Hi Kashyap, Thanks for the reply.
Now for some reason, I need to add “ -qmp tcp:127.0.0.1:1235” when creating a KVM VM using libvirt.
You might need to elaborate how exactly you're doing this.
I wanted to add “-qmp tcp:127.0.0.1:1235” when creating VM because I was using a multi-level debugger which needs this option to get more information of the VM kernel debuginfo and the processes running inside the VM besides gdb attach.
This command meaning in “qemu-kvm --help” is: -qmp dev like -monitor but opens in 'control' mode.
The above is used if you want to explicitly control a running QEMU instance via QMP, e.g. manually issue them QMP commands via telnet(1) for development/testing/debugging.
This is exactly what I need - for debugging. Is there a way to achieve this while still using the default monitor libvirt provides?
I added command-line equivalent options into the xml file, like below format:
<qemu:commandline> <qemu:arg value="-s"/> <qemu:arg value="-qmp"/> <qemu:arg value="tcp:127.0.0.1:1235"/> </qemu:commandline>
In guests created in a regular fashion (e.g. virt-install, virt-manager), this is all handled by libvirt for you via its APIs.
However when I create VM using this xml file, I got the error:
# virsh create instance-libvirt.xml error: Failed to create domain from instance-libvirt.xml error: internal error process exited while connecting to monitor: qemu-kvm: -qmp tcp:127.0.0.1:1235: Duplicate ID 'monitor' for mon duplicate chardev: monitor
The VM I created, without “—qmp” option, has below options showing in “ps aux | grep qemu-kvm”:
-chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/vmifs_test.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control
Looks like libvirt automatically adds the monitor options upon VM creation.
As I understand it, libvirt uses its own APIs to handle interactions with QEMU monitor console, e.g. qemuMonitorOpen(), etc.
If you're fine delving into code, you might want to libvirt sources, specificially this directory: libvirt/src/qemu.
Messing up the source code is the last thing I want to do. I am using the default libvirt coming with CentOs6.5, last time I modified and installed the libvirt source code, I got seriously version-not-match problem.
Is there a way to disable this and use “—qmp” instead when creating VM?
I doubt libvirt developers will agree with this proposal. But if you're intending to try QEMU monitor console for testing, here's some old notes on different ways to access QEMU monitor via QMP:
http://kashyapc.com/2013/03/31/multiple-ways-to-access-qemu-monitor-protocol...
I’ve read this and looks like you’re also using command line to create a KVM machine while enabling “—qmp” option. Is there a way to do this but still creating VM through libvirt? Thank you very much for your time! Best Regards, Min On Nov 9, 2014, at 11:34 AM, Kashyap Chamarthy <kchamart@redhat.com> wrote:
On Fri, Nov 07, 2014 at 03:28:57PM -0700, Min Du wrote:
Hi,
Now for some reason, I need to add “ -qmp tcp:127.0.0.1:1235” when creating a KVM VM using libvirt.
You might need to elaborate how exactly you're doing this.
This command meaning in “qemu-kvm --help” is: -qmp dev like -monitor but opens in 'control' mode.
The above is used if you want to explicitly control a running QEMU instance via QMP, e.g. manually issue them QMP commands via telnet(1) for development/testing/debugging.
I added command-line equivalent options into the xml file, like below format:
<qemu:commandline> <qemu:arg value="-s"/> <qemu:arg value="-qmp"/> <qemu:arg value="tcp:127.0.0.1:1235"/> </qemu:commandline>
In guests created in a regular fashion (e.g. virt-install, virt-manager), this is all handled by libvirt for you via its APIs.
However when I create VM using this xml file, I got the error:
# virsh create instance-libvirt.xml error: Failed to create domain from instance-libvirt.xml error: internal error process exited while connecting to monitor: qemu-kvm: -qmp tcp:127.0.0.1:1235: Duplicate ID 'monitor' for mon duplicate chardev: monitor
The VM I created, without “—qmp” option, has below options showing in “ps aux | grep qemu-kvm”:
-chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/vmifs_test.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control
Looks like libvirt automatically adds the monitor options upon VM creation.
As I understand it, libvirt uses its own APIs to handle interactions with QEMU monitor console, e.g. qemuMonitorOpen(), etc.
If you're fine delving into code, you might want to libvirt sources, specificially this directory: libvirt/src/qemu.
Is there a way to disable this and use “—qmp” instead when creating VM?
I doubt libvirt developers will agree with this proposal. But if you're intending to try QEMU monitor console for testing, here's some old notes on different ways to access QEMU monitor via QMP:
http://kashyapc.com/2013/03/31/multiple-ways-to-access-qemu-monitor-protocol...
-- /kashyap