8:01 p.m.
Hello,
this thread last year (started by me... ;-) was very useful in different
aspects involved
http://lists.ovirt.org/pipermail/users/2017-March/080322.html
We did cover memory save or not and fsfreeze automatically done by guest
agent if installed inside the VM.
What about pre-snapshot scripts/operations to run inside guest, to have
application consistency?
Eg if I have a database inside the VM and I have scripted my backup job
involving live-snapshot (eg with the backup.py utility of the thread)
Can I leverage this kind of functionality with the oVirt guest agent?
Or is it mandatory to consider a remote connection to the VM (via ssh or
what for windows?) and execute the script/command/bat file?
What are you curently doing in this respect?
Thanks,
Gianluca
9:54 p.m.
On Mar 6, 2018 7:02 PM, "Gianluca Cecchi" <gianluca.cecchi(a)gmail.com>
wrote:
Hello,
this thread last year (started by me... ;-) was very useful in different
aspects involved
http://lists.ovirt.org/pipermail/users/2017-March/080322.html
We did cover memory save or not and fsfreeze automatically done by guest
agent if installed inside the VM.
What about pre-snapshot scripts/operations to run inside guest, to have
application consistency?
Eg if I have a database inside the VM and I have scripted my backup job
involving live-snapshot (eg with the backup.py utility of the thread)
https://github.com/guillon/qemu-plugins/blob/master/scripts/qemu-guest-ag...
Y.
Can I leverage this kind of functionality with the oVirt guest agent?
Or is it mandatory to consider a remote connection to the VM (via ssh or
what for windows?) and execute the script/command/bat file?
What are you curently doing in this respect?
Thanks,
Gianluca
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1:47 a.m.
On Tue, Mar 6, 2018 at 7:54 PM, Yaniv Kaul <ykaul(a)redhat.com> wrote:
On Mar 6, 2018 7:02 PM, "Gianluca Cecchi" <gianluca.cecchi(a)gmail.com>
wrote:
Hello,
this thread last year (started by me... ;-) was very useful in different
aspects involved
http://lists.ovirt.org/pipermail/users/2017-March/080322.html
We did cover memory save or not and fsfreeze automatically done by guest
agent if installed inside the VM.
What about pre-snapshot scripts/operations to run inside guest, to have
application consistency?
Eg if I have a database inside the VM and I have scripted my backup job
involving live-snapshot (eg with the backup.py utility of the thread)
https://github.com/guillon/qemu-plugins/blob/master/scripts/
qemu-guest-agent/fsfreeze-hook.d/mysql-flush.sh.sample
Hello Yaniv,
thanks for the information and the example file link.
So I have understood that the freeze-hook script is run with the "freeze"
option before snapshot and again but with the "thaw" option after the
snapshot.
So I can manage what to do, parsing the argument given
So far so good.
I have tested with a Fedora 27 guest and all is ok there.
Now I would like to do something similar for a Windows 2008 R2 x64 VM.
I see that the qemu-guest-agent has been installed under
C:\Programs\qemu-ga and that the "QEMU Guest Agent" service is run as
"C:\Program Files\qemu-ga\qemu-ga.exe" -d
In fact I see I have a registry key in
HKLM\SYSTEM\CurrentControlSet\services\QEMU-GA
with the same value above for ImagePath ;
"C:\Program Files\qemu-ga\qemu-ga.exe" -d
What should I do to enable a freeze-hook script on Windows now?
BTW: searching around while trying to understand more, I found that:
on hypervisor running the VM I have
# vdsClient -s 0 getVmStats vm_guid
that works and gives me information that confirms agent seems to
communicate and I get also
appsList = [.... , 'QEMU guest agent', ...]
Also, the dump of the dynamic xml for the guest contains
# virsh -r dumpxml VM_NAME
<channel type='unix'>
<source mode='bind'
path='/var/lib/libvirt/qemu/channels/420e5014-9b26-a4c0-9d79-ed9b123304de.org.qemu.guest_agent.0'/>
<target type='virtio' name='org.qemu.guest_agent.0'
state='connected'/>
<alias name='channel1'/>
<address type='virtio-serial' controller='0' bus='0'
port='2'/>
</channel>
I tried to get its settings from qemu guest agent using socat and unix
domain sockets but I don't receive answer
# socat unix-connect:/
var/lib/libvirt/qemu/channels/420e5014-9b26-a4c0-9d79-ed9b123304de.org.qemu.guest_agent.0
readline
and then in the interactive prompt
{"execute":"guest-info"}
to get and verify information about fsfreeze, something like
...., {"enabled": true, "name": "guest-fsfreeze-freeze"},
... ....,
{"enabled": true, "name": "guest-fsfreeze-thaw"}, ...
But I didn't get any line....
Is this communication from OS disabled by design out of oVirt mgmt?
Thanks again for any info to configure freeze-hook in Windows guest.
Gianluca
11:47 a.m.
On Thu, Mar 8, 2018 at 12:47 AM, Gianluca Cecchi <gianluca.cecchi(a)gmail.com>
wrote:
On Tue, Mar 6, 2018 at 7:54 PM, Yaniv Kaul <ykaul(a)redhat.com>
wrote:
>
>
> On Mar 6, 2018 7:02 PM, "Gianluca Cecchi"
<gianluca.cecchi(a)gmail.com>
> wrote:
>
> Hello,
> this thread last year (started by me... ;-) was very useful in different
> aspects involved
>
> http://lists.ovirt.org/pipermail/users/2017-March/080322.html
>
> We did cover memory save or not and fsfreeze automatically done by guest
> agent if installed inside the VM.
> What about pre-snapshot scripts/operations to run inside guest, to have
> application consistency?
> Eg if I have a database inside the VM and I have scripted my backup job
> involving live-snapshot (eg with the backup.py utility of the thread)
>
>
> https://github.com/guillon/qemu-plugins/blob/master/scripts/
> qemu-guest-agent/fsfreeze-hook.d/mysql-flush.sh.sample
>
>
>
Hello Yaniv,
thanks for the information and the example file link.
So I have understood that the freeze-hook script is run with the "freeze"
option before snapshot and again but with the "thaw" option after the
snapshot.
So I can manage what to do, parsing the argument given
So far so good.
I have tested with a Fedora 27 guest and all is ok there.
Now I would like to do something similar for a Windows 2008 R2 x64 VM.
Windows is somewhat different. In fact, it's a bit better than Linux (ARGH!
but it's true) with its support for VSS - an API for applications to
register to events such as backup.
You should have the QEMU guest agent VSS provider installed (Note: need to
see where's the latest bits - I found[1]).
Then, if your application supports VSS, you are all good (I believe).
Y.
[1]
https://fedorapeople.org/groups/virt/virtio-win/direct-downloads/archive-...
I see that the qemu-guest-agent has been installed under
C:\Programs\qemu-ga and that the "QEMU Guest Agent" service
is run as
"C:\Program Files\qemu-ga\qemu-ga.exe" -d
In fact I see I have a registry key in
HKLM\SYSTEM\CurrentControlSet\services\QEMU-GA
with the same value above for ImagePath ;
"C:\Program Files\qemu-ga\qemu-ga.exe" -d
What should I do to enable a freeze-hook script on Windows now?
BTW: searching around while trying to understand more, I found that:
on hypervisor running the VM I have
# vdsClient -s 0 getVmStats vm_guid
that works and gives me information that confirms agent seems to
communicate and I get also
appsList = [.... , 'QEMU guest agent', ...]
Also, the dump of the dynamic xml for the guest contains
# virsh -r dumpxml VM_NAME
<channel type='unix'>
<source mode='bind' path='/var/lib/libvirt/qemu/
channels/420e5014-9b26-a4c0-9d79-ed9b123304de.org.qemu.guest_agent.0'/>
<target type='virtio' name='org.qemu.guest_agent.0'
state='connected'/>
<alias name='channel1'/>
<address type='virtio-serial' controller='0' bus='0'
port='2'/>
</channel>
I tried to get its settings from qemu guest agent using socat and unix
domain sockets but I don't receive answer
# socat unix-connect:/var/lib/libvirt/qemu/channels/420e5014-9b26-
a4c0-9d79-ed9b123304de.org.qemu.guest_agent.0 readline
and then in the interactive prompt
{"execute":"guest-info"}
to get and verify information about fsfreeze, something like
...., {"enabled": true, "name": "guest-fsfreeze-freeze"},
... ....,
{"enabled": true, "name": "guest-fsfreeze-thaw"}, ...
But I didn't get any line....
Is this communication from OS disabled by design out of oVirt mgmt?
Thanks again for any info to configure freeze-hook in Windows guest.
Gianluca
4:24 p.m.
On Thu, Mar 8, 2018 at 9:47 AM, Yaniv Kaul <ykaul(a)redhat.com> wrote:
>
> Now I would like to do something similar for a Windows 2008 R2 x64 VM.
>
Windows is somewhat different. In fact, it's a bit better than Linux
(ARGH! but it's true) with its support for VSS - an API for applications to
register to events such as backup.
You should have the QEMU guest agent VSS provider installed (Note: need to
see where's the latest bits - I found[1]).
Then, if your application supports VSS, you are all good (I believe).
Y.
[1] https://fedorapeople.org/groups/virt/virtio-win/direct-
downloads/archive-qemu-ga/qemu-ga-win-7.4.5-1/
>
>
Yes, I see that there are some VSS events intercepted in event viewer when
I run a snapshot.
But in my particulr case I have an Oracle database used for Business
Intelligence that for performance reasons is not in archive log mode, so it
can't interact with VSS layer.
Due to its nature I can shutdown this database during the evening and then
reopen it before the ETL processing happens during the night.
So in that time frame I would like to have a pre-snapshot operation of
shutdown db and post-snapshot operation of start db.
And then I clone the snapshot and export it in case I have to restore the
"blob" as a consistent whole
It is for this reason that I'm trying to verify if the freeze-hook is
usable also in WIndows environments (based on some threads I find it should
be...)
Thanks,
Gianluca
2451
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4 comments
2 participants
participants (2)
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Gianluca Cecchi -
Yaniv Kaul