On Wed, Mar 24, 2021 at 11:04 PM Ian Easter <ieaster(a)telvue.com> wrote:
I have had to install a Hosted-Engine a few times in my environment. There have been
some hardware issues and power issues that left the HE unrecoverable.
In this situation, would the Standalone Engine install be more viable and less prone to
become inoperable due to the previous issues?
My assumption would be to have a head baremetal server run the Engine to control and
maintain my blades.
With a standalone engine, it's your responsibility to take care of the
If it breaks, it's up to you to recover.
If you are an experienced sysadmin, you might find this comfortable.
Perhaps you know well how to identify what got broken, fix/replace it,
restore your backups, etc.
With a hosted-engine, instead of a physical machine, you have a
virtual machine. This VM is controlled by a set of daemons, including
their data/configuration scattered around several places.
Collectively, they are called 'ovirt-hosted-engine-ha' (together with
other stuff, obviously - qemu/libvirt/vdsm, systemd, ...), or HA for
If you know HA as well as your physical hardware, then I do not think
there is an essential difference. If you know well where to look if
there are problems, how to replace/fix stuff, restore backups, etc.,
then it's in theory the same.
But: It's up to you to get to know HA. And this is knowledge that is
to a large extent oVirt-specific and unrelated to your previous
knowledge and experience.
HA obviously has other advantages - it provides cheap HA (that's why
it's named like that) using your existing hardware, it's easy to set
up - at least compared to setting up an HA oVirt engine using external
HA means (e.g. linux-ha/corosync/pacemaker/heartbeat/VCS etc.), and it
often works well. But to feel comfortable with it, you do have to
If HA's extra features etc. are not relevant for you, and having a
single BM machine for the engine is ok for your use case, and you know
Linux well but do not know well HA, and have extra hardware/rack space
to allocate for the engine machine, then a standalone engine is
probably better for you. Same if you do this mainly for
debugging/learning/etc. - a standalone engine is simpler, easier to
understand and debug.
Just my 2c.