On Thu, May 24, 2018 at 2:20 PM wodel youchi <wodel.you...@gmail.com> wrote:
> Hi, > > Excuse the English :) > > Need some advice regarding the use of high availability software on VMs on > oVirt. > > We are migrating a physical high available application to oVirt. > The HA platform uses pacemaker, it contains two nodes and a shared > storage, fence (stonith) is configured to use ILO. > > I know that oVirt offers HA for VM, but this HA is not application aware, > if a service crashes on the VM, it will not be detected. > Fencing could be achieved by fence agent rhev. > > My questions are about the best way to migrate this platform to oVirt. > > - Is it a good idea to make both VMs (formally nodes) Highly-Available > VMs? or may be pin each one of them to a particular hypervisor and/or use > VM-Affinity? > If the VM should be highly available, you should not pin them to any host. Pinning them will make sure the vm will *not* be available when the host is down :-) So you probably want to use HA VM - with a VM lease. Warning: do not use HA VM without a VM lease, this will make sure that you will have split-brain eventually. > - I am thinking about the situation where the hypervisor containing one of > the VMs crashes, what will be the behavior of the the fence agent on the > application? > Not sure what do you mean by "crashes". If the hypervisor lost power, HA VM with a VM lease will be started on another hypevisor. The guest agent on the VM will not be able to do anything since it is not running :-) > - if the crashed VM is not HA, it will not start on another hypervisor, > so the fence agent will try to fence a VM that does not exist anymore, and > it will stuck. > - if the crashed VM is HA, it will be started on another hypervisor, > but what will happen with the fence agent? I think that one VM will fence > the other one, and the application will still be unreachable for a longer > period. > Not clear what fence agent are you talking about. > - What about the shared storage, we will use a shared disk on oVirt which > does not support snapshot > What is the question? > > - What are the things to avoid? > I think in general, don't try to have two mechanisms that try to do the same. Either use your HA solution or oVirt HA solution, but not both in the same time. Nir
_______________________________________________ Users mailing list -- users@ovirt.org To unsubscribe send an email to users-le...@ovirt.org
