10:14 a.m.
Dear Friends,
I would ask you a question ; grateful in advance!
I have a program running on a VM guest. Its output is valuable (for VM introspection) so I
want to let the host module know about it. I prefer to redirect ' stdio" of a
guest into a device at the host (a text file or my device that has the name
"mydev"
and the driver is written for it).
I have the XML definition file for my VM in /etc/libvirt/qemu. I have added the section:
<serial type="file">
<source path="/var/log/vm/vml.log"/>
<target port="0"/>
</serial>
into the /devices section.
That is I want the stdio to be streamed into the file /var/log/vm/vml.log at the host.
Then I run simple textual commands at the guest (ls, pwd and so on). But I do not see
/var/log/vm/vml.log created at the host.
Please help me.
Thanks in advance,
Alexander Binun
The command string for qemu will look like qemu -serial /dev/mydev ... But I would like
to
modify the libvirt definition XML file (in /etc/libvirt/qemu). Stefan notes in his blog
(http://blog.vmsplice.net/2011/04/how-to-pass-qemu-command-line-options.html) that the
options will
look like:
---------- Forwarded message ----------
Date: Wed, 28 May 2014 18:06:10 +0300
From: Eric Blake <eblake(a)redhat.com>
To: Alexander Binun <binun(a)cs.bgu.ac.il>
Cc: Stefan Hajnoczi <stefanha(a)gmail.com>
yagel(a)cs.bgu.ac.il
kahilm(a)post.bgu.ac.il
qemu-devel(a)nongnu.org
boaz.menuhin(a)gmail.com
Paolo Bonzini <pbonzini(a)redhat.com>
markbl(a)post.bgu.ac.il
Subject: Re: excuse me for incorrect question...
On 05/28/2014 08:43 AM, Alexander Binun wrote:
Eric, I aplogize for making your work complicated.
[You top-posted again]
No need to apologize - these lists exist to help people, and we were all
new once.
Should I send questions to libvirt-users(a)redhat.com instead ? I would ask more questions.
Yes, if your questions are related to libvirt, then asking on a libvirt
list will get you a better audience that may have better answers to your
questions.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
On 05/28/2014 08:43 AM, Alexander Binun wrote:
Eric, I aplogize for making your work complicated.
[You top-posted again]
No need to apologize - these lists exist to help people, and we were all
new once.
Should I send questions to libvirt-users(a)redhat.com instead ? I would ask more
questions.
Yes, if your questions are related to libvirt, then asking on a libvirt
list will get you a better audience that may have better answers to your
questions.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
12:28 p.m.
On 05/28/2014 09:14 AM, Alexander Binun wrote:
[can you convince your mailer to wrap long lines?]
I have a program running on a VM guest. Its output is valuable (for VM introspection) so
I want to let the host module know about it. I prefer to redirect ' stdio" of a
guest into a device at the host (a text file or my device that has the name
"mydev"
and the driver is written for it).
I have the XML definition file for my VM in /etc/libvirt/qemu. I have added the section:
<serial type="file">
<source path="/var/log/vm/vml.log"/>
<target port="0"/>
</serial>
into the /devices section.
That is I want the stdio to be streamed into the file /var/log/vm/vml.log at the host.
Then I run simple textual commands at the guest (ls, pwd and so on).
How are you getting into your guest to run those commands? Did you
connect to your guest's serial console, or is it in a gui window, or via
an ssh session, or...? Are you sure the commands you are executing have
the guest's /dev/ttyS0 as their stdout?
But I do not see /var/log/vm/vml.log created at the host.
I'm not sure whether libvirt will pre-create the file, or whether it
insists that the file already exists. Maybe others can chime in. I know
Dave Allan has done some work with python scripts that faithfully
capture all text output to the guest's serial console, although I don't
have a handy link to that sample script.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
1:44 p.m.
On Wed, May 28, 2014 at 11:28:19AM -0600, Eric Blake wrote:
On 05/28/2014 09:14 AM, Alexander Binun wrote:
[can you convince your mailer to wrap long lines?]
>
> I have a program running on a VM guest. Its output is valuable (for VM
introspection) so I want to let the host module know about it. I prefer to redirect '
stdio" of a guest into a device at the host (a text file or my device that has the
name "mydev"
> and the driver is written for it).
>
> I have the XML definition file for my VM in /etc/libvirt/qemu. I have added the
section:
>
> <serial type="file">
> <source path="/var/log/vm/vml.log"/>
> <target port="0"/>
> </serial>
>
> into the /devices section.
>
> That is I want the stdio to be streamed into the file /var/log/vm/vml.log at the
host.
>
> Then I run simple textual commands at the guest (ls, pwd and so on).
How are you getting into your guest to run those commands? Did you
connect to your guest's serial console, or is it in a gui window, or via
an ssh session, or...? Are you sure the commands you are executing have
the guest's /dev/ttyS0 as their stdout?
Your xml is correct and I think Eric's suggestion is right: if I put
that <serial> snippet into a guest's XML and then echo "foo" >
/dev/ttyS0 in the guest, I see "foo" in the host vml.log.
> But I do not see /var/log/vm/vml.log created at the host.
I'm not sure whether libvirt will pre-create the file, or whether it
insists that the file already exists. Maybe others can chime in. I know
Dave Allan has done some work with python scripts that faithfully
capture all text output to the guest's serial console, although I don't
have a handy link to that sample script.
The example script is consolecallback.py[1] but it really deals more
with auto connecting to a serial console when a VM is booted than with
doing anything special with the output, although it's useful if you
have a VM going up and down and you want all its console output.
Dave
[1]
http://libvirt.org/git/?p=libvirt-python.git;a=blob;f=examples/consolecal...
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
9:52 a.m.
New subject: [libvirt-users] rebooting guests
Dear Friends,
Thanks for your suggestions. I have implemented them; all works!
Now the security module at the hypervisor (KVM) analyzed the data coming from guest and
decided that this guest malfunctions and must be rebooted. When rebooting I address the VM
being rebooted by its name: first getting the domain by name (virDomainLookupByName) and
then reboot the domain (virDomainReset).
The problem is: how can I get the VM name, having the malfunctioning VCPU (struct
kvm_vcpu) as the context ?
I retrieve VCPUs using the following loop:
raw_spin_lock(vm_lock);
list_for_each_entry(kvm, vms_list, vm_list)
{
for (i = 0; i < kvm->online_vcpus.counter; i++)
{
...
}
}
raw_spin_unlock(vm_lock);
Thanks in advance,
Alex BInun
On Wed 28 May 21:44 2014 Dave Allan wrote:
On Wed, May 28, 2014 at 11:28:19AM -0600, Eric Blake wrote:
> On 05/28/2014 09:14 AM, Alexander Binun wrote:
>
> [can you convince your mailer to wrap long lines?]
>
> >
> > I have a program running on a VM guest. Its output is valuable (for VM
introspection) so I want to let the host module know about it. I prefer to redirect '
stdio" of a guest into a device at the host (a text file or my device that has the
name "mydev"
> > and the driver is written for it).
> >
> > I have the XML definition file for my VM in /etc/libvirt/qemu. I have added the
section:
> >
> > <serial type="file">
> > <source path="/var/log/vm/vml.log"/>
> > <target port="0"/>
> > </serial>
> >
> > into the /devices section.
> >
> > That is I want the stdio to be streamed into the file /var/log/vm/vml.log at
the host.
> >
> > Then I run simple textual commands at the guest (ls, pwd and so on).
>
> How are you getting into your guest to run those commands? Did you
> connect to your guest's serial console, or is it in a gui window, or via
> an ssh session, or...? Are you sure the commands you are executing have
> the guest's /dev/ttyS0 as their stdout?
Your xml is correct and I think Eric's suggestion is right: if I put
that <serial> snippet into a guest's XML and then echo "foo" >
/dev/ttyS0 in the guest, I see "foo" in the host vml.log.
> > But I do not see /var/log/vm/vml.log created at the host.
>
> I'm not sure whether libvirt will pre-create the file, or whether it
> insists that the file already exists. Maybe others can chime in. I know
> Dave Allan has done some work with python scripts that faithfully
> capture all text output to the guest's serial console, although I don't
> have a handy link to that sample script.
The example script is consolecallback.py[1] but it really deals more
with auto connecting to a serial console when a VM is booted than with
doing anything special with the output, although it's useful if you
have a VM going up and down and you want all its console output.
Dave
[1]
http://libvirt.org/git/?p=libvirt-python.git;a=blob;f=examples/consolecal...
> --
> Eric Blake eblake redhat com +1-919-301-3266
> Libvirt virtualization library http://libvirt.org
>
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days inactive
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3 comments
3 participants
participants (3)
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Alexander Binun -
Dave Allan -
Eric Blake