More details on the subject:

I suppose it is a nested KVM issue because it raised after I enabled the nested KVM feature. Without it, anyway, the second level VMs are unusable in terms of performance.

I am using CentOS 7 with:

kernel: 3.10.0-327.22.2.el7.x86_64
qemu-kvm:1.5.3-105.el7_2.4
libvirt:1.2.17-13.el7_2.5

on both the baremetal and the compute VM.

The only workaround now is to shutdown the compute VM and start it back from baremetal with virsh start.
A simple restart of the compute node doesn't help. It looks like the qemu-kvm process corresponding to the compute VM is the problem.

Laurentiu

În dum., 14 aug. 2016 la 00:19, Laurentiu Soica <laurentiu@soica.ro> a scris:
Hello,

I have an OpenStack setup in virtual environment on CentOS 7.

The baremetal has nested KVM enabled and 1 compute node as a VM.

Inside the compute node I have multiple VMs running.

After about every 3 days the VMs get inaccessible and the compute node reports high CPU usage. The qemu-kvm process for each VM inside the compute node reports full CPU usage.

Please help me with some hints to debug this issue.

Thanks,
Laurentiu