<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">2014-12-22 21:50 GMT+08:00 Sylvain Bauza <span dir="ltr"><<a href="mailto:sbauza@redhat.com" target="_blank">sbauza@redhat.com</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<div>Le 22/12/2014 13:37, Alex Xu a écrit :<br>
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<div class="gmail_quote">2014-12-22 10:36 GMT+08:00 Lingxian
Kong <span dir="ltr"><<a 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>2014-12-22 9:21 GMT+08:00 Alex Xu <<a href="mailto:soulxu@gmail.com" target="_blank">soulxu@gmail.com</a>>:<br>
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> 2014-12-22 9:01 GMT+08:00 Lingxian Kong <<a href="mailto:anlin.kong@gmail.com" target="_blank">anlin.kong@gmail.com</a>>:<br>
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</span><span>>> 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>
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</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>
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<div>Yea, you are right, we should doc it if we think this
make sense. Thanks!</div>
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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></div></blockquote><div><br></div><div>Emm...anyway we can resolve it for now?</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div bgcolor="#FFFFFF" text="#000000">
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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></div></blockquote><div><br></div><div>Yes, you understand correctly. Thanks for explain that, that's good for other people to understand what we talking about.</div><div><br></div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div bgcolor="#FFFFFF" text="#000000">
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></div></blockquote><div><br></div><div>Yea, it isn't problem for normal case. But it's problem for VM HA. So I want to ask whether we should tell user if you use *hard* policy, that means you lose the VM HA. If we choice that, maybe we should doc at somewhere to notice user. But if user can have *hard* policy and VM HA at sametime and we aren't break anything(except a little complex code), that's sounds good for user.</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div bgcolor="#FFFFFF" text="#000000">
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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></div></blockquote><div><br></div><div>yes, soft policy didn't have this problem.</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div bgcolor="#FFFFFF" text="#000000">
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HTH,<br>
-Sylvain<span class=""><br>
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--<br>
Regards!<br>
-----------------------------------<br>
Lingxian Kong<br>
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