<html>
<head>
<meta content="text/html; charset=windows-1252"
http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
<br>
<div class="moz-cite-prefix">Le 22/12/2014 13:37, Alex Xu a écrit :<br>
</div>
<blockquote
cite="mid:CAH7mGatQeRi1MkmvQyjQhsm3ypEm77kh5+q373DEwvP1UNfaDg@mail.gmail.com"
type="cite">
<div dir="ltr"><br>
<div class="gmail_extra"><br>
<div class="gmail_quote">2014-12-22 10:36 GMT+08:00 Lingxian
Kong <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:anlin.kong@gmail.com" target="_blank">anlin.kong@gmail.com</a>></span>:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex"><span
class="">2014-12-22 9:21 GMT+08:00 Alex Xu <<a
moz-do-not-send="true" href="mailto:soulxu@gmail.com">soulxu@gmail.com</a>>:<br>
><br>
><br>
> 2014-12-22 9:01 GMT+08:00 Lingxian Kong <<a
moz-do-not-send="true"
href="mailto:anlin.kong@gmail.com">anlin.kong@gmail.com</a>>:<br>
>><br>
<br>
>><br>
</span><span class="">>> but what if the compute
node is back to normal? There will be<br>
>> instances in the same server group with
affinity policy, but located<br>
>> in different hosts.<br>
>><br>
><br>
> If operator decide to evacuate the instance from
the failed host, we should<br>
> fence the failed host first.<br>
<br>
</span>Yes, actually. I mean the recommandation or
prerequisite should be<br>
emphasized somewhere, e.g. the Operation Guide, otherwise
it'll make<br>
things more confused. But the issue you are working around
is indeed a<br>
problem we should solve.<br>
<div class="HOEnZb">
<div class="h5"><br>
</div>
</div>
</blockquote>
<div><br>
</div>
<div>Yea, you are right, we should doc it if we think this
make sense. Thanks!</div>
<div> </div>
</div>
</div>
</div>
</blockquote>
<br>
As I said, I'm not in favor of adding more complexity in the
instance group setup that is done in the conductor for basic race
condition reasons.<br>
<br>
If I understand correctly, the problem is when there is only one
host for all the instances belonging to a group with affinity filter
and this host is down, then the filter will deny any other host and
consequently the request will fail while it should succeed.<br>
<br>
Is this really a problem ? I mean, it appears to me that's a normal
behaviour because a filter is by definition an *hard* policy.<br>
<br>
So, provided you would like to implement *soft* policies, that
sounds more likely a *weigher* that you would like to have : ie.
make sure that hosts running existing instances in the group are
weighted more than other ones so they'll be chosen every time, but
in case they're down, allow the scheduler to pick other hosts.<br>
<br>
HTH,<br>
-Sylvain<br>
<br>
<br>
<br>
<br>
<blockquote
cite="mid:CAH7mGatQeRi1MkmvQyjQhsm3ypEm77kh5+q373DEwvP1UNfaDg@mail.gmail.com"
type="cite">
<div dir="ltr">
<div class="gmail_extra">
<div class="gmail_quote">
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div class="HOEnZb">
<div class="h5">
--<br>
Regards!<br>
-----------------------------------<br>
Lingxian Kong<br>
<br>
_______________________________________________<br>
OpenStack-dev mailing list<br>
<a moz-do-not-send="true"
href="mailto:OpenStack-dev@lists.openstack.org">OpenStack-dev@lists.openstack.org</a><br>
<a moz-do-not-send="true"
href="http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev"
target="_blank">http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev</a><br>
</div>
</div>
</blockquote>
</div>
<br>
</div>
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
<pre wrap="">_______________________________________________
OpenStack-dev mailing list
<a class="moz-txt-link-abbreviated" href="mailto:OpenStack-dev@lists.openstack.org">OpenStack-dev@lists.openstack.org</a>
<a class="moz-txt-link-freetext" href="http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev">http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev</a>
</pre>
</blockquote>
<br>
</body>
</html>