[Qemu-devel] Question on QEMU : How to record debug log in VM of QEMU

[Qemu-devel] Question on QEMU : How to record debug log in VM of QEMU

[S KH]

This is a question I have encountered while using QEMU.

I want to compile the source directly rather than through apt or yum and
install QEMU and input the output statement to the source to check the
output value.

When I compiled QEMU using dpkg-buildpackage in Ubuntu, I verified that
when QEMU's VM is executed by inputting and compiling the output statement,
the output value is recorded in the log file(ex.
/var/log/libvirt/qemu/win7.log) of that VM.

In Centos, I tried to use rpmbuild to input the output to QEMU source,
compile and check the output value. I confirmed that the log file is not
written, but I have confirmed that the output value is rare from the
terminal during the compilation process.

What I want to do is to get the output to be written to the log file like
in Ubuntu.

Thank you

Re: [Qemu-devel] Question on QEMU : How to record debug log in VM of QEMU

[Stefan Hajnoczi]

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On Tue, May 07, 2019 at 11:29:03AM +0900, S KH wrote:
> This is a question I have encountered while using QEMU.
> 
> I want to compile the source directly rather than through apt or yum and
> install QEMU and input the output statement to the source to check the
> output value.
> 
> When I compiled QEMU using dpkg-buildpackage in Ubuntu, I verified that
> when QEMU's VM is executed by inputting and compiling the output statement,
> the output value is recorded in the log file(ex.
> /var/log/libvirt/qemu/win7.log) of that VM.
> 
> In Centos, I tried to use rpmbuild to input the output to QEMU source,
> compile and check the output value. I confirmed that the log file is not
> written, but I have confirmed that the output value is rare from the
> terminal during the compilation process.
> 
> What I want to do is to get the output to be written to the log file like
> in Ubuntu.

Try diffing /etc/libvirt/qemu.conf between the Ubuntu and CentOS hosts.
Maybe they have different logging setups.  In particular, the
stdio_handler setting might be different.

Stefan

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Re: [Qemu-devel] Question on QEMU : How to record debug log in VM of QEMU

[Daniel P. Berrangé]

On Thu, May 09, 2019 at 02:45:25PM +0100, Stefan Hajnoczi wrote:
> On Tue, May 07, 2019 at 11:29:03AM +0900, S KH wrote:
> > This is a question I have encountered while using QEMU.
> > 
> > I want to compile the source directly rather than through apt or yum and
> > install QEMU and input the output statement to the source to check the
> > output value.
> > 
> > When I compiled QEMU using dpkg-buildpackage in Ubuntu, I verified that
> > when QEMU's VM is executed by inputting and compiling the output statement,
> > the output value is recorded in the log file(ex.
> > /var/log/libvirt/qemu/win7.log) of that VM.
> > 
> > In Centos, I tried to use rpmbuild to input the output to QEMU source,
> > compile and check the output value. I confirmed that the log file is not
> > written, but I have confirmed that the output value is rare from the
> > terminal during the compilation process.
> > 
> > What I want to do is to get the output to be written to the log file like
> > in Ubuntu.
> 
> Try diffing /etc/libvirt/qemu.conf between the Ubuntu and CentOS hosts.
> Maybe they have different logging setups.  In particular, the
> stdio_handler setting might be different.

That shouldn't matter - regardless of which stdio_handler is in use,
the logs end up in the same file, with no buffering added by libvirt.


Regards,
Daniel
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