[libvirt] Disconnected from qemu, keepalive timeout

[Nir Levy]

Thanks you,

Yes, indeed after virsh start.
That's will surely help.

I am really struggling to understand how eventually the libvirt is managing the qemu via its fd's
I can see that virsh is launching qemu right after:
execve(binary, cmd->args, cmd->env);

I have grasp too that libvirtd is communicate with the qemu through.
virCgroupSetValueStr (group=0x7fb87400cd10, controller=0, key=0x7fb8b4377bbb "tasks", value=0x7fb874008170 "6909") at util/vircgroup.c:751
5: value = 0x7fb874008170 "6909"
1: keypath = 0x7fb87400ecd0 "/sys/fs/cgroup/cpu,cpuacct/machine/VBS2.libvirt-qemu/vcpu0/tasks"

Where value is the thread running the VCPU.
Thread 0x7fa684833700 (LWP 6909) "qemu-system-x86" pthread_cond_wait@@GLIBC_2.3.2 ()

Another example is setting the env parameter.
virCgroupSetValueStr (group=0x7fb87400cd10, controller=2, key=0x7fb8b43779eb "cpuset.cpus", value=0x7fb874010dd0 "0-15") at util/vircgroup.c:751
5: value = 0x7fb874010dd0 "0-15"
1: keypath = 0x7fb87400ecd0 "/sys/fs/cgroup/cpuset/machine/VBS2.libvirt-qemu/vcpu0/cpuset.cpus"

I have failed to get Cgroup idea 
And to actually see my event being traced.

Thanks for your quick response.
Very appreciated.

Regards,
Nir

-----Original Message-----
From: Martin Kletzander [mailto:mkletzan at redhat.com] 
Sent: Thursday, July 14, 2016 9:00 AM
To: Nir Levy <nirl at asocsnetworks.com>
Cc: libvir-list at redhat.com; veillard at redhat.com
Subject: Re: [libvirt] Disconnected from qemu, keepalive timeout

On Wed, Jul 13, 2016 at 03:47:37PM +0000, Nir Levy wrote:
>Hello Guys,
>
>Thanks for reading this,
>I have compiled libvirt and qemu over fedora 22 for using debug information and no opt ("-g3 -O0").
>I am investigating the xml feature
>  <qemu:commandline>
>    <qemu:arg value='-trace'/>
>    <qemu:arg value='events=/home/qemu_traced_symbols'/>
>  </qemu:commandline>
>
>qemu_traced_symbols includes all qemu traced symbols.
>
>I have used:
>catch syscall clone
>set follow-fork-mode child
>set detach-on-fork off
>
>and debugged the child
>so after libvirt start VM2 wanted to debug the parameters (cmd->args, 
>which indeed includes -trace and  events=/home/qemu_traced_symbols I have debugged the the child after spawning.
>And returned for the parent (using gdb inferior 1) for debugging the 
>virCommandHandshakeWait (with the args)
>
>but I keep getting
>error: Disconnected from qemu:///system due to keepalive timeout grep @ 
>libvirt-1.2.21/ shows no code only change log.
>

You are getting this from the 'virsh start $domain' command, right?

>Can you please help me resolve this issue?
>How do those args are passed, is it via JSON?
>

For your use case you really want to disable the keepalive by using -k0 parameter for virsh, so it will become 'virsh -k0 start $domain'

>Kind regards,
>Nir Levy
>SW Engineer
>
>Web: www.asocstech.com<http://www.asocstech.com/> | 
>[cid:image001.jpg at 01D1B599.5A2C9530]
>



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