Comment 12 for bug 985489

Description of this problem

I have met this problem before. This bug is mainly caused by libvirt & openstack-compute driver for libvirt.

When you meet this problem. You may type command.

$ virsh list --all

If this command get stucked, you may face this problem. Another interesting appearance is that, if you type

$ ps aux | grep libvirtd

You may find two libvirtd service is running. Such as,

...... /usr/sbin/libvirtd -d
...... /usr/sbin/libvirtd -d

You kill one process, then libvirt will be ok. But sometimes later, the bug will come out again.

Reasons of this problem

Why this bug comes out?
1 This bug mainly caused by libvirt. The older verion of libvirt has multi-process/multi-threads lock bugs. Sometimes, when multi-processes access libvirt/libvirtd services by libvirt-api, this error will happen. Especially, if you access libvirt from differe process or threads, then this bug will come out. All accesses of libvirt will get stucked.

2 The driver of libvirt in OpenStack, access libvirt/libvirtd service too frequently. Especially, when you have a lot of vms running on libvirt.

Solutions for this bug:

1 You have to update you libvirt/libvirtd services. My advice is your libvirt version should > 0.9.13.
2 We may have some methods to get lower frequent of these accesses.

I think I can fix this Bug. ^_^. I have fix it in my env of openstack.