[libvirt-users] Using virsh to load scripts for the guest machine
Right on the top of http://www.centos.org/docs/5/html/5.2/Virtualization/chap-Virtualization-Man..., it seems to imply you can load/send scripts to the vm guest using virsh. Is that possible? How and what are the limitations? Can you query the vm guest?
On 07/15/2012 07:52 PM, Mauricio Tavares wrote:
Right on the top of http://www.centos.org/docs/5/html/5.2/Virtualization/chap-Virtualization-Man..., it seems to imply you can load/send scripts to the vm guest using virsh. Is that possible? How and what are the limitations? Can you query the vm guest?
What type of scripts are you talking about? You may be thinking more about the capabilities of what libguestfs provides, for modifying disk images. In general, virsh itself controls how to start a guest, but not the additional layers of communication (such as virtio, qemu-ga, or the libguestfs appliance app) required for a host to command a guest to do something from within the guest. -- Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
On Mon, Jul 30, 2012 at 1:50 PM, Eric Blake <eblake@redhat.com> wrote:
On 07/15/2012 07:52 PM, Mauricio Tavares wrote:
Right on the top of http://www.centos.org/docs/5/html/5.2/Virtualization/chap-Virtualization-Man..., it seems to imply you can load/send scripts to the vm guest using virsh. Is that possible? How and what are the limitations? Can you query the vm guest?
What type of scripts are you talking about? You may be thinking more about the capabilities of what libguestfs provides, for modifying disk images. In general, virsh itself controls how to start a guest, but not the additional layers of communication (such as virtio, qemu-ga, or the libguestfs appliance app) required for a host to command a guest to do something from within the guest.
Basic one would be in case a machine has been paused for a long time. You know as in "hey, you lazy vm! You have been sleeping for two weeks! Now your clock is way off and poor ntp can't sync it back. So, here's current date!" So that could either be done by stopping ntp and running ntpdate or actually being able to pass the host time (adjusted for the timezone the vm is supposed to be at) to the vm.
-- Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
Hi Mauricio, Perhaps the following link is what you want: http://libvirt.org/formatdomain.html#elementsTime (Time keeping) -- Regards, Alex ----- Original Message ----- From: "Mauricio Tavares" <raubvogel@gmail.com> To: "libvirt-users" <libvirt-users@redhat.com> Sent: Tuesday, July 31, 2012 2:00:40 AM Subject: Re: [libvirt-users] Using virsh to load scripts for the guest machine On Mon, Jul 30, 2012 at 1:50 PM, Eric Blake <eblake@redhat.com> wrote:
On 07/15/2012 07:52 PM, Mauricio Tavares wrote:
Right on the top of http://www.centos.org/docs/5/html/5.2/Virtualization/chap-Virtualization-Man..., it seems to imply you can load/send scripts to the vm guest using virsh. Is that possible? How and what are the limitations? Can you query the vm guest?
What type of scripts are you talking about? You may be thinking more about the capabilities of what libguestfs provides, for modifying disk images. In general, virsh itself controls how to start a guest, but not the additional layers of communication (such as virtio, qemu-ga, or the libguestfs appliance app) required for a host to command a guest to do something from within the guest.
Basic one would be in case a machine has been paused for a long time. You know as in "hey, you lazy vm! You have been sleeping for two weeks! Now your clock is way off and poor ntp can't sync it back. So, here's current date!" So that could either be done by stopping ntp and running ntpdate or actually being able to pass the host time (adjusted for the timezone the vm is supposed to be at) to the vm.
-- Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
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On 07/30/2012 12:00 PM, Mauricio Tavares wrote:
On Mon, Jul 30, 2012 at 1:50 PM, Eric Blake <eblake@redhat.com> wrote:
On 07/15/2012 07:52 PM, Mauricio Tavares wrote:
Right on the top of http://www.centos.org/docs/5/html/5.2/Virtualization/chap-Virtualization-Man..., it seems to imply you can load/send scripts to the vm guest using virsh. Is that possible? How and what are the limitations? Can you query the vm guest?
What type of scripts are you talking about? You may be thinking more about the capabilities of what libguestfs provides, for modifying disk images. In general, virsh itself controls how to start a guest, but not the additional layers of communication (such as virtio, qemu-ga, or the libguestfs appliance app) required for a host to command a guest to do something from within the guest.
Basic one would be in case a machine has been paused for a long time. You know as in "hey, you lazy vm! You have been sleeping for two weeks! Now your clock is way off and poor ntp can't sync it back. So, here's current date!"
That is something that fits better through qemu-ga, but no one has implemented it yet (cc'ing qemu-devel in case I'm misrepresenting things). Of course, if we did have a qemu-ga command for pushing the current time into the guest, then libvirt could usefully expose an API to wrap that qemu-ga command. -- Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
Eric Blake <eblake@redhat.com> writes:
On 07/30/2012 12:00 PM, Mauricio Tavares wrote:
On Mon, Jul 30, 2012 at 1:50 PM, Eric Blake <eblake@redhat.com> wrote:
On 07/15/2012 07:52 PM, Mauricio Tavares wrote:
Right on the top of http://www.centos.org/docs/5/html/5.2/Virtualization/chap-Virtualization-Man..., it seems to imply you can load/send scripts to the vm guest using virsh. Is that possible? How and what are the limitations? Can you query the vm guest?
What type of scripts are you talking about? You may be thinking more about the capabilities of what libguestfs provides, for modifying disk images. In general, virsh itself controls how to start a guest, but not the additional layers of communication (such as virtio, qemu-ga, or the libguestfs appliance app) required for a host to command a guest to do something from within the guest.
Basic one would be in case a machine has been paused for a long time. You know as in "hey, you lazy vm! You have been sleeping for two weeks! Now your clock is way off and poor ntp can't sync it back. So, here's current date!"
That is something that fits better through qemu-ga, but no one has implemented it yet (cc'ing qemu-devel in case I'm misrepresenting things). Of course, if we did have a qemu-ga command for pushing the current time into the guest, then libvirt could usefully expose an API to wrap that qemu-ga command.
Could you setup a wiki page on qemu.org with a list of qemu-ga commands that libvirt would like? Adding commands is pretty trivial so if ya'll have a list of things you'd like, they're great quick tasks that we can find folks to work on. Regards, Anthony Liguori
-- Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
On 08/01/2012 07:48 AM, Anthony Liguori wrote:
Basic one would be in case a machine has been paused for a long time. You know as in "hey, you lazy vm! You have been sleeping for two weeks! Now your clock is way off and poor ntp can't sync it back. So, here's current date!"
That is something that fits better through qemu-ga, but no one has implemented it yet (cc'ing qemu-devel in case I'm misrepresenting things). Of course, if we did have a qemu-ga command for pushing the current time into the guest, then libvirt could usefully expose an API to wrap that qemu-ga command.
Could you setup a wiki page on qemu.org with a list of qemu-ga commands that libvirt would like?
I gave it a shot (feel free to improve it) http://wiki.qemu.org/Features/GuestAgent/UsefulCommands -- Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
On Wed, Aug 1, 2012 at 7:17 PM, Eric Blake <eblake@redhat.com> wrote:
On 08/01/2012 07:48 AM, Anthony Liguori wrote:
Basic one would be in case a machine has been paused for a long time. You know as in "hey, you lazy vm! You have been sleeping for two weeks! Now your clock is way off and poor ntp can't sync it back. So, here's current date!"
That is something that fits better through qemu-ga, but no one has implemented it yet (cc'ing qemu-devel in case I'm misrepresenting things). Of course, if we did have a qemu-ga command for pushing the current time into the guest, then libvirt could usefully expose an API to wrap that qemu-ga command.
Could you setup a wiki page on qemu.org with a list of qemu-ga commands that libvirt would like?
I gave it a shot (feel free to improve it) http://wiki.qemu.org/Features/GuestAgent/UsefulCommands
Dumb question: how do I create an account so I too can do some editing?
-- Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
participants (4)
-
Alex Jia -
Anthony Liguori -
Eric Blake -
Mauricio Tavares