABLE)))
goto error;
hookret = virHookCall(VIR_HOOK_DRIVER_LIBXL, (*def)->name,
VIR_HOOK_LIBXL_OP_MIGRATE, VIR_HOOK_SUBOP_BEGIN,
NULL, xml, &xmlout);
VIR_FREE(xml);
if (hookret < 0) {
goto error;
} else if (hookret == 0) {
if (virStringIsEmpty(xmlout)) {
VIR_DEBUG("Migrate hook filter returned nothing; using the"
" original XML");
} else {
virDomainDefPtr newdef;
VIR_DEBUG("Using hook-filtered domain XML: %s", xmlout);
newdef = virDomainDefParseString(xmlout, cfg->caps, driver->xmlopt,
VIR_DOMAIN_DEF_PARSE_INACTIVE |
VIR_DOMAIN_DEF_PARSE_SKIP_VALIDATE);
if (!newdef)
goto error;
/* TODO At some stage we will want to have some check of what the user
* did in the hook. */
virDomainDefFree(*def);
*def = newdef;
/* We should taint the domain here. However, @vm and therefore
* privateData too are still NULL, so just notice the fact and
* taint it later. */
taint_hook = true;
}
}
}
if (!(vm = virDomainObjListAdd(driver->domains, *def,
driver->xmlopt,
VIR_DOMAIN_OBJ_LIST_ADD_LIVE |
@ -520,6 +569,12 @@ libxlDomainMigrationPrepare(virConnectPtr dconn,
NULL)))
goto error;
*def = NULL;
priv = vm->privateData;
if (taint_hook) {
/* Domain XML has been altered by a hook script. */
priv->hookRun = true;
}
/* Create socket connection to receive migration data */
if (!uri_in) {
@ -640,6 +695,7 @@ libxlDomainMigrationPrepare(virConnectPtr dconn,
}
done:
VIR_FREE(xmlout);
libxlMigrationCookieFree(mig);
if (!uri_in)
VIR_FREE(hostname);
@ -647,6 +703,7 @@ libxlDomainMigrationPrepare(virConnectPtr dconn,
virURIFree(uri);
if (vm)
virObjectUnlock(vm);
virObjectUnref(cfg);
return ret;
}

16
src/util/virhook.c
View File

@ -51,13 +51,15 @@ VIR_ENUM_DECL(virHookSubop)
VIR_ENUM_DECL(virHookQemuOp)
VIR_ENUM_DECL(virHookLxcOp)
VIR_ENUM_DECL(virHookNetworkOp)
VIR_ENUM_DECL(virHookLibxlOp)
VIR_ENUM_IMPL(virHookDriver,
VIR_HOOK_DRIVER_LAST,
"daemon",
"qemu",
"lxc",
"network")
"network",
"libxl")
VIR_ENUM_IMPL(virHookDaemonOp, VIR_HOOK_DAEMON_OP_LAST,
"start",
@ -96,6 +98,15 @@ VIR_ENUM_IMPL(virHookNetworkOp, VIR_HOOK_NETWORK_OP_LAST,
"unplugged",
"updated")
VIR_ENUM_IMPL(virHookLibxlOp, VIR_HOOK_LIBXL_OP_LAST,
"start",
"stopped",
"prepare",
"release",
"migrate",
"started",
"reconnect")
static int virHooksFound = -1;
/**
@ -261,6 +272,9 @@ virHookCall(int driver,
case VIR_HOOK_DRIVER_LXC:
opstr = virHookLxcOpTypeToString(op);
break;
case VIR_HOOK_DRIVER_LIBXL:
opstr = virHookLibxlOpTypeToString(op);
break;
case VIR_HOOK_DRIVER_NETWORK:
opstr = virHookNetworkOpTypeToString(op);
}

13
src/util/virhook.h
View File

@ -31,6 +31,7 @@ typedef enum {
VIR_HOOK_DRIVER_QEMU, /* QEmu domains related events */
VIR_HOOK_DRIVER_LXC, /* LXC domains related events */
VIR_HOOK_DRIVER_NETWORK, /* network related events */
VIR_HOOK_DRIVER_LIBXL, /* Xen libxl domains related events */
VIR_HOOK_DRIVER_LAST,
} virHookDriverType;
@ -87,6 +88,18 @@ typedef enum {
VIR_HOOK_NETWORK_OP_LAST,
} virHookNetworkOpType;
typedef enum {
VIR_HOOK_LIBXL_OP_START, /* domain is about to start */
VIR_HOOK_LIBXL_OP_STOPPED, /* domain has stopped */
VIR_HOOK_LIBXL_OP_PREPARE, /* domain startup initiated */
VIR_HOOK_LIBXL_OP_RELEASE, /* domain destruction is over */
VIR_HOOK_LIBXL_OP_MIGRATE, /* domain is being migrated */
VIR_HOOK_LIBXL_OP_STARTED, /* domain has started */
VIR_HOOK_LIBXL_OP_RECONNECT, /* domain is being reconnected by libvirt */
VIR_HOOK_LIBXL_OP_LAST,
} virHookLibxlOpType;
int virHookInitialize(void);
int virHookPresent(int driver);