Hypervisor broken
by Hans Scheffers
Hi all,
I am new here, been searching the mailing list on a regular base when
I encountered problems and till now I always was able to keep the
system up & running. As said... till now...
I have oVirt at home, and I have about 7 vm's running on it. Lately I
have had some troubles with my electricity, which results in a
complete power outage on a irregular base. Yesterday I had a power
outage which left the system unbootable with the following errors:
error:
../../grub-core/loader/i386/pc/linux.c:170:invalid magic number.
error: ../../grub-core/loader/i386/pc/linux.c:1418:you need to load
the kernel first.
Press any key to continue
Normally this can be solved following
https://access.redhat.com/solutions/5829141, but his time also the
files in /boot had a size of 0 bytes. So basically i did not have a
working kernel on the system anymore.
https://www.thegeekdiary.com/centos-rhel-7-how-to-install-kernel-from-res...
does work for CentOS 8 also, but the ovirt 4.8 iso does not have the
same directory structure. Using CentOS 8 installs a kernel, but not a
bootable system.
When booting the ovirt kernel, I get a rescue prompt with the
following error: "Warning:
/dev/onn/ovirt-node-ng-4.4.6.3-0.20210518.0+1 does not exist"
Is there a way i can start the installer in troubleshooting mode so I
can do a reinstall and keep the current configuration or can I just
reinstall and import the current datacenter in it?
3 years, 6 months
Hosted Engine cluster version compatib.
by Andrea Chierici
Dear all,
I have just updated my ovirt installation, with self hosted engine, from
4.4.5 to 4.4.8.5-1.
Everything went smoothly and in a few minutes the system was back up and
running.
A little issue is still puzzling me.
I am asked to update from 4.5 to 4.6 the cluster and data center
compatibility level. When I try to issue the command from the cluster
config I get this error:
> Error while executing action: Cannot update cluster because the update
> triggered update of the VMs/Templates and it failed for the following:
> HostedEngine. To fix the issue, please go to each of them, edit,
> change the Custom Compatibility Version (or other fields changed
> previously in the cluster dialog) and press OK. If the save does not
> pass, fix the dialog validation. After successful cluster update, you
> can revert your Custom Compatibility Version change (or other
> changes). If the problem still persists, you may refer to the
> engine.log file for further details.
It's very strange because the config of the hostedengine is "plain" and
there are no constrains on compatibility version, as you can see in this
picture:
In any case, if I try to force compatibility with 4.6 I get this error:
> Error while executing action:
>
> HostedEngine:
>
> There was an attempt to change Hosted Engine VM values that are
> locked.
So I am stuck. Not a big deal at the moment, but sooner or later I will
have to do this upgrade and I don't know where I am wrong.
Can anybody give a clue?
Thanks in advance,
Andrea
--
Andrea Chierici - INFN-CNAF
Viale Berti Pichat 6/2, 40127 BOLOGNA
Office Tel: +39 051 2095463
SkypeID ataruz
--
3 years, 7 months
Ooops! in last step of Hyperconverged deployment
by Harry O
Hi,
In the second engine dep run in Hyperconverged deployment I get red "Ooops!" in cockpit.
I think it fails on some networking setup.
The first oVirt Node says "Hosted Engine is up!" but the other nodes is not added to HostedEngine yet.
There is no network connectivity to the Engine outside node1, I can ssh to engine from node1 on the right IP-address.
Please tell what logs I should pull.
3 years, 7 months
About the vm memory limit
by Tommy Sway
I would like to ask if there is any limit on the memory size of virtual
machines, or performance curve or something like that?
As long as there is memory on the physical machine, the more virtual
machines the better?
In our usage scenario, there are many virtual machines with databases, and
their memory varies greatly.
For some virtual machines, 4G memory is enough, while for some virtual
machines, 64GB memory is needed.
I want to know what is the best use of memory for a virtual machine, since
the virtual machine is just a QEMU emulation process on a physical machine,
and I worry that it is not using as much memory as a physical machine.
Understand this so that we can develop guidelines for optimal memory usage
scenarios for virtual machines.
Thank you!
3 years, 7 months
about the power management of the hosts
by Tommy Sway
Everybody, hi:
I would like to ask, after the configuration of power management on the
host, under what circumstances will work?
That is, when does the engine send a request to the IPMI module to restart
the power supply?
Is it necessary to configure power management modules in the production
environment?
Are there any risks?
Thanks!
3 years, 7 months
Sparse VMs from Templates - Storage issues
by Shantur Rathore
Hi all,
I have a setup as detailed below
- iSCSI Storage Domain
- Template with Thin QCOW2 disk
- Multiple VMs from Template with Thin disk
oVirt Node 4.4.4
When the VMs boots up it downloads some data to it and that leads to
increase in volume size.
I see that every few seconds the VM gets paused with
"VM X has been paused due to no Storage space error."
and then after few seconds
"VM X has recovered from paused back to up"
Sometimes after a many pause and recovery the VM dies with
"VM X is down with error. Exit message: Lost connection with qemu process."
and I have to restart the VMs.
My questions.
1. How to work around this dying VM?
2. Is there a way to use sparse disks without VM being paused again and
again?
Thanks in advance.
Shantur
3 years, 7 months
about the vm disk type
by Tommy Sway
When I create the VM's image disk, I am not asked to select the following
type of disk.
What is the default value ?
Thanks.
QCOW2 Formatted Virtual Machine Storage
QCOW2 is a storage format for virtual disks. QCOW stands for QEMU
copy-on-write. The QCOW2 format decouples the physical storage layer from
the virtual layer by adding a mapping between logical and physical blocks.
Each logical block is mapped to its physical offset, which enables storage
over-commitment and virtual machine snapshots, where each QCOW volume only
represents changes made to an underlying virtual disk.
The initial mapping points all logical blocks to the offsets in the backing
file or volume. When a virtual machine writes data to a QCOW2 volume after a
snapshot, the relevant block is read from the backing volume, modified with
the new information and written into a new snapshot QCOW2 volume. Then the
map is updated to point to the new place.
Raw
The raw storage format has a performance advantage over QCOW2 in that no
formatting is applied to virtual disks stored in the raw format. Virtual
machine data operations on virtual disks stored in raw format require no
additional work from hosts. When a virtual machine writes data to a given
offset in its virtual disk, the I/O is written to the same offset on the
backing file or logical volume.
Raw format requires that the entire space of the defined image be
preallocated unless using externally managed thin provisioned LUNs from a
storage array.
3 years, 7 months
