10:50 a.m.
For migration between hosts you need a shared storage. SAN, Gluster,
CEPH, NFS, iSCSI are among the ones already supported (CEPH is a little bit experimental).
Sounds like I'll be using NFS or Gluster after all.
Thank you.
The engine is just a management layer. KVM/qemu has that option a
long time ago, yet it's some manual work to do it.
Yeah, this environment that
I'm building is expected to grow over time (although that growth could go slowly), so
I'm trying to architect things properly now to make future growth easier to deal with.
I'm also trying to balance availability concerns with budget constraints starting
out.
Given that NFS would also be a single point of failure, I'll probably go with Gluster,
as long as I can fit the storage requirements into the overall budget.
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‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Monday, June 22, 2020 6:31 AM, Strahil Nikolov via Users <users(a)ovirt.org>
wrote:
На 22 юни 2020 г. 11:06:16 GMT+03:00, David White via
Usersusers(a)ovirt.org написа:
> Thank you and Strahil for your responses.
> They were both very helpful.
>
> > I think a hosted engine installation VM wants 16GB RAM
configured
> > though I've built older versions with 8GB RAM.
> > For modern VMs CentOS8 x86_64 recommends at least 2GB for a host.
> > CentOS7 was OK with 1, CentOS6 maybe 512K.
> > The tendency is always increasing with updated OS versions.
>
> Ok, so to clarify my question a little bit, I'm trying to
figure out
> how much RAM I would need to reserve for the host OS (or oVirt Node).
> I do recall that CentOS / RHEL 8 wants a minimum of 2GB, so perhaps
> that would suffice?
> And then as you noted, I would need to plan to give the engine 16GB.
I run my engine on 4Gb or RAM, but i have no more than 20 VMs, the
larger the setup - the more ram for the engine is needed.
> > My minimum ovirt systems were mostly 48GB 16core, but most
are now
> > 128GB 24core or more.
>
> But this is the total amount of physical RAM in your systems,
correct?
> Not the amount that you've reserved for your host OS?I've spec'd out
> some hardware, and am probably looking at purchasing two PowerEdge
> R820's to start, each with 64GB RAM and 32 cores.
>
> > While ovirt can do what you would like it to do concerning
a single
> > user interface, but with what you listed,
> > you're probably better off with just plain KVM/qemu and using
> > virt-manager for the interface.
>
> Can you migrate VMs from 1 host to another with virt-manager,
and can
> you take snapshots?
> If those two features aren't supported by virt-manager, then that would
> almost certainly be a deal breaker.
The engine is just a management layer. KVM/qemu has that option a
long time ago, yet it's some manual work to do it.
>
> Come to think of it, if I decided to use local storage on each
of the
> physical hosts, would I be able to migrate VMs?
> Or do I have to use a Gluster or NFS store for that?
For migration between hosts you need a shared storage. SAN, Gluster,
CEPH, NFS, iSCSI are among the ones already supported (CEPH is a little bit experimental).
>
> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
> On Sunday, June 21, 2020 5:58 PM, Edward Berger edwberger(a)gmail.com
> wrote:
>
> > While ovirt can do what you would like it to do concerning
a single
> > user interface, but with what you listed,
> > you're probably better off with just plain KVM/qemu and using
> > virt-manager for the interface.
>
> > Those memory/cpu requirements you listed are really tiny
and I
> > wouldn't recommend even trying ovirt on such challenged systems.
> > I would specify at least 3 hosts for a gluster hyperconverged system,
> > and a spare available that can take over if one of the hosts dies.
>
> > I think a hosted engine installation VM wants 16GB RAM
configured
> > though I've built older versions with 8GB RAM.
> > For modern VMs CentOS8 x86_64 recommends at least 2GB for a host.
> > CentOS7 was OK with 1, CentOS6 maybe 512K.
> > The tendency is always increasing with updated OS versions.
>
> > My minimum ovirt systems were mostly 48GB 16core, but most
are now
> > 128GB 24core or more.
>
> > ovirt node ng is a prepackaged installer for an oVirt
> > hypervisor/gluster host, with its cockpit interface you can create and
> > install the hosted-engine VM for the user and admin web interface. Its
> > very good on enterprise server hardware with lots of RAM,CPU, and
> > DISKS.
>
> > On Sun, Jun 21, 2020 at 4:34 PM David White via Users
> > users(a)ovirt.org wrote:
>
> > > I'm reading through all of the documentation at
> > > https://ovirt.org/documentation/, and am a bit overwhelmed with all of
> > > the different options for installing oVirt.
> >
> > >
>
> > > > My particular use case is that I'm looking for a way to manage
VMs
> > > > on multiple physical servers from 1 interface, and be able to deploy
> > > > new VMs (or delete VMs) as necessary. Ideally, it would be great if I
> > > > could move a VM from 1 host to a different host as well, particularly
> > > > in the event that 1 host becomes degraded (bad HDD, bad processor,
> > > > etc...)
> >
> > >
>
> > > > I'm trying to figure out what the difference is between an oVirt
> > > > Node and the oVirt Engine, and how the engine differs from the
Manager.
> >
> > >
>
> > > > I get the feeling that `Engine` = `Manager`. Same thing. I further
> > > > think I understand the Engine to be essentially synonymous with a
> > > > vCenter VM for ESXi hosts. Is this correct?
> >
> > >
>
> > > > If so, then what's the difference between the `self-hosted` vs
the
> > > > `stand-alone` engines?
> >
> > >
>
> > > > oVirt Engine requirements look to be a minimum of 4GB RAM and
> > > > 2CPUs.
> >
> > > > oVirt Nodes, on the other hand, require only 2GB RAM.
> > > > Is this a requirement just for the physical host, or is that how
> > > > much RAM that each oVirt node process requires? In other words, if I
> > > > have a physical host with 12GB of physical RAM, will I only be able
to
> > > > allocate 10GB of that to guest VMs? How much of that should I
dedicated
> > > > to the oVirt node processes?
> >
> > >
>
> > > > Can you install the oVirt Engine as a VM onto an existing oVirt
> > > > Node? And then connect that same node to the Engine, once the Engine
is
> > > > installed?
> >
> > >
>
> > > > Reading through the documentation, it also sounds like oVirt Engine
> > > > and oVirt Node require different versions of RHEL or CentOS.
> >
> > > > I read that the Engine for oVirt 4.4.0 requires RHEL (or CentOS)
> > > > 8.2, whereas each Node requires 7.x (although I'll plan to just
use the
> > > > oVirt Node ISO).
> >
> > >
>
> > > > I'm also wondering about storage.
> > > > I don't really like the idea of using local storage, but a single
> > > > NFS server would also be a single point of failure, and Gluster would
> > > > be too expensive to deploy, so at this point, I'm leaning towards
using
> > > > local storage.
> >
> > >
>
> > > > Any advice or clarity would be greatly appreciated.
>
> > > > Thanks,
> > > > David
>
> > > > Sent with ProtonMail Secure Email.
>
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> >
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> > >
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