Bug 1850920

Summary:	Live snapshot made with freeze in the engine will cause the FS to be frozen [RHV clone - 4.3.11]
Product:	Red Hat Enterprise Virtualization Manager	Reporter:	RHV bug bot <rhv-bugzilla-bot>
Component:	ovirt-engine	Assignee:	Liran Rotenberg <lrotenbe>
Status:	CLOSED ERRATA	QA Contact:	Qin Yuan <qiyuan>
Severity:	unspecified	Docs Contact:
Priority:	high
Version:	4.3.10	CC:	bpelled, bugs, cshao, emarcus, mkalinin, pelauter, rdlugyhe
Target Milestone:	ovirt-4.3.11	Keywords:	ZStream
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:	Previously, creating a live snapshot with memory while LiveSnapshotPerformFreezeInEngine was set to True resulted in a virtual machine file system that is frozen when previewing or committing the snapshot with memory restore. In this release, the virtual machine runs successfully after creating a preview snapshot from a memory snapshot.	Story Points:	---
Clone Of:	1838493	Environment:
Last Closed:	2020-09-30 10:07:13 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	Virt	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1838493
Bug Blocks:

Description RHV bug bot 2020-06-25 07:48:45 UTC

+++ This bug is a downstream clone. The original bug is: +++
+++   bug 1838493 +++
======================================================================

Description of problem:
Creating a live snapshot with memory and having LiveSnapshotPerformFreezeInEngine set to true will result in VM that has the file system frozen upon previewing or commiting.

Version-Release number of selected component (if applicable):
4.3.10

How reproducible:
100%

Steps to Reproduce:
1. Set the LiveSnapshotPerformFreezeInEngine=true in engine config.
2. Create a VM with disk.
3. Create snapshot with memory.
4. Shutdown the VM.
5. Preview or preview+commit the snapshot with memory restore.
6. Start the VM.

Actual results:
The VM's file system will be frozen.

Expected results:
The VM should be restored without being frozen.


Additional info:
Workarounds:
1. Change the config of LiveSnapshotPerformFreezeInEngine to false.
2. Shutting down the VM and starting it again.
3. Doing preview, starting the VM(it will be frozen), shutting it down, commiting the snapshot and start.
4. Running: # vdsm-client VM thaw vmID=<uuid> on the host the VM is running and the FS is frozen.
5. Create the snapshot without memory.

(Originally by Liran Rotenberg)

Comment 2 RHV bug bot 2020-06-25 07:48:49 UTC

We shouldn't call freeze or thaw when doing live snapshot with memory(the VM is paused during it - makes sure of data consistency).
In this scenario when restoring it with memory the FS will be frozen and we can't do anything.
The freeze/thaw calls should happen only when creating non-memory live snapshot in order to make the data consistent.

(Originally by Liran Rotenberg)

Comment 4 RHV bug bot 2020-06-25 07:48:53 UTC

Sure, we still have time. Not so much a backport as just changing the milestone to whichever (4.4.1 or 4.4.2) fits once it merges

(Originally by rbarry)

Comment 7 RHV bug bot 2020-06-25 07:48:59 UTC

Verified with:
ovirt-engine-4.3.11-0.1.el7.noarch

Steps:
1. Set the LiveSnapshotPerformFreezeInEngine=true in engine config
2. Create a VM with disk.
3. Create snapshot with memory.
4. Shutdown the VM.
5. Preview+commit the snapshot with memory restore.
6. Start the VM.

Result:
1. The VM is restored without being frozen.

(Originally by Qin Yuan)

Comment 8 Liran Rotenberg 2020-06-25 07:54:30 UTC

Moving to verified based on the last comment.

Comment 13 errata-xmlrpc 2020-09-30 10:07:13 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 (Red Hat Virtualization Engine security, bug fix 4.3.11), and where to find the updated
files, follow the link below.

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

https://access.redhat.com/errata/RHBA-2020:4112