1335617 – print generic error to user if qemu fails without printing any error

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Bug 1335617 - print generic error to user if qemu fails without printing any error

Summary: print generic error to user if qemu fails without printing any error

Keywords:
Status:	CLOSED ERRATA
Alias:	None
Product:	Red Hat Enterprise Linux 7
Classification:	Red Hat
Component:	libvirt
Sub Component:
Version:	7.3
Hardware:	Unspecified
OS:	Unspecified
Priority:	unspecified
Severity:	unspecified
Target Milestone:	rc
Target Release:	---
Assignee:	Pavel Hrdina
QA Contact:	Virtualization Bugs
Docs Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+	depends on / blocked

Reported:	2016-05-12 16:25 UTC by David Jaša
Modified:	2016-11-03 18:45 UTC (History)
CC List:	8 users (show)
Fixed In Version:	libvirt-2.0.0-1.el7
Doc Type:	Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed:	2016-11-03 18:45:10 UTC
Target Upstream Version:
Embargoed:

Attachments	(Terms of Use)

Links
System	ID	Private	Priority	Status	Summary	Last Updated
Red Hat Product Errata	RHSA-2016:2577	0	normal	SHIPPED_LIVE	Moderate: libvirt security, bug fix, and enhancement update	2016-11-03 12:07:06 UTC

Description David Jaša 2016-05-12 16:25:37 UTC

Description of problem:
bug 1328898 comment 19 is a good example of unhelpful error reporting by virt-manager - instead of providing full error by libvirt when starting domain, virt-manager truncates this useful output and print irrelevant python trackebacks instead. A good reproducer for this can be attempt to start domain with nfs-backed disk with virt_use_nfs SELinux boolean set to off.

Version-Release number of selected component (if applicable):
virt-manager-1.3.2-1.el7.noarch

How reproducible:
always

Steps to Reproduce:
1. make VM unstartable, e.g. by using file on nfs to back it's disk and set 'virt_use_nfs' SELinux boolean to off
2. start domain in virt-manager
3.

Actual results:
virt-manager produces unintelligible python traceback (for people not familiar with virt-manager/python/qemu stack)

Expected results:
virt-manager says that VM failed to start because of error in uderlying layers and it should print at least the same error as 'virsh start $DOMAIN' would

Additional info:

Comment 1 Pavel Hrdina 2016-05-26 10:22:21 UTC

Virt-manager prints exactly what it receive from libvirt, we don't truncate anything.  There is only a bug in libvirt, in case that qemu fails without any error we will print qemu command line instead of same sane error message.

Comment 2 Pavel Hrdina 2016-05-30 07:35:27 UTC

So after some testing I've found out that we for a long time doesn't print command line to user if qemu fails without any error.

If there is no error we prints only the libvirt part without any explanation:

"error: internal error: process exited while connecting to monitor:"

The only fix that should improve the error message is in this case to print some generic error explaining what happened.

Comment 3 Pavel Hrdina 2016-06-08 11:58:00 UTC

Upstream commit:

commit 407c6909bc887d77b2c8617fbe6b542d48afec5b
Author: Pavel Hrdina <phrdina>
Date:   Wed Jun 8 12:03:38 2016 +0200

    qemu_process: don't print empty line if qemu exits without any error

Comment 5 lijuan men 2016-07-18 09:00:52 UTC

verify the bug

version:
libvirt-2.0.0-2.el7.x86_64
qemu-kvm-rhev-2.6.0-13.el7.x86_64
kernel-3.10.0-470.el7.x86_64

steps:
1.prepare a guest with nfs disk
2.set virt_use_nfs as off
[root@localhost ~]# setsebool virt_use_nfs off
3.start the guest
[root@localhost ~]# virsh start bios
error: Failed to start domain bios
error: internal error: qemu unexpectedly closed the monitor: 2016-07-18T07:45:34.842844Z qemu-kvm: -drive file=/opt/test/admin.qcow2,format=qcow2,if=none,id=drive-ide0-0-0: Could not open '/opt/test/admin.qcow2': Permission denied
4.use virt-manager to start the guest
the error info is the same as step 3

Comment 7 errata-xmlrpc 2016-11-03 18:45:10 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.

https://rhn.redhat.com/errata/RHSA-2016-2577.html

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