[CentOS-virt] Problem loading the VM after reboots.

Sat Feb 25 20:19:39 UTC 2017
Subscriber <ml-lists at agoris.net.ua>

I had a strange problem. After restarting the VM can not always run.
The last line in the console (virsh console):

init: Re-executing /sbin/init
Please stand by while rebooting the system...
Restarting system.
machine restart

At this time, one of the CPU core is loaded 100% (qemu-kvm process,
top command)

%Cpu7  : 41.8 us, 57.6 sy,  0.0 ni,  0.6 id,  0.0 wa,  0.0 hi,  0.0
si,  0.0 st

# free
              total        used        free      shared  buff/cache  
available
Mem:        8009692      377744     1164076        9392     6467872  
7299800
Swap:       2097148           0     2097148

This behavior only when the virtual machine CentOS 6.8 and HV CentOS
7.3.1116. Unsuccessful restart may occur after 2 successful, and maybe
after 5 successful, and maybe on the first reboot. No clear pattern of
a problem I have not seen. Tested different VM.

Here's how behaved virtual machine if its reboot through virsh reboot:

virsh # reboot test1
Domain test1 is being rebooted
virsh # reboot test1
Domain test1 is being rebooted
virsh # destroy test1
Domain test1 destroyed
virsh # start test1
Domain test1 started
virsh # reboot test1
Domain test1 is being rebooted
virsh # reboot test1
Domain test1 is being rebooted
virsh # destroy test1
Domain test1 destroyed
virsh # start test1
Domain test1 started
virsh # reboot test1
Domain test1 is being rebooted
virsh # reboot test1
Domain test1 is being rebooted
virsh # reboot test1
Domain test1 is being rebooted
virsh # reboot test1
Domain test1 is being rebooted 
virsh # reboot test1
Domain test1 is being rebooted
virsh # reboot test1
Domain test1 is being rebooted
virsh # reboot test1
Domain test1 is being rebooted
virsh # destroy test1
Domain test1 destroyed

If the VM shutdown and then start, the problem does not occur.
The problem does not occur if the VM CentOS 7.3.1611 (10 successful
reboots of 10) or if the VM Windows Server 2008 R2 (10 successful
reboots of 10).
If the VM CentOS 6.8 and HV CentOS 6.8 the problem does not occur.

First HV is:
CentOS 7.3.1611 with 3.10.0-514.6.2.el7.x86_64 and
3.10.0-514.6.1.el7.x86_64
qemu-kvm-ev.x86_64                    10:2.6.0-28.el7_3.3.1
libvirt.x86_64                        2.0.0-10.el7_3.4

Kernel module: 
kvm_intel             170181
kvm                   554609

Second HV is:
CentOS 7.3.1611 with 3.10.0-514.6.2.el7.x86_64

qemu-kvm.x86_64                        10:1.5.3-126.el7_3.3
libvirt.x86_64                        2.0.0-10.el7_3.4

Kernel module: 
kvm_intel             170181
kvm                   554609