Bug 526913

Summary:	QEMU driver does not lock disk files
Product:	[Community] Virtualization Tools	Reporter:	jbrackinshaw
Component:	libvirt	Assignee:	Libvirt Maintainers <libvirt-maint>
Status:	CLOSED CURRENTRELEASE	QA Contact:
Severity:	high	Docs Contact:
Priority:	low
Version:	unspecified	CC:	berrange, crobinso, jtomko, mbooth, xen-maint
Target Milestone:	---
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2015-03-16 14:36:11 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description jbrackinshaw 2009-10-02 13:40:21 UTC

libvirt will not prevent two hosts running the same guest.

Situation:
1. You have a guest on node1
2. You migrate the guest to node2
3. The status according to virsh is:
 node1:guest shut off
 node2:guest running

So here "guest" refers to the same virtual machine, same disk file.

4. You wonder what would happen if a user tried to power on the guest on node1.

root@node2: virtsh start guest

5. It works :(

No warning, no error, no critical error. Just silent data corruption :(

Comment 1 jbrackinshaw 2009-10-05 08:13:21 UTC

libirt 0.6.3-20.

Comment 2 Ján Tomko 2015-03-16 14:36:11 UTC

Libvirt has supported disk locking for a while now, see:
http://libvirt.org/locking.html