Bug 2125290

Summary:	LVM devices file is not created if the hypervisor is installed without LVM
Product:	Red Hat Enterprise Virtualization Manager	Reporter:	Juan Orti <jortialc>
Component:	vdsm	Assignee:	Albert Esteve <aesteve>
Status:	CLOSED NEXTRELEASE	QA Contact:	Shir Fishbain <sfishbai>
Severity:	medium	Docs Contact:
Priority:	unspecified
Version:	4.5.1	CC:	ahadas, emarcus, lsurette, mavital, mperina, srevivo, ycui
Target Milestone:	ovirt-4.5.3
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	vdsm-4.50.3.3	Doc Type:	Bug Fix
Doc Text:	Previously, an LVM device file was not created if no LVM devices were found during VDSM configuration. As a result, all LVM commands worked on VGs belonging to RHV storage domains. In this release, the vdsm-tool creates a devices file even when no LVM devices are found, and Storage Domain VGs are not seen by LVM commands.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2022-10-17 15:00:38 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	Storage	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Juan Orti 2022-09-08 14:12:50 UTC

Description of problem:
If a RHEL hypervisor is installed directly on partitions without LVM, then the LVM devices file '/etc/lvm/devices/system.devices' is not created when the host is added to a cluster.
The missing LVM devices file causes that all LVM commands work on VGs belonging to RHV storage domains with the risk associated.

Version-Release number of selected component (if applicable):
ovirt-engine-4.5.1.3-0.28.el8ev.noarch
vdsm-4.50.1.4-1.el8ev.x86_64

How reproducible:
Always

Steps to Reproduce:
1. Install a RHEL 8.6 hypervisor without LVM:

~~~
# lsblk 
NAME                                                  MAJ:MIN RM  SIZE RO TYPE  MOUNTPOINT
vda                                                   252:0    0   70G  0 disk  
├─vda1                                                252:1    0    1M  0 part  
├─vda2                                                252:2    0  100M  0 part  /boot/efi
└─vda3                                                252:3    0 69,9G  0 part  /
~~~

2. Add the host to a cluster that has some block-based storage domains

Actual results:
- No LVM devices file '/etc/lvm/devices/system.devices' is created.
- Any LVM command can see the storage domains VGs:

~~~
# lvs
  LV                                   VG                                   Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  3a3e7624-fc68-49fe-ae5d-b14716e8fe20 fe2907d5-7dfb-4b1c-883c-a75d937c73ed -wi------- 128,00m                                                    
  d47878c2-f542-4739-b6c2-b490e9a1a301 fe2907d5-7dfb-4b1c-883c-a75d937c73ed -wi------- 128,00m                                                    
  ids                                  fe2907d5-7dfb-4b1c-883c-a75d937c73ed -wi-ao---- 128,00m                                                    
  inbox                                fe2907d5-7dfb-4b1c-883c-a75d937c73ed -wi-a----- 128,00m                                                    
  leases                               fe2907d5-7dfb-4b1c-883c-a75d937c73ed -wi-a-----   2,00g                                                    
  master                               fe2907d5-7dfb-4b1c-883c-a75d937c73ed -wi-a-----   1,00g                                                    
  metadata                             fe2907d5-7dfb-4b1c-883c-a75d937c73ed -wi-a----- 128,00m                                                    
  outbox                               fe2907d5-7dfb-4b1c-883c-a75d937c73ed -wi-a----- 128,00m                                                    
  xleases                              fe2907d5-7dfb-4b1c-883c-a75d937c73ed -wi-a-----   1,00g    
~~~

Expected results:
We need to create a LVM devices file with no devices.
I've tested that creating the file '/etc/lvm/devices/system.devices' with only the VERSION variable works as expected:

~~~
VERSION=1.1.1
~~~

Additional info:

Comment 2 Casper (RHV QE bot) 2022-09-08 14:31:02 UTC

This bug has low overall severity and is not going to be further verified by QE. If you believe special care is required, feel free to properly align relevant severity, flags and keywords to raise PM_Score or use one of the Bumps ('PrioBumpField', 'PrioBumpGSS', 'PrioBumpPM', 'PrioBumpQA') in Keywords to raise it's PM_Score above verification threashold (1000).

Comment 3 Juan Orti 2022-09-27 09:13:11 UTC

Hi, I've confirmed that having VERSION in the file is not needed. Creating an empty '/etc/lvm/devices/system.devices' file is enough.

Comment 8 Casper (RHV QE bot) 2022-10-17 15:00:38 UTC

This bug has low overall severity and passed an automated regression suite, and is not going to be further verified by QE. If you believe special care is required, feel free to re-open to ON_QA status.