Bug 1506260

Summary: [Docs][RFE][Admin] Document Sending an Non-Maskable Interrupt (NMI) to a non-responsive guest
Product: Red Hat Enterprise Virtualization Manager Reporter: Emma Heftman <eheftman>
Component: DocumentationAssignee: Steve Goodman <sgoodman>
Status: CLOSED CURRENTRELEASE QA Contact: Emma Heftman <eheftman>
Severity: medium Docs Contact:
Priority: medium    
Version: 4.2.0CC: eheftman, lbopf, lsurette, pkovar, sgoodman, sgratch, srevivo, vyerys
Target Milestone: ovirt-4.2.6Keywords: FutureFeature, Triaged
Target Release: 4.2.6   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: docs-accepted
Fixed In Version: Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2018-09-04 09:39:00 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: Docs RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 1297037    
Bug Blocks:    

Description Emma Heftman 2017-10-25 13:57:42 UTC
Previously, it was not possible to send an non-maskable interrupt (NMI) to a non-responsive guest operating system.

In this release, users can send  an NMI via the Cockpit. A new menu option called "Send Non-Maskable Interrupt" was added to the "Shut Down" menu that is available from the Virtual Machines tab. It sends a 'virsh inject-nmi' command to the required virtual machine, and it is sent regardless of the virtual machine's state and without checking the type of operating system or its settings.

In the event of an operation system that is not installed or configured correctly, no action will be taken.

More info:
This feature can be used with any OS and any configuration. 
The only must requirement is that an OS should be installed because a VM without OS will remain unresponsive for NMI.
We can just mention that in case of Linux OS, we suggest to configure the OS to handle/not ignore the non-maskable interrupt (because otherwise there is no meaning for sending it and the VM will remain unresponsive) and this can be done by:
1. setting those 2 kernel properties to "1" - for switching the OS to panic mode in case of receiving a NMI.
2. By enabling the kdump service - for creating crash dumps in case of switching to panic mode:
service kdump start

But the user can choose to handle this NMI however he likes.

> 2. What would be the symptom of the VM being non-responsive that would lead
> someone to use this feature?

A non responsive VM is a VM that can't be reached by libvirt and specifically that shutdown/restart/destroy are not working for him.

Comment 11 Emma Heftman 2018-09-03 13:18:17 UTC
Verified.

Comment 12 Steve Goodman 2018-09-04 09:39:00 UTC
This is now published as a Knowledgebase article.

The URL is: https://access.redhat.com/articles/3587631