Thanks Doron & Ofri,
As to the question of cache flash, we already have our consideration and wrote them on our
design page. I have no doubt that your suggestion is more reasonable, we just keep in mind
that expiration is much longer that the time needed to poll all of hosts, so this is
really a potential issue we ignored. Let's make estimation at first, we will have a
try if our schedule is okay.
Doron, we have reserved some effort to research about cluster-level policy. As ovirt is
complete new to our engineers, would we finished our current features (such as ovf and
rest api.) in pipeline at first? After these basic features are ready and we still have
some buffer, we will make some improvement. Is this acceptable?
Thanks again to Doron and Ofri.
From: Doron Fediuck [mailto:email@example.com]
Sent: Thursday, March 28, 2013 10:43 PM
To: Ofri Masad
Cc: engine-devel(a)ovirt.org; Chen, Wei D
Subject: Re: [Engine-devel] Open Attestation integration with oVirt engine proposal has
submitted patchset5 for your review
----- Original Message -----
From: "Ofri Masad" <omasad(a)redhat.com>
To: "Wei D Chen" <wei.d.chen(a)intel.com>
Sent: Thursday, March 28, 2013 12:05:02 PM
Subject: Re: [Engine-devel] Open Attestation integration with oVirt
engine proposal has submitted patchset5 for your review
I would like to raise again the question of the full cache flash for
each stale cache entry found.
This method can cause two unwanted situations:
1. Choosing untrusted host: lets say, for example that you have 1000
host in your pool. you look at the first host in the cache and find
that its attestation hat expired. you refresh the entire pool (there
are 1000 host, that must take some time). by the the time the last
host was refreshed in the pool, the first host may already be expired
again. but since you already checked it - you keep on with your flow
and select that host, even so it has expired and may as well be
2. infinite loop: lets say we'll try to fix what I've described in
1. then, we need to check again if the host has expired before we
select it. if it is, the entire refresh process starts again. this
could potentially go on forever (unless I'm missing something, and
the expiration is much longer then the full re-cache process).
Instead of re-caching the full cache we can do as follows:
- hold the cache entries sorted by expiration (if the expiration
time is the same for all hosts, so a queue is enough).
- each time we need a new trusted host - select from the unexpired
hosts, refresh all expired hosts (in one query).
- if all hosts are expired - we can wait for the first host to be
defined trusted by the attestation server and select that host.
Dave, adding another suggestion on top of Ofri's;
Generally speaking, a cluster of hosts defines many joint features (such as CPU level),
which means that in the same cluster we would expect to be able to freely migrate a VM
from one host to another.
Current trust-pools design is breaking this concept, as you introduce a state where a VM
cannot migrate from a 'safe' host into an 'unsafe'
This leads me to the suggestion of having attestation as a cluster policy rather than a
VM-level property. It means that all hosts in this cluster are constantly being monitored
to be safe. If a host is declared as unsafe in the Attestation server, it will become
non-operational in the engine. This will simplify the implementation since you have
everything ready for you once you have a 'safe' cluster and no need to do any
So in this way you keep current concepts while simplifying the implementation with very
little worries of performance issues.
Can you please share your thoughts on this suggestion?
----- Original Message -----
> From: "Wei D Chen" <wei.d.chen(a)intel.com>
> To: engine-devel(a)ovirt.org
> Sent: Friday, March 22, 2013 11:34:55 AM
> Subject: [Engine-devel] Open Attestation integration with oVirt
> engine proposal has submitted patchset5 for your review
> Hi all,
> Before submitting this patch set, we has updated our design page,
> and new feature about VM template has added to this patchset. In
> patchset a lot of frontend changes has been imported.
> Welcome to review our patchset and thanks advance for your
> Detailed description: http://wiki.ovirt.org/Trusted_compute_pools
> In this patch set, follow changes has been introduced:
> 1. GUI changes to support for creating a trusted VM on a trusted
> physical host.
> 2. View/Edit VM changes to enable end user switch between three run
> on options.
> 3. Template relevant changes to support end user create a trusted VM
> template and create trusted VM based on this template afterwards.
> 4. Bug fixing and code cleanup.
> 5. wiki design page update.
> Best Regards,
> Dave Chen