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