> > Also I have a question regarding domain-0. How will it be represented?
Is
> > it a VM - the fact that 'guest' is written in the description of the
VM
> > class makes me think that this might not be the case.
>
> That's a very good question. My instinct is to say that dom-0 shouldn't
> be part of the list of domains, and that it should be considered part of
> the infrastructure. When we have driver domains, and HVM stub domains,
> there will be many of these domains, representing different parts of the
> infrastructure, and it seems to me that these are not the same as
> "guests" or "VMs". A VM can be rebooted, migrated (possibly), each time
> keeping the same VM, but ending up with a different domain. A VM is
> ultimately the reason that users are running Xen, and the thing that
> makes it useful. For this reason, I don't think that domain 0 is a VM.
>
> On the other hand, these things are still useful entities -- you might
> want to monitor the CPU cost due to each of them, tweak their scheduling
> parameters, and so on. So perhaps they are close enough to being a VM
> that we should put them in there, and cope with the slightly special
> nature of them as best we can.
>
> What do people think?
>
> Ewan.
>
I think there are other ways to denote infrastructure VMs, or any other
special VMs. They don't all have to be managed by the same guest VM
management software/infrastructure -- e.g., there could be an
infrastructure management control plane, or as we in the security space
might call it, a security/trust domain consisting a set of VMs distributed
among many platforms that just happen to be used for platform management.
While these management VMs might not be migratable, you might still want
to manage them as you suggested, as well as managing hot back-ups/clones,
etc.
In the future when there are multiple dom-0's, or rather dom-0 is
disaggregated, there may still be only one with the designation of "host".
-Ron
Is
> > it a VM - the fact that 'guest' is written in the description of the
VM
> > class makes me think that this might not be the case.
>
> That's a very good question. My instinct is to say that dom-0 shouldn't
> be part of the list of domains, and that it should be considered part of
> the infrastructure. When we have driver domains, and HVM stub domains,
> there will be many of these domains, representing different parts of the
> infrastructure, and it seems to me that these are not the same as
> "guests" or "VMs". A VM can be rebooted, migrated (possibly), each time
> keeping the same VM, but ending up with a different domain. A VM is
> ultimately the reason that users are running Xen, and the thing that
> makes it useful. For this reason, I don't think that domain 0 is a VM.
>
> On the other hand, these things are still useful entities -- you might
> want to monitor the CPU cost due to each of them, tweak their scheduling
> parameters, and so on. So perhaps they are close enough to being a VM
> that we should put them in there, and cope with the slightly special
> nature of them as best we can.
>
> What do people think?
>
> Ewan.
>
I think there are other ways to denote infrastructure VMs, or any other
special VMs. They don't all have to be managed by the same guest VM
management software/infrastructure -- e.g., there could be an
infrastructure management control plane, or as we in the security space
might call it, a security/trust domain consisting a set of VMs distributed
among many platforms that just happen to be used for platform management.
While these management VMs might not be migratable, you might still want
to manage them as you suggested, as well as managing hot back-ups/clones,
etc.
In the future when there are multiple dom-0's, or rather dom-0 is
disaggregated, there may still be only one with the designation of "host".
-Ron