Bug 1303624

Summary:	[Alcatel vRAN Project] Provide a mechanism to hotplug memory in non-numa guests
Product:	Red Hat Enterprise Linux 7	Reporter:	Ahmed El-Khouly <ahmed.el-khouly>
Component:	libvirt	Assignee:	Libvirt Maintainers <libvirt-maint>
Status:	CLOSED WONTFIX	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	7.3	CC:	pkrempa, rbalakri
Target Milestone:	rc
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2016-02-01 14:04:05 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Ahmed El-Khouly 2016-02-01 13:53:33 UTC

Description of problem:
It seems that libvirt only support hotplug of memory for guests that exhibit NUMA topology. The only way to hot plug/unplug memory is using the balloon driver which is not a safe mechanism for cloud environments as guests may not be cooperating or even malicious.


Version-Release number of selected component (if applicable):


How reproducible:


Steps to Reproduce:
1. Set MaxMemory element in XML.
2. Boot Instance
3. Boot fails with libvirt error.

Actual results:


Expected results:


Additional info:

Comment 2 Peter Krempa 2016-02-01 14:04:05 UTC

For x86, qemu mandates the use of a NUMA node to maintain compatibility with windows guests. As the NUMA node is added by qemu, we have to enforce it so that the XML matches the expected config.

A workaround is to add 1 NUMA node to the domain XML, which will be equivalent to the normal configuration.

For non-x86 guests, use of NUMA is not mandated.