<html>
<head>
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
</head>
<body text="#000000" bgcolor="#FFFFFF">
<div class="moz-cite-prefix">Le 21/01/2014 15:28, Day, Phil a
écrit :<br>
</div>
<blockquote
cite="mid:BD26CCD58723F74AA8E6BCB31052A1F006F898B4@G6W2490.americas.hpqcorp.net"
type="cite">
<pre wrap="">
</pre>
<blockquote type="cite">
<blockquote type="cite">
<pre wrap="">
I think there is clear water between this and the existing aggregate based
</pre>
</blockquote>
<pre wrap="">isolation. I also think this is a different use case from reservations. It's
*mostly* like a new scheduler hint, but because it has billing impacts I think it
needs to be more than just that - for example the ability to request a
dedicated instance is something that should be controlled by a specific role.
</pre>
<blockquote type="cite">
<pre wrap="">
</pre>
</blockquote>
<pre wrap="">
I agree with that, that's another scheduler filter with extra scheduler hint,
plus a notification message on the AMQP queue thanks to an handler. That's
not role of Nova but Ceilometer to handle billable items and meters
consolidation.
That said, AWS dedicated instances are backed by VPC, so that's not fairly
identical from what you propose here. Here the proposal is more likely
making me thinking of AWS "reserved" instances without a contractual
period.
IMHO, this model is interesting but hard to use for operators, because they
don't have visibility on the capacity. Anyway, if Nova would provide this
feature, Climate would be glad using it (and on a personal note, I would be
glad contributing to it).
</pre>
</blockquote>
<pre wrap="">
I think VPC in AWS is more of a network construct that anything to do with specific hosts - (i.e the difference between running nova-net or neutron in flat mode vs vlan or vxlan mode).
</pre>
</blockquote>
<br>
"Dedicated instances" in the AWS terminology are for VPC tenants and
are not subject to a contractual period. "Reserved instances" are
actually a billing model (with a period of either 1y or 3yrs) for
charging a certain number of instances with discounted rates and a
one-time fee. <br>
<br>
So, yes, dedicated instances in AWS are what we could call a
"private cloud" with internal networking (a personal CIDR), so
that's why I said that your proposal is more likely related to AWS
reserved instances model (without a term reservation)<br>
<br>
<br>
<blockquote
cite="mid:BD26CCD58723F74AA8E6BCB31052A1F006F898B4@G6W2490.americas.hpqcorp.net"
type="cite">
<pre wrap="">
I agree that it is hard for an operator to work out how to charge for this - in effect it comes down to some sort of statistical model to work out what additional premium you need to charge to recover the cost of the capacity that is now not usable by other tenants. This kind of thing becomes easier at scale than it is for very small systems. So some/many operators may decide that they don't want to offer it (which is why it needs to be a specific feature in my mind, even if that does mean a minor bump to the API version in V3 and a new extension to provide the new option in V2 - sorry Jay). It probably even merits its own specific quota value (max number of dedicated instances). I'm not sure that its really that much harder to manage than any other capacity issue though - for example if you define a flavor that occupies </pre>
</blockquote>
<br>
Again, I was about designing this for Climate : provided the
operator specifies a max percentage of hosts to dedicate, that could
do the work. Perhaps you should take a look on the current Climate
review [1] for electing the hosts, we already thought about
overprovisioning and capacity planning. That's particularly why I'm
thinking that capacity planning needs reservations in place
(explicitly defined by users, or implicitely calculated) in order to
do the maths.<br>
<br>
-Sylvain<br>
<meta http-equiv="content-type" content="text/html;
charset=ISO-8859-1">
<br>
[1] : <a
href="https://review.openstack.org/#/c/54285/27/climate/plugins/oshosts/host_plugin.py">https://review.openstack.org/#/c/54285/27/climate/plugins/oshosts/host_plugin.py</a><br>
<br>
</body>
</html>