Bug 697650

Summary:	on disk xml should warn that it is autogenerated
Product:	Red Hat Enterprise Linux 6	Reporter:	Dave Allan <dallan>
Component:	libvirt	Assignee:	Michal Privoznik <mprivozn>
Status:	CLOSED ERRATA	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	high	Docs Contact:
Priority:	high
Version:	6.2	CC:	dyuan, eblake, gren, mzhan, rwu, yoyzhang
Target Milestone:	rc
Target Release:	---
Hardware:	All
OS:	All
Whiteboard:
Fixed In Version:	libvirt-0.9.2-1.el6	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2011-12-06 11:05:15 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:

Description Dave Allan 2011-04-18 20:20:20 UTC

Description of problem:
Users often mistakenly edit on disk xml for qemu domains thinking that it's a safe way to modify a domain.  The on disk xml should contain a comment stating:

"WARNING: THIS IS AN AUTO-GENERATED FILE.  CHANGES TO IT ARE LIKELY TO BE OVERWRITTEN AND LOST.  Changes to xml configurations should be made using virsh edit or other application using the libvirt API.  See:

http://wiki.libvirt.org/wiki/index.php?title=FAQ#Where_are_VM_config_files_stored.3F_How_do_I_edit_a_VM.27s_XML_config.3F"

The lack of understanding of this situation leads to user confusion and support requests.

Comment 1 Dave Allan 2011-04-27 17:48:35 UTC

Raising the severity and priority to high to reflect widespread confusion on this issue.

Comment 2 Michal Privoznik 2011-04-28 16:36:13 UTC

Patch sent upstream:

https://www.redhat.com/archives/libvir-list/2011-April/msg01225.html

Comment 3 Michal Privoznik 2011-05-09 19:36:07 UTC

pushed upstream:

commit 5d09c314952b23a303aa40a0d7b9854dd0ae86dd
Author: Michal Privoznik <mprivozn>
Date:   Fri Apr 29 11:28:28 2011 +0200

    Add warning message to XML definition files stored on disk
    
    Users often edit XML file stored in configuration directory
    thinking of modifying a domain/network/pool/etc. Thus it is wise
    to let them know they are using the wrong way and give them hint.

v0.9.1-16-g5d09c31

Comment 5 Daniel Veillard 2011-06-23 03:09:28 UTC

This should be fixed by the libvirt-0.9.2-1.el6 rebase

Comment 6 zhanghaiyan 2011-06-23 06:33:41 UTC

Verified this bug pass with libvirt-0.9.2-1.el6.x86_64
- 2.6.32-156.el6.x86_64
- qemu-kvm-0.12.1.2-2.165.el6.x86_64

# vi /etc/libvirt/qemu/rhel61.xml
<!--
WARNING: THIS IS AN AUTO-GENERATED FILE. CHANGES TO IT ARE LIKELY TO BE
OVERWRITTEN AND LOST. Changes to this xml configuration should be made using:
  virsh edit rhel61
or other application using the libvirt API.
-->

<domain type='kvm'>
  <name>rhel61</name>
  <uuid>e3d2704d-35c7-1f8b-c762-cc4ade35f12a</uuid>
  <memory>1048576</memory>
  <currentMemory>1048576</currentMemory>
  <vcpu>2</vcpu>
  <os>
    <type arch='x86_64' machine='rhel6.1.0'>hvm</type>
    <boot dev='hd'/>
  </os>
.......

If you still do some changes on this xml, for example, changing vcpu from 2 to 1, you will find it doesn't work at all. The guest still has 2 vcpus, the same after you restart the guest. This is expected as said in the warning 'CHANGES TO IT ARE LIKELY TO BE OVERWRITTEN AND LOST'

Comment 8 Rita Wu 2011-07-06 10:54:49 UTC

Set it as VERIFIED per comment 6

Comment 9 errata-xmlrpc 2011-12-06 11:05:15 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHBA-2011-1513.html