Bug 974888

Summary:	Why virtual guest is migrated when the virtual host move to maintenance mode ?
Product:	Red Hat Enterprise Virtualization Manager	Reporter:	Yoshinori Takahashi <hkim>
Component:	Documentation	Assignee:	Tim Hildred <thildred>
Status:	CLOSED NOTABUG	QA Contact:	ecs-bugs
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	3.1.0	CC:	acathrow, dyasny, yeylon
Target Milestone:	---
Target Release:	---
Hardware:	x86_64
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2013-06-18 01:47:30 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:

Comment 1 Tim Hildred 2013-06-18 01:47:30 UTC

Hello Yoshinori-san,

From my understanding, virtual machines have to migrate from a host in maintenance mode, even though you've selected "do not migrate" as your policy.

The alternative is just having running virtual machines die, or not being able to put into maintenance mode any hosts in a cluster with "do not migrate" policy set. When a host unexpectedly shuts down, virtual machines are again on another host depending on your policy. 

"Do not migrate" means that virtual machine will not migrate in case of excessive load on a specific host. 

For a virtual machine to not migrate at all, you want to pin it to a host CPU. That means it needs a specific CPU and will not start on a different host if the host it is pinned to dies unexpectedly. 

Check out "CPU Pinning Topology" in this section:
https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Virtualization/3.2/html-single/Administration_Guide/index.html#sect-Explanation_of_Settings_and_Controls_in_the_New_Virtual_Machine_and_Edit_Virtual_Machine_Windows