Bug 1303624 - [Alcatel vRAN Project] Provide a mechanism to hotplug memory in non-numa guests
[Alcatel vRAN Project] Provide a mechanism to hotplug memory in non-numa guests
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: libvirt (Show other bugs)
Unspecified Unspecified
unspecified Severity unspecified
: rc
: ---
Assigned To: Libvirt Maintainers
Virtualization Bugs
Depends On:
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Reported: 2016-02-01 08:53 EST by Ahmed El-Khouly
Modified: 2016-02-01 09:04 EST (History)
2 users (show)

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Fixed In Version:
Doc Type: Bug Fix
Doc Text:
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Last Closed: 2016-02-01 09:04:05 EST
Type: Bug
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RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

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Description Ahmed El-Khouly 2016-02-01 08:53:33 EST
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 09:04:05 EST
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.

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