<html><body bgcolor="#FFFFFF"><div><div>+1</div><div><br></div><div>Some people think Cloud means 'magic' and failed physical instances should recover to the previous state. Most of the times this is not possible at app level, and I wonder if desirable.</div><div><br></div><div>Still, Nova lacks of features like 'HA' instances and instances running on remote block storage (like EBS backed instances in AWS).I think this is basic for self-healing features needed for real DR.</div><div><br><br>Enviado desde mi iPad</div><div><br>El 02/04/2011, a las 22:46, Jesse Andrews <<a href="mailto:anotherjesse@gmail.com">anotherjesse@gmail.com</a>> escribió:<br><br></div><div></div><blockquote type="cite"><div><p>What to do when an instance dies is application specific.</p>
<p>Some applications may not care, autoscaling back to the proper size by themselves. Other applications may need the resources to be returned in the most recent state.</p>
<p>Currently openstack requires the user to handle recovery.</p>
<p>I expect there will be an option to mark a virtual machine as "HA" which would attempt to relaunch on crashes. How exactly to implement it will depend on the cloud requirements. If the instances are backed to a SAN or distributed filesystem (like ceph) the VM can be relaunched with all state that has been flushed to disk. On a cloud with local disk only, the scheduled snapshotting could allow the vm to a recent state.</p>
<p>Or HA could mean relaunch the image (ala autoscale)</p>
<p>What use case are you thinking about?</p>
<p>Jesse</p>
<div class="gmail_quote">On Apr 2, 2011 1:33 PM, "Marek Denis" <<a href="mailto:marek@octogan.net"><a href="mailto:marek@octogan.net">marek@octogan.net</a></a>> wrote:<br type="attribution">> Hello,<br>> <br>> I have been trying to find out some info about features OpenStack <br>
> provide and still cannot figure out whether 'cloud features' are <br>> available by default. By 'cloud features' I mean proper handling <br>> situations where we have many instances running on many different <br>
> hardware servers. Suddently one server (physically) goes down, something <br>> bad happened. How will the OpenStack as a cloud behave by default? Will <br>> it run all the lost instances on other hardware servers or this should <br>
> be specifically configured or programmed? How about data replication? <br>> Users shouldn't notice anything, as all the instances are ran in the <br>> cloud. Is it available by default? I couldn't find any docs that would <br>
> explain these topics in a detailed way. Thanks for your explanation.<br>> -- <br>> regards<br>> <br>> M<br>> <br>> <br>> _______________________________________________<br>> Mailing list: <a href="https://launchpad.net/~openstack"><a href="https://launchpad.net/~openstack">https://launchpad.net/~openstack</a></a><br>
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