[Libvir] save and restore guest
hi, if i use xen with xendomain it's possible to save and restore guest state. if i use libvirt it's not working (at least by default with kvm). i mean if i stop or restart libvirtd all guests a stopped and even if i restart libvirtd i've to start all guests manually. imho this's a very essential feature. what is the reason this not working with libvirtd?: - this feature is missing from libvirtd? or - this feature is not turned on by default? or - this feature is missing from kvm/qemu? or something else? thanks in advance. -- Levente "Si vis pacem para bellum!"
On Sat, Oct 06, 2007 at 02:29:39PM +0200, Farkas Levente wrote:
hi, if i use xen with xendomain it's possible to save and restore guest state. if i use libvirt it's not working (at least by default with kvm). i mean if i stop or restart libvirtd all guests a stopped and even if i restart libvirtd i've to start all guests manually. imho this's a very essential feature. what is the reason this not working with libvirtd?: - this feature is missing from libvirtd? or
You can set KVM/QEMU guests to autostart with virsh autostart {NAME|ID|UUID}
- this feature is not turned on by default? or
Yep, guests don't autostart by default. Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|
Daniel P. Berrange wrote:
On Sat, Oct 06, 2007 at 02:29:39PM +0200, Farkas Levente wrote:
hi, if i use xen with xendomain it's possible to save and restore guest state. if i use libvirt it's not working (at least by default with kvm). i mean if i stop or restart libvirtd all guests a stopped and even if i restart libvirtd i've to start all guests manually. imho this's a very essential feature. what is the reason this not working with libvirtd?: - this feature is missing from libvirtd? or
You can set KVM/QEMU guests to autostart with
virsh autostart {NAME|ID|UUID}
thanks, but go back to my first question. afais /etc/init.d/libvirtd simple kill libvirtd, but virsh has a command save/restore. wouldn't be it's much better to save guest's state on stop, restore on start in stead of start if there is a saved state. i can send a patch to the /etc/init.d/libvirtd, just would like to know is there any reason it's not that way? anyway xendomains do it in the save way. -- Levente "Si vis pacem para bellum!"
On Mon, Oct 08, 2007 at 04:27:00PM +0200, Farkas Levente wrote:
Daniel P. Berrange wrote:
On Sat, Oct 06, 2007 at 02:29:39PM +0200, Farkas Levente wrote:
hi, if i use xen with xendomain it's possible to save and restore guest state. if i use libvirt it's not working (at least by default with kvm). i mean if i stop or restart libvirtd all guests a stopped and even if i restart libvirtd i've to start all guests manually. imho this's a very essential feature. what is the reason this not working with libvirtd?: - this feature is missing from libvirtd? or
You can set KVM/QEMU guests to autostart with
virsh autostart {NAME|ID|UUID}
thanks, but go back to my first question. afais /etc/init.d/libvirtd simple kill libvirtd, but virsh has a command save/restore. wouldn't be it's much better to save guest's state on stop, restore on start in stead of start if there is a saved state. i can send a patch to the /etc/init.d/libvirtd, just would like to know is there any reason it's not that way? anyway xendomains do it in the save way.
The save/restore capability is currently only available in the KVM-ified version of QEMU. We could make it try to save, and failing that destroy the guest. The xendomains scripts isn't a good model to emulate though. The autostart/kill functionality is part of the libvirt daemon itself. Any save/restore capability would be best integrated there Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|
Daniel P. Berrange wrote:
On Mon, Oct 08, 2007 at 04:27:00PM +0200, Farkas Levente wrote:
On Sat, Oct 06, 2007 at 02:29:39PM +0200, Farkas Levente wrote:
hi, if i use xen with xendomain it's possible to save and restore guest state. if i use libvirt it's not working (at least by default with kvm). i mean if i stop or restart libvirtd all guests a stopped and even if i restart libvirtd i've to start all guests manually. imho this's a very essential feature. what is the reason this not working with libvirtd?: - this feature is missing from libvirtd? or You can set KVM/QEMU guests to autostart with
virsh autostart {NAME|ID|UUID}
Daniel P. Berrange wrote: thanks, but go back to my first question. afais /etc/init.d/libvirtd simple kill libvirtd, but virsh has a command save/restore. wouldn't be it's much better to save guest's state on stop, restore on start in stead of start if there is a saved state. i can send a patch to the /etc/init.d/libvirtd, just would like to know is there any reason it's not that way? anyway xendomains do it in the save way.
The save/restore capability is currently only available in the KVM-ified version of QEMU. We could make it try to save, and failing that destroy the guest. The xendomains scripts isn't a good model to emulate though. The autostart/kill functionality is part of the libvirt daemon itself. Any save/restore capability would be best integrated there
for those who like to save and restore guest at libvirtd stop and start i attached a patch we use to for it. it's based on xen's sripts. LIBVIRTD_AUTO_ONLY still not implemented but the sysconfig file already contains it. if you like to set the default behavior to the current then set LIBVIRTD_RESTORE to false. imho it'd be useful to include in the upstream libvirtd too. -- Levente "Si vis pacem para bellum!"
Farkas Levente wrote:
Daniel P. Berrange wrote:
On Sat, Oct 06, 2007 at 02:29:39PM +0200, Farkas Levente wrote:
hi, if i use xen with xendomain it's possible to save and restore guest state. if i use libvirt it's not working (at least by default with kvm). i mean if i stop or restart libvirtd all guests a stopped and even if i restart libvirtd i've to start all guests manually. imho this's a very essential feature. what is the reason this not working with libvirtd?: - this feature is missing from libvirtd? or You can set KVM/QEMU guests to autostart with
virsh autostart {NAME|ID|UUID}
Daniel P. Berrange wrote: thanks, but go back to my first question. afais /etc/init.d/libvirtd simple kill libvirtd, but virsh has a command save/restore. wouldn't be it's much better to save guest's state on stop, restore on start in stead of start if there is a saved state. i can send a patch to the /etc/init.d/libvirtd, just would like to know is there any reason it's not that way? anyway xendomains do it in the save way. The save/restore capability is currently only available in the KVM-ified version of QEMU. We could make it try to save, and failing that destroy
On Mon, Oct 08, 2007 at 04:27:00PM +0200, Farkas Levente wrote: the guest. The xendomains scripts isn't a good model to emulate though. The autostart/kill functionality is part of the libvirt daemon itself. Any save/restore capability would be best integrated there
for those who like to save and restore guest at libvirtd stop and start i attached a patch we use to for it. it's based on xen's sripts. LIBVIRTD_AUTO_ONLY still not implemented but the sysconfig file already contains it. if you like to set the default behavior to the current then set LIBVIRTD_RESTORE to false. imho it'd be useful to include in the upstream libvirtd too.
and the patch:-) -- Levente "Si vis pacem para bellum!"
On Fri, Oct 19, 2007 at 01:56:10PM +0200, Farkas Levente wrote:
Farkas Levente wrote:
Daniel P. Berrange wrote:
The save/restore capability is currently only available in the KVM-ified version of QEMU. We could make it try to save, and failing that destroy the guest. The xendomains scripts isn't a good model to emulate though. The autostart/kill functionality is part of the libvirt daemon itself. Any save/restore capability would be best integrated there
for those who like to save and restore guest at libvirtd stop and start i attached a patch we use to for it. it's based on xen's sripts. LIBVIRTD_AUTO_ONLY still not implemented but the sysconfig file already contains it. if you like to set the default behavior to the current then set LIBVIRTD_RESTORE to false. imho it'd be useful to include in the upstream libvirtd too.
and the patch:-)
As I mentioned above, doing this in the init script is a bad idea because it does not interact well with domain autostart. The libvirt dameon itself will autostart domains when it starts. So you may be saving the guests at shutdown, but at the next boot any which are marked autostart will be started fresh & the subsequent restore for them will fail since they are already running. Doing this all correctly requires doing it in the daemon not the initscript. Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|
Daniel P. Berrange wrote:
On Fri, Oct 19, 2007 at 01:56:10PM +0200, Farkas Levente wrote:
Farkas Levente wrote:
Daniel P. Berrange wrote:
The save/restore capability is currently only available in the KVM-ified version of QEMU. We could make it try to save, and failing that destroy the guest. The xendomains scripts isn't a good model to emulate though. The autostart/kill functionality is part of the libvirt daemon itself. Any save/restore capability would be best integrated there for those who like to save and restore guest at libvirtd stop and start i attached a patch we use to for it. it's based on xen's sripts. LIBVIRTD_AUTO_ONLY still not implemented but the sysconfig file already contains it. if you like to set the default behavior to the current then set LIBVIRTD_RESTORE to false. imho it'd be useful to include in the upstream libvirtd too.
and the patch:-)
As I mentioned above, doing this in the init script is a bad idea because it does not interact well with domain autostart. The libvirt dameon itself will autostart domains when it starts. So you may be saving the guests at shutdown, but at the next boot any which are marked autostart will be started fresh & the subsequent restore for them will fail since they are already running. Doing this all correctly requires doing it in the daemon not the initscript.
yes, but currently it's not implemented:-( but if you don't autostart any guest (which is the current default) my patch at least working until it'll be implemented. -- Levente "Si vis pacem para bellum!"
Farkas Levente wrote:
Daniel P. Berrange wrote:
On Fri, Oct 19, 2007 at 01:56:10PM +0200, Farkas Levente wrote:
Farkas Levente wrote:
Daniel P. Berrange wrote:
The save/restore capability is currently only available in the KVM-ified version of QEMU. We could make it try to save, and failing that destroy the guest. The xendomains scripts isn't a good model to emulate though. The autostart/kill functionality is part of the libvirt daemon itself. Any save/restore capability would be best integrated there for those who like to save and restore guest at libvirtd stop and start i attached a patch we use to for it. it's based on xen's sripts. LIBVIRTD_AUTO_ONLY still not implemented but the sysconfig file already contains it. if you like to set the default behavior to the current then set LIBVIRTD_RESTORE to false. imho it'd be useful to include in the upstream libvirtd too.
and the patch:-) As I mentioned above, doing this in the init script is a bad idea because it does not interact well with domain autostart. The libvirt dameon itself will autostart domains when it starts. So you may be saving the guests at shutdown, but at the next boot any which are marked autostart will be started fresh & the subsequent restore for them will fail since they are already running. Doing this all correctly requires doing it in the daemon not the initscript.
yes, but currently it's not implemented:-( but if you don't autostart any guest (which is the current default) my patch at least working until it'll be implemented.
The problem is that if we put in your patch, we add a set of configuration options which we'll have to keep supporting forever, even when the 'proper' solution is done (whatever that might be). Rich. -- Emerging Technologies, Red Hat - http://et.redhat.com/~rjones/ Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 03798903
Richard W.M. Jones wrote:
Farkas Levente wrote:
Daniel P. Berrange wrote:
On Fri, Oct 19, 2007 at 01:56:10PM +0200, Farkas Levente wrote:
Farkas Levente wrote:
The save/restore capability is currently only available in the KVM-ified version of QEMU. We could make it try to save, and failing that destroy the guest. The xendomains scripts isn't a good model to emulate though. The autostart/kill functionality is part of the libvirt daemon itself. Any save/restore capability would be best integrated there for those who like to save and restore guest at libvirtd stop and start i attached a patch we use to for it. it's based on xen's sripts. LIBVIRTD_AUTO_ONLY still not implemented but the sysconfig file already contains it. if you like to set the default behavior to the current
Daniel P. Berrange wrote: then set LIBVIRTD_RESTORE to false. imho it'd be useful to include in the upstream libvirtd too.
and the patch:-) As I mentioned above, doing this in the init script is a bad idea because it does not interact well with domain autostart. The libvirt dameon itself will autostart domains when it starts. So you may be saving the guests at shutdown, but at the next boot any which are marked autostart will be started fresh & the subsequent restore for them will fail since they are already running. Doing this all correctly requires doing it in the daemon not the initscript.
yes, but currently it's not implemented:-( but if you don't autostart any guest (which is the current default) my patch at least working until it'll be implemented.
The problem is that if we put in your patch, we add a set of configuration options which we'll have to keep supporting forever, even when the 'proper' solution is done (whatever that might be).
i can argue with that any 0.x version should have to be compatible with any earlier versions. but at least i can use it until then:-) -- Levente "Si vis pacem para bellum!"
On Mon, Oct 22, 2007 at 12:53:48PM +0200, Farkas Levente wrote:
Richard W.M. Jones wrote:
Farkas Levente wrote:
Daniel P. Berrange wrote:
As I mentioned above, doing this in the init script is a bad idea because it does not interact well with domain autostart. The libvirt dameon itself will autostart domains when it starts. So you may be saving the guests at shutdown, but at the next boot any which are marked autostart will be started fresh & the subsequent restore for them will fail since they are already running. Doing this all correctly requires doing it in the daemon not the initscript.
yes, but currently it's not implemented:-( but if you don't autostart any guest (which is the current default) my patch at least working until it'll be implemented.
The problem is that if we put in your patch, we add a set of configuration options which we'll have to keep supporting forever, even when the 'proper' solution is done (whatever that might be).
i can argue with that any 0.x version should have to be compatible with any earlier versions.
There is simply no question of including this code in libvirt. It does work in the general case & does not even get us incrementally towards the general case. Including a half-baked solution which we would need to throw out in the future & start from scratch is not sustainable. Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|
participants (3)
-
Daniel P. Berrange -
Farkas Levente -
Richard W.M. Jones