Hi Ranga,<br><br>OpenNebula currently doesn't foresee such situation, although I agree they are insteresting one. We will take it into account for future releases. It is tricky since OpenNebula cannot do anything with a network unreachable machine, and if it starts again the VMs, as soon as the host is back with its VMs we will have IP collisions.<br>
<br>About your last question, the algorithm to pick hosts is inside the scheduler, in a separate process, so this is not offered via the OpenNebula core API. You can extract the algorithm from the scheduler though, or you can use the OpenNebula commands to perform the migration so the scheduler gets used.<br>
<br>Hope it helps,<br><br>-Tino<br clear="all"><br>--<br>Constantino Vázquez, Grid Technology Engineer/Researcher: <a href="http://www.dsa-research.org/tinova">http://www.dsa-research.org/tinova</a><br>DSA Research Group: <a href="http://dsa-research.org">http://dsa-research.org</a><br>
Globus GridWay Metascheduler: <a href="http://www.GridWay.org">http://www.GridWay.org</a> <br>OpenNebula Virtual Infrastructure Engine: <a href="http://www.OpenNebula.org">http://www.OpenNebula.org</a><br>
<br><br><div class="gmail_quote">On Tue, Nov 10, 2009 at 11:26 PM, Rangababu Chakravarthula <span dir="ltr"><<a href="mailto:rbabu@hexagrid.com">rbabu@hexagrid.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div bgcolor="#ffffff" text="#000000">
Thank you Tino for your response.<br>
<br>
Let me restate.<br>
<br>
When a host is down, one moves the host status to ERR, keeps polling
the host, keeps the VM status as "RUNNING". Even though VM status is
running, users will not be able to connect to the VM's until host is
back up. <br>
<br>
So, I guess the only solution (if we dont know when the host is going
to come back) is to resubmit the VM and let one create new VM on
different host. What will happen to the old VM's in that case?<br>
<br>
For the last question, we want to migrate before the shutdown happens.
For migration one API needs the destination hostId. one has the
algorithm to pick the best suitable host for a VM. Is that exposed as
API? So that we can get the hostId and do migration.<br>
<br>
Ranga<div><div></div><div class="h5"><br>
<br>
Tino Vazquez wrote:
<blockquote type="cite">Hi Ranga, <br>
<br>
<br>
comments inline,<br clear="all">
<br>
<br>
<div class="gmail_quote">On Tue, Oct 27, 2009 at 6:41 PM, Rangababu
Chakravarthula <span dir="ltr"><<a href="mailto:rbabu@hexagrid.com" target="_blank">rbabu@hexagrid.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><font face="arial, sans-serif"><span style="border-collapse: collapse;">
<div>Opennebula team,</div>
<div><br>
</div>
<div>(a) What mechanism does Opennebula use to monitor hosts? </div>
</span></font></blockquote>
<div><br>
It sends probes (scripts) using ssh<br>
</div>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><font face="arial, sans-serif"><span style="border-collapse: collapse;">
<div><br>
</div>
<div>(b) I would like to know how we can migrate VM's in the
following two scenarios.</div>
<div><br>
</div>
<div>(1) The host might be up but due to some network issues,
opennebula is not able to monitor the host. </div>
<div><span style="white-space: pre;"> </span>(a) Does it move the
host status to ERR? </div>
</span></font></blockquote>
<div><br>
Yep, but it keeps trying to monitor them<br>
</div>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><font face="arial, sans-serif"><span style="border-collapse: collapse;">
<div><span style="white-space: pre;"> </span>(b) What does it do
to the VM's. Does it move to a different state? </div>
</span></font></blockquote>
<div><br>
No, it tries to connect to them.<br>
</div>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><font face="arial, sans-serif"><span style="border-collapse: collapse;">
<div><span style="white-space: pre;"> </span>(c) Is there a
mechanism to automatically migrate those VM's to different host?</div>
</span></font></blockquote>
<div><br>
If the host is unreachable, this is tough to do.<br>
</div>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><font face="arial, sans-serif"><span style="border-collapse: collapse;">
<div><br>
</div>
<div>(2) When somebody manually shutdown the host. Vm's on that
host are not accessible anymore for users. </div>
<div>Is there a way during the shutdown sequence we can trigger a
script to migrate the VM's ? Because, by the time opennebula</div>
<div>finds that host is down users will get effected. How to
address this?</div>
</span></font></blockquote>
<div><br>
This is tricky. If the physical host is shuttted down, there is
virtually not a lot you can do, appart from maybe starting the VMs
again in another host.<br>
</div>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><font face="arial, sans-serif"><span style="border-collapse: collapse;">
<div><br>
</div>
<div>Thanks</div>
<div>Ranga</div>
</span></font></blockquote>
<div><br>
Hope it helps,<br>
<br>
-Tino<br>
</div>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><br>
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</blockquote>
<div><br>
<br>
<br>
--<br>
Constantino Vázquez, Grid Technology Engineer/Researcher: <a href="http://www.dsa-research.org/tinova" target="_blank">http://www.dsa-research.org/tinova</a><br>
DSA Research Group: <a href="http://dsa-research.org" target="_blank">http://dsa-research.org</a><br>
Globus GridWay Metascheduler: <a href="http://www.GridWay.org" target="_blank">http://www.GridWay.org</a> <br>
OpenNebula Virtual Infrastructure Engine: <a href="http://www.OpenNebula.org" target="_blank">http://www.OpenNebula.org</a><br>
<br>
</div>
</div>
<br>
</blockquote>
<br>
</div></div></div>
</blockquote></div><br>