[libvirt] Supporting vhost-net and macvtap in libvirt for QEMU
by Anthony Liguori
Disclaimer: I am neither an SR-IOV nor a vhost-net expert, but I've CC'd
people that are who can throw tomatoes at me for getting bits wrong :-)
I wanted to start a discussion about supporting vhost-net in libvirt.
vhost-net has not yet been merged into qemu but I expect it will be soon
so it's a good time to start this discussion.
There are two modes worth supporting for vhost-net in libvirt. The
first mode is where vhost-net backs to a tun/tap device. This is
behaves in very much the same way that -net tap behaves in qemu today.
Basically, the difference is that the virtio backend is in the kernel
instead of in qemu so there should be some performance improvement.
Current, libvirt invokes qemu with -net tap,fd=X where X is an already
open fd to a tun/tap device. I suspect that after we merge vhost-net,
libvirt could support vhost-net in this mode by just doing -net
vhost,fd=X. I think the only real question for libvirt is whether to
provide a user visible switch to use vhost or to just always use vhost
when it's available and it makes sense. Personally, I think the later
makes sense.
The more interesting invocation of vhost-net though is one where the
vhost-net device backs directly to a physical network card. In this
mode, vhost should get considerably better performance than the current
implementation. I don't know the syntax yet, but I think it's
reasonable to assume that it will look something like -net
tap,dev=eth0. The effect will be that eth0 is dedicated to the guest.
On most modern systems, there is a small number of network devices so
this model is not all that useful except when dealing with SR-IOV
adapters. In that case, each physical device can be exposed as many
virtual devices (VFs). There are a few restrictions here though. The
biggest is that currently, you can only change the number of VFs by
reloading a kernel module so it's really a parameter that must be set at
startup time.
I think there are a few ways libvirt could support vhost-net in this
second mode. The simplest would be to introduce a new tag similar to
<source network='br0'>. In fact, if you probed the device type for the
network parameter, you could probably do something like <source
network='eth0'> and have it Just Work.
Another model would be to have libvirt see an SR-IOV adapter as a
network pool whereas it handled all of the VF management. Considering
how inflexible SR-IOV is today, I'm not sure whether this is the best model.
Has anyone put any more thought into this problem or how this should be
modeled in libvirt? Michael, could you share your current thinking for
-net syntax?
--
Regards,
Anthony Liguori
1 year
[libvirt] [PATCH 0/4] Multiple problems with saving to block devices
by Daniel P. Berrange
This patch series makes it possible to save to a block device,
instead of a plain file. There were multiple problems
- WHen save failed, we might de-reference a NULL pointer
- When save failed, we unlinked the device node !!
- The approach of using >> to append, doesn't work with block devices
- CGroups was blocking QEMU access to the block device when enabled
One remaining problem is not in libvirt, but rather QEMU. The QEMU
exec: based migration often fails to detect failure of the command
and will thus hang forever attempting a migration that'll never
succeed! Fortunately you can now work around this in libvirt using
the virsh domjobabort command
11 years, 8 months
[libvirt] [PATCH 0/2] Introduce two new virsh commands
by Osier Yang
These two patches is to introduce two new virsh commands, one is
eject-media, which is to eject media from CD or floppy drive, the other
is insert-media, which is to insert media into CD or floppy drive.
There are commands existed can be used to eject/insert media, such as
"update-device", but it's not quite easy to use. That's the original
intention of these patches.
Both of the two commands only allow to operate on CDROM or floppy disk.
[PATCH 1/2] virsh: Introduce two new commands to insert or eject media
[PATCH 2/2] doc: Add docs for two new introduced commands
Regards
Osier
12 years, 11 months
[libvirt] [PATCH 1/2] Fix order of disks and controllers
by Jiri Denemark
Commit 2d6adabd53c8f1858191d521dc9b4948d1205955 replaced qsorting disk
and controller devices with inserting them at the right position. That
was to fix unnecessary reordering of devices. However, when parsing
domain XML devices are just taken in the order in which they appear in
the XML since. Use the correct insertion algorithm to honor device
target.
---
src/conf/domain_conf.c | 4 +-
.../qemuxml2argvdata/qemuxml2argv-boot-order.args | 35 ++++++++++++-------
tests/qemuxml2argvdata/qemuxml2argv-boot-order.xml | 14 ++++----
tests/xmconfigdata/test-escape-paths.cfg | 2 +-
tests/xmconfigdata/test-escape-paths.xml | 10 +++---
5 files changed, 37 insertions(+), 28 deletions(-)
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index b406202..48ed7eb 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -5883,7 +5883,7 @@ static virDomainDefPtr virDomainDefParseXML(virCapsPtr caps,
if (!disk)
goto error;
- def->disks[def->ndisks++] = disk;
+ virDomainDiskInsertPreAlloced(def, disk);
}
VIR_FREE(nodes);
@@ -5899,7 +5899,7 @@ static virDomainDefPtr virDomainDefParseXML(virCapsPtr caps,
if (!controller)
goto error;
- def->controllers[def->ncontrollers++] = controller;
+ virDomainControllerInsertPreAlloced(def, controller);
}
VIR_FREE(nodes);
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-boot-order.args b/tests/qemuxml2argvdata/qemuxml2argv-boot-order.args
index 23249f3..14367b1 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-boot-order.args
+++ b/tests/qemuxml2argvdata/qemuxml2argv-boot-order.args
@@ -1,13 +1,22 @@
-LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test /usr/bin/qemu -S -M \
-pc -m 214 -smp 1 -nographic -nodefaults -monitor unix:/tmp/test-monitor,server,\
-nowait -no-acpi -drive file=/dev/HostVG/QEMUGuest1,if=none,id=drive-ide0-0-0 \
--device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0 -drive \
-file=sheepdog:example.org:6000:image,if=none,id=drive-virtio-disk0 -device \
-virtio-blk-pci,bus=pci.0,addr=0x4,drive=drive-virtio-disk0,id=virtio-disk0,\
-bootindex=3 -drive file=/root/boot.iso,if=none,media=cdrom,id=drive-ide0-1-0 \
--device ide-drive,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0,\
-bootindex=1 -drive file=/dev/null,if=none,id=drive-fdc0-0-1 -global \
-isa-fdc.driveB=drive-fdc0-0-1 -global isa-fdc.bootindexB=4 -device \
-virtio-net-pci,vlan=0,id=net0,mac=00:11:22:33:44:55,bus=pci.0,addr=0x3,\
-bootindex=2 -net user,vlan=0,name=hostnet0 -usb -device virtio-balloon-pci,\
-id=balloon0,bus=pci.0,addr=0x5
+LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test /usr/bin/qemu \
+-S \
+-M pc \
+-m 214 \
+-smp 1 \
+-nographic \
+-nodefaults \
+-monitor unix:/tmp/test-monitor,server,nowait \
+-no-acpi \
+-drive file=/dev/HostVG/QEMUGuest1,if=none,id=drive-ide0-0-0 \
+-device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0 \
+-drive file=/root/boot.iso,if=none,media=cdrom,id=drive-ide0-1-0 \
+-device ide-drive,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0,bootindex=1 \
+-drive file=sheepdog:example.org:6000:image,if=none,id=drive-virtio-disk0 \
+-device virtio-blk-pci,bus=pci.0,addr=0x4,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=3 \
+-drive file=/dev/null,if=none,id=drive-fdc0-0-1 \
+-global isa-fdc.driveB=drive-fdc0-0-1 \
+-global isa-fdc.bootindexB=4 \
+-device virtio-net-pci,vlan=0,id=net0,mac=00:11:22:33:44:55,bus=pci.0,addr=0x3,bootindex=2 \
+-net user,vlan=0,name=hostnet0 \
+-usb \
+-device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x5
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-boot-order.xml b/tests/qemuxml2argvdata/qemuxml2argv-boot-order.xml
index ba8a9b2..0022c92 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-boot-order.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-boot-order.xml
@@ -18,6 +18,13 @@
<target dev='hda' bus='ide'/>
<address type='drive' controller='0' bus='0' unit='0'/>
</disk>
+ <disk type='file' device='cdrom'>
+ <source file='/root/boot.iso'/>
+ <target dev='hdc' bus='ide'/>
+ <boot order='1'/>
+ <readonly/>
+ <address type='drive' controller='0' bus='1' unit='0'/>
+ </disk>
<disk type='network' device='disk'>
<driver name='qemu' type='raw'/>
<source protocol='sheepdog' name='image'>
@@ -26,13 +33,6 @@
<target dev='vda' bus='virtio'/>
<boot order='3'/>
</disk>
- <disk type='file' device='cdrom'>
- <source file='/root/boot.iso'/>
- <target dev='hdc' bus='ide'/>
- <boot order='1'/>
- <readonly/>
- <address type='drive' controller='0' bus='1' unit='0'/>
- </disk>
<disk type='file' device='floppy'>
<driver name='qemu' type='raw'/>
<source file='/dev/null'/>
diff --git a/tests/xmconfigdata/test-escape-paths.cfg b/tests/xmconfigdata/test-escape-paths.cfg
index e3e6db9..13be2a0 100644
--- a/tests/xmconfigdata/test-escape-paths.cfg
+++ b/tests/xmconfigdata/test-escape-paths.cfg
@@ -19,7 +19,7 @@ vnc = 1
vncunused = 1
vnclisten = "127.0.0.1"
vncpasswd = "123poi"
-disk = [ "phy:/dev/HostVG/XenGuest2,hda,w", "file:/root/boot.iso&test,hdc:cdrom,r", """phy:/dev/HostVG/XenGuest'",hdb,w""" ]
+disk = [ "phy:/dev/HostVG/XenGuest2,hda,w", """phy:/dev/HostVG/XenGuest'",hdb,w""", "file:/root/boot.iso&test,hdc:cdrom,r" ]
vif = [ "mac=00:16:3e:66:92:9c,bridge=xenbr1,script=vif-bridge,model=e1000,type=ioemu" ]
parallel = "none"
serial = "none"
diff --git a/tests/xmconfigdata/test-escape-paths.xml b/tests/xmconfigdata/test-escape-paths.xml
index 13e6e29..9eaf90c 100644
--- a/tests/xmconfigdata/test-escape-paths.xml
+++ b/tests/xmconfigdata/test-escape-paths.xml
@@ -25,17 +25,17 @@
<source dev='/dev/HostVG/XenGuest2'/>
<target dev='hda' bus='ide'/>
</disk>
+ <disk type='block' device='disk'>
+ <driver name='phy'/>
+ <source dev='/dev/HostVG/XenGuest'"'/>
+ <target dev='hdb' bus='ide'/>
+ </disk>
<disk type='file' device='cdrom'>
<driver name='file'/>
<source file='/root/boot.iso&test'/>
<target dev='hdc' bus='ide'/>
<readonly/>
</disk>
- <disk type='block' device='disk'>
- <driver name='phy'/>
- <source dev='/dev/HostVG/XenGuest'"'/>
- <target dev='hdb' bus='ide'/>
- </disk>
<interface type='bridge'>
<mac address='00:16:3e:66:92:9c'/>
<source bridge='xenbr1'/>
--
1.7.5.3
13 years
[libvirt] [PATCH] vbox: Support shared folders
by Matthias Bolte
Shared folders are handled as filesystems and can also be hotplugged.
---
Currently this just maps shared folder to a filesystem element with type
mount. The filesystem element has an accessmode attribute that is not
useful for VirtualBox. Als the target element only has a dir attribute,
but VirtualBox shares doen't support that, you can only give them a name.
<filesystem type='mount' accessmode='passthrough'>
<source dir='/tmp'/>
<target dir='foobar'/>
<readonly/>
</filesystem>
I wonder if we should add a shared folder type like this:
<filesystem type='sharedfolder'>
<source dir='/tmp'/>
<target name='foobar'/>
<readonly/>
</filesystem>
Or is this to specific to VirtualBox?
VirtualBox 4.0 added the automount option that automatically mounts a
shared folder in the guest. On Windows it is mounted to a free drive
letter on Linux it's mounted to /media/<prefix>_<shared-folder-name>.
The <prefix> is a global configuration option in VirtualBox. I wonder
if and how to expose that in libvirt.
Matthias
docs/drvvbox.html.in | 5 ++
src/vbox/vbox_tmpl.c | 140 ++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 145 insertions(+), 0 deletions(-)
diff --git a/docs/drvvbox.html.in b/docs/drvvbox.html.in
index ef55757..1fcafde 100644
--- a/docs/drvvbox.html.in
+++ b/docs/drvvbox.html.in
@@ -61,6 +61,11 @@ vbox+ssh://user@example.com/session (remote access, SSH tunnelled)
<target dev='fda'/>
</disk>
+ <filesystem type='mount'>
+ <source dir='/home/user/stuff'/>
+ <target dir='my-shared-folder'/>
+ </filesystem>
+
<!--BRIDGE-->
<interface type='bridge'>
<source bridge='eth0'/>
diff --git a/src/vbox/vbox_tmpl.c b/src/vbox/vbox_tmpl.c
index 2986f5a..13c324f 100644
--- a/src/vbox/vbox_tmpl.c
+++ b/src/vbox/vbox_tmpl.c
@@ -2249,6 +2249,7 @@ static char *vboxDomainGetXMLDesc(virDomainPtr dom, int flags) {
/* Not supported by libvirt yet */
} else if (device == DeviceType_SharedFolder) {
/* Not supported by libvirt yet */
+ /* Can VirtualBox really boot from a shared folder? */
}
}
@@ -2752,6 +2753,67 @@ static char *vboxDomainGetXMLDesc(virDomainPtr dom, int flags) {
#endif /* VBOX_API_VERSION >= 3001 */
+ /* shared folders */
+ vboxArray sharedFolders = VBOX_ARRAY_INITIALIZER;
+
+ def->nfss = 0;
+
+ vboxArrayGet(&sharedFolders, machine,
+ machine->vtbl->GetSharedFolders);
+
+ if (sharedFolders.count > 0) {
+ if (VIR_ALLOC_N(def->fss, sharedFolders.count) < 0) {
+ virReportOOMError();
+ goto sharedFoldersCleanup;
+ }
+
+ for (i = 0; i < sharedFolders.count; i++) {
+ ISharedFolder *sharedFolder = sharedFolders.items[i];
+ PRUnichar *nameUtf16 = NULL;
+ char *name = NULL;
+ PRUnichar *hostPathUtf16 = NULL;
+ char *hostPath = NULL;
+ PRBool writable = PR_FALSE;
+
+ if (VIR_ALLOC(def->fss[i]) < 0) {
+ virReportOOMError();
+ goto sharedFoldersCleanup;
+ }
+
+ def->fss[i]->type = VIR_DOMAIN_FS_TYPE_MOUNT;
+
+ sharedFolder->vtbl->GetHostPath(sharedFolder, &hostPathUtf16);
+ VBOX_UTF16_TO_UTF8(hostPathUtf16, &hostPath);
+ def->fss[i]->src = strdup(hostPath);
+ VBOX_UTF8_FREE(hostPath);
+ VBOX_UTF16_FREE(hostPathUtf16);
+
+ if (def->fss[i]->src == NULL) {
+ virReportOOMError();
+ goto sharedFoldersCleanup;
+ }
+
+ sharedFolder->vtbl->GetName(sharedFolder, &nameUtf16);
+ VBOX_UTF16_TO_UTF8(nameUtf16, &name);
+ def->fss[i]->dst = strdup(name);
+ VBOX_UTF8_FREE(name);
+ VBOX_UTF16_FREE(nameUtf16);
+
+ if (def->fss[i]->dst == NULL) {
+ virReportOOMError();
+ goto sharedFoldersCleanup;
+ }
+
+ sharedFolder->vtbl->GetWritable(sharedFolder, &writable);
+ def->fss[i]->readonly = !writable;
+
+ ++def->nfss;
+ }
+ }
+
+sharedFoldersCleanup:
+ vboxArrayRelease(&sharedFolders);
+
/* dump network cards if present */
def->nnets = 0;
/* Get which network cards are enabled */
@@ -4790,6 +4852,38 @@ vboxAttachUSB(virDomainDefPtr def, vboxGlobalData *data, IMachine *machine)
}
}
+static void
+vboxAttachSharedFolder(virDomainDefPtr def, vboxGlobalData *data, IMachine *machine)
+{
+ int i;
+ PRUnichar *nameUtf16;
+ PRUnichar *hostPathUtf16;
+ PRBool writable;
+
+ if (def->nfss == 0)
+ return;
+
+ for (i = 0; i < def->nfss; i++) {
+ if (def->fss[i]->type != VIR_DOMAIN_FS_TYPE_MOUNT)
+ continue;
+
+ VBOX_UTF8_TO_UTF16(def->fss[i]->dst, &nameUtf16);
+ VBOX_UTF8_TO_UTF16(def->fss[i]->src, &hostPathUtf16);
+ writable = !def->fss[i]->readonly;
+
+#if VBOX_API_VERSION < 4000
+ machine->vtbl->CreateSharedFolder(machine, nameUtf16, hostPathUtf16,
+ writable);
+#else /* VBOX_API_VERSION >= 4000 */
+ machine->vtbl->CreateSharedFolder(machine, nameUtf16, hostPathUtf16,
+ writable, PR_FALSE);
+#endif /* VBOX_API_VERSION >= 4000 */
+
+ VBOX_UTF16_FREE(nameUtf16);
+ VBOX_UTF16_FREE(hostPathUtf16);
+ }
+}
+
static virDomainPtr vboxDomainDefineXML(virConnectPtr conn, const char *xml) {
VBOX_OBJECT_CHECK(conn, virDomainPtr, NULL);
IMachine *machine = NULL;
@@ -4927,6 +5021,7 @@ static virDomainPtr vboxDomainDefineXML(virConnectPtr conn, const char *xml) {
vboxAttachVideo(def, machine);
vboxAttachDisplay(def, data, machine);
vboxAttachUSB(def, data, machine);
+ vboxAttachSharedFolder(def, data, machine);
/* Save the machine settings made till now and close the
* session. also free up the mchiid variable used.
@@ -5271,6 +5366,34 @@ static int vboxDomainAttachDeviceImpl(virDomainPtr dom,
if (dev->data.hostdev->source.subsys.type == VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_USB) {
}
}
+ } else if (dev->type == VIR_DOMAIN_DEVICE_FS &&
+ dev->data.fs->type == VIR_DOMAIN_FS_TYPE_MOUNT) {
+ PRUnichar *nameUtf16;
+ PRUnichar *hostPathUtf16;
+ PRBool writable;
+
+ VBOX_UTF8_TO_UTF16(dev->data.fs->dst, &nameUtf16);
+ VBOX_UTF8_TO_UTF16(dev->data.fs->src, &hostPathUtf16);
+ writable = !dev->data.fs->readonly;
+
+#if VBOX_API_VERSION < 4000
+ rc = machine->vtbl->CreateSharedFolder(machine, nameUtf16, hostPathUtf16,
+ writable);
+#else /* VBOX_API_VERSION >= 4000 */
+ rc = machine->vtbl->CreateSharedFolder(machine, nameUtf16, hostPathUtf16,
+ writable, PR_FALSE);
+#endif /* VBOX_API_VERSION >= 4000 */
+
+ if (NS_FAILED(rc)) {
+ vboxError(VIR_ERR_INTERNAL_ERROR,
+ _("could not attach shared folder '%s', rc=%08x"),
+ dev->data.fs->dst, (unsigned)rc);
+ } else {
+ ret = 0;
+ }
+
+ VBOX_UTF16_FREE(nameUtf16);
+ VBOX_UTF16_FREE(hostPathUtf16);
}
machine->vtbl->SaveSettings(machine);
VBOX_RELEASE(machine);
@@ -5425,6 +5548,23 @@ static int vboxDomainDetachDevice(virDomainPtr dom, const char *xml) {
if (dev->data.hostdev->source.subsys.type == VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_USB) {
}
}
+ } else if (dev->type == VIR_DOMAIN_DEVICE_FS &&
+ dev->data.fs->type == VIR_DOMAIN_FS_TYPE_MOUNT) {
+ PRUnichar *nameUtf16;
+
+ VBOX_UTF8_TO_UTF16(dev->data.fs->dst, &nameUtf16);
+
+ rc = machine->vtbl->RemoveSharedFolder(machine, nameUtf16);
+
+ if (NS_FAILED(rc)) {
+ vboxError(VIR_ERR_INTERNAL_ERROR,
+ _("could not detach shared folder '%s', rc=%08x"),
+ dev->data.fs->dst, (unsigned)rc);
+ } else {
+ ret = 0;
+ }
+
+ VBOX_UTF16_FREE(nameUtf16);
}
machine->vtbl->SaveSettings(machine);
VBOX_RELEASE(machine);
--
1.7.0.4
13 years
[libvirt] qemu-namespace handling?
by Philipp Hahn
Hello,
some time ago I hand to manipulate the domain XML description using Pythons
Elemtree XML implementation, which had problems generating the right format
for libvirt: elemtree just supports adding Qname elements (that
is "{http://libvirt.org/schemas/domain/qemu/1.0}commandline") which
internally would create a temporary binding of this namespace to the "ns0"
Prefix.
My work-around for Elemtree was the add the name-space mapping for "qemu"
to "http://libvirt.org/schemas/domain/qemu/1.0" to ETs internal mapping table
and add an "xmlns:qemu" attribute by hand:
ET._namespace_map[QEMU_URI] = 'qemu'
domain.attrib['xmlns:qemu'] = QEMU_URI
libvirt on the other hand expects the prefix to be "qemu" and only checks,
that this prefix is bound to the URI mentioned above at the root node).
The following examples would be XML valid, but are not accepted by libvirt:
<domain>...
<qemu:commandline xmlns:qemu="http://libvirt.org/schemas/domain/qemu/1.0">
...</qemu:commandline>
</domain>
<domain xmlns:ns0="http://libvirt.org/schemas/domain/qemu/1.0">...
<ns0:commandline>
...</ns0:commandline>
</domain>
The following (esoteric) example might be wrongly accepted by libvirt
(untested):
<domain xmlns:qemu="http://libvirt.org/schemas/domain/qemu/1.0">
<qemu:commandline xmlns:qemu="urn:foo">
...</qemu:commandline>
</domain>
I don't know if this is worth fixing, but I still encountered the first two
problems myself and had to spend some time to detecting what I did wrong. So
at least I want to share my finding with others, so they don't do the same
mistake.
Sincerely
Philipp Hahn
--
Philipp Hahn Open Source Software Engineer hahn(a)univention.de
Univention GmbH Linux for Your Business fon: +49 421 22 232- 0
Mary-Somerville-Str.1 D-28359 Bremen fax: +49 421 22 232-99
http://www.univention.de/
13 years, 1 month
[libvirt] LPC2011 Virtualization Micro Conf
by Jes Sorensen
Hi,
With the success of last year's Virtualization micro-conference track
at Linux Plumbers 2010, I have accepted to organize a similar track
for Linux Plumbers 2011 in Santa Rosa. Please see the official Linux
Plumbers 2011 website for full details about the conference:
http://www.linuxplumbersconf.org/2011/
The Linux Plumbers 2011 Virtualization track is focusing on general
free software Linux Virtualization. It is not reserved for a specific
hypervisor, but will focus on general virtualization issues and in
particular collaboration amongst projects. This would include KVM,
Xen, QEMU, containers etc.
Deadline:
---------
The deadline for submissions is April 30th. Please visit the following
link to submit your proposal:
http://www.linuxplumbersconf.org/2011/ocw/events/LPC2011MC/proposals
Example topics:
---------------
- Kernel and Hypervisor KVM/QEMU/Xen interaction
- QEMU integration, sharing of code between the different projects
- IO Performance and scalability
- Live Migration
- Managing and supporting enterprise storage
- Support for new hardware features, and/or provide guest access to
these features.
- Guest agents
- Virtualization management tools, libvirt, etc.
- Desktop integration
- Consumer Electronics device emulation
- Custom platform configuration and coordination with the kernel
Audience:
---------
Virtualization hypervisor developers, developers of virtualization
management tools and applications, embedded virtualization developers,
vendors and others.
Best regards,
Jes
13 years, 1 month
[libvirt] libvirt(-java): virDomainMigrateSetMaxDowntime
by Thomas Treutner
Hi,
I'm facing some troubles with virDomainMigrate &
virDomainMigrateSetMaxDowntime. The core problem is that KVM's default
value for the maximum allowed downtime is 30ms (max_downtime in
migration.c, it's nanoseconds there; 0.12.3) which is too low for my VMs
when they're busy (~50% CPU util and above). Migrations then take
literally forever, I had to abort them after 15 minutes or so. I'm using
GBit Ethernet, so plenty bandwidth should be available. Increasing the
allowed downtime to 50ms seems to help, but I have not tested situations
where the VM is completely utilized. Anyways, the default value is too
low for me, so I tried virDomainMigrateSetMaxDowntime resp. the Java
wrapper function.
Here I'm facing a problem I can overcome only with a quite crude hack:
org.libvirt.Domain.migrate(..) blocks until the migration is done, which
is of course reasonable. So I tried calling migrateSetMaxDowntime(..)
before migrating, causing an error:
"Requested operation is not valid: domain is not being migrated"
This tells me that calling migrateSetMaxDowntime is only allowed during
migrations. As I'm migrating VMs automatically and without any user
intervention I'd need to create some glue code that runs in an extra
thread, waiting "some time" hoping that the migration was kicked off in
the main thread yet and then calling migrateSetMaxDowntime. I'd like to
avoid such quirks in the long run, if possible.
So my question: Would it be possible to extend the migrate() method
resp. virDomainMigrate() function with an optional maxDowntime parameter
that is passed down as QEMU_JOB_SIGNAL_MIGRATE_DOWNTIME so that
qemuDomainWaitForMigrationComplete would set the value? Or are there
easier ways?
Thanks and regards,
-t
13 years, 2 months
