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</o:shapelayout></xml><![endif]--></head><body bgcolor=white lang=DE link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Hi all,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>thank you very much for your answers.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>So:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><span style='mso-list:Ignore'>1)<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Of course, we have UPS. More than one, in our server room, and of course they will send an advice to the host if they are on battery<o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><span style='mso-list:Ignore'>2)<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>My question was: “what can I do, so that in case of Kernel Panic or similar, the VM will be migrated (live or not) to another host?”<o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><span style='mso-list:Ignore'>3)<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I’d like to have a shutdown-script on the host that put the host in Maintenance and wait until it’s done, so that I can just shutdown or reboot it without any other action. Is it possible? It would help to manage the power failure, too, assuming that other hosts have better UPS (it can be possible…)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Thanks a lot<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Mit freundlichen Grüßen<br><br>Luca Bertoncello<br><br>-- <br>Besuchen Sie unsere Webauftritte:<o:p></o:p></span></p><table class=MsoNormalTable border=0 cellspacing=0 cellpadding=0><tr><td style='padding:0cm 0cm 0cm 0cm'><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><a href="http://www.queo.biz/">www.queo.biz</a><o:p></o:p></span></p></td><td style='padding:0cm 0cm 0cm 0cm'><p class=MsoNormal style='margin-left:3.75pt'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Agentur für Markenführung und Kommunikation<o:p></o:p></span></p></td></tr><tr><td style='padding:0cm 0cm 0cm 0cm'><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><a href="http://www.queoflow.com/">www.queoflow.com</a><o:p></o:p></span></p></td><td style='padding:0cm 0cm 0cm 0cm'><p class=MsoNormal style='margin-left:3.75pt'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>IT-Consulting und Individualsoftwareentwicklung<o:p></o:p></span></p></td></tr></table><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><br>Luca Bertoncello<br>Administrator<o:p></o:p></span></p><table class=MsoNormalTable border=0 cellspacing=0 cellpadding=0><tr><td style='padding:0cm 0cm 0cm 0cm'><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Telefon:<o:p></o:p></span></p></td><td style='padding:0cm 0cm 0cm 0cm'><p class=MsoNormal style='margin-left:3.75pt'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>+49 351 21 30 38 0<o:p></o:p></span></p></td></tr><tr><td style='padding:0cm 0cm 0cm 0cm'><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Fax:<o:p></o:p></span></p></td><td style='padding:0cm 0cm 0cm 0cm'><p class=MsoNormal style='margin-left:3.75pt'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>+49 351 21 30 38 99<o:p></o:p></span></p></td></tr><tr><td style='padding:0cm 0cm 0cm 0cm'><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>E-Mail:<o:p></o:p></span></p></td><td style='padding:0cm 0cm 0cm 0cm'><p class=MsoNormal style='margin-left:3.75pt'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><a href="mailto:l.bertoncello@queo-group.com">l.bertoncello@queo-group.com</a><o:p></o:p></span></p></td></tr></table><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><br>queo GmbH<br>Tharandter Str. 13<br>01159 Dresden<br>Sitz der Gesellschaft: Dresden<br>Handelsregistereintrag: Amtsgericht Dresden HRB 22352<br>Geschäftsführer: Rüdiger Henke, André Pinkert<br>USt-IdNr.: DE234220077</span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div style='border:none;border-left:solid blue 1.5pt;padding:0cm 0cm 0cm 4.0pt'><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'> users-bounces@ovirt.org [mailto:users-bounces@ovirt.org] <b>On Behalf Of </b>matthew lagoe<br><b>Sent:</b> Thursday, September 17, 2015 9:56 PM<br><b>To:</b> 'Alex Crow'; 'Yaniv Kaul'<br><b>Cc:</b> users@ovirt.org<br><b>Subject:</b> Re: [ovirt-users] Automatically migrate VM between hosts in the same cluster<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>There are PDU’s that you can monitor power draw per port and that would kind of tell you if a PSU failed as the load would be 0<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:windowtext'>From:</span></b><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:windowtext'> <a href="mailto:users-bounces@ovirt.org">users-bounces@ovirt.org</a> [<a href="mailto:users-bounces@ovirt.org">mailto:users-bounces@ovirt.org</a>] <b>On Behalf Of </b>Alex Crow<br><b>Sent:</b> Thursday, September 17, 2015 12:31 PM<br><b>To:</b> Yaniv Kaul <<a href="mailto:ykaul@redhat.com">ykaul@redhat.com</a>><br><b>Cc:</b> <a href="mailto:users@ovirt.org">users@ovirt.org</a><br><b>Subject:</b> Re: [ovirt-users] Automatically migrate VM between hosts in the same cluster<o:p></o:p></span></p></div></div><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><span lang=EN-US>I don't really think this is practical:<br><br><o:p></o:p></span></p><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><div><div><div><p class=MsoNormal><span lang=EN-US>- If the PSU failed, your UPS could alert you. If you have one...<o:p></o:p></span></p></div></div></div></div></blockquote><p class=MsoNormal style='margin-bottom:12.0pt'><span lang=EN-US><br>If you have only one PSU in a host, a UPS is not going to stop you losing all the VMs on that host. OK, if you had N+1 PSUs, you may be able to monitor for this (IPMI/LOM/DRAC etc)and use the API to put a host into maintenance. Also a lot of people rely on low-cost white-box servers and decide that it's OK if a single PSU in a host dies, as, well, we have HA to start on other hosts. If they have N+1 PSUs in the hosts do they really have to migrate everything off? Swings and roundabouts really.<br><br>I'm also not sure I've seen any practical DC setups where a UPS can monitor the load for every single attached physical machine and figure out that one of the redundant PSUs in it has failed - I'd love to know if there are as that would be really cool.<br><br><o:p></o:p></span></p><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><div><div><div><p class=MsoNormal><span lang=EN-US>- If the machine is going down in an ordinary flow, surely it can be done. <o:p></o:p></span></p></div></div></div></div></blockquote><p class=MsoNormal style='margin-bottom:12.0pt'><span lang=EN-US><br>Isn't that what "Maintenance mode" is for?<br><br><o:p></o:p></span></p><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><div><div><div><p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p></div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0cm 0cm 0cm 6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0cm;margin-bottom:5.0pt'><p class=MsoNormal><span lang=EN-US><br>Even if it was a network failure and the host was still up, how would you live migrate a VM from a host you can't even talk to?<o:p></o:p></span></p></blockquote><div><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US>It could be suspended to disk (local) - if the disk is available.<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US>Then the decision if it is to be resumed from local disk or not (as it might be HA'ed and is running elsewhere) need to be taken later, of course.<o:p></o:p></span></p></div></div></div></div></blockquote><p class=MsoNormal style='margin-bottom:12.0pt'><span lang=EN-US><br>Yes, but that's not even remotely possible with Ovirt right now. I was trying to be practical as the OP has only just started using Ovirt and I think it might be a bit much to ask him to start coding up what he'd like.<br><br><o:p></o:p></span></p><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><div><div><div><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p></div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0cm 0cm 0cm 6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0cm;margin-bottom:5.0pt'><p class=MsoNormal><span lang=EN-US><br>The only way you could do it was if you somehow magically knew far enough in advance that the host was about to fail (!) and that gave enough time to migrate the machines off. But how would you ever know that "machine <a href="http://quux.bar.net" target="_blank">quux.bar.net</a> is going to fail in 7 minutes"?<o:p></o:p></span></p></blockquote><div><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US>I completely agree there are situations in which you can't foresee the failure. <o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US>But in many, you can. In those cases, it makes sense for the host to self-initiate 'move to maintenance' mode. The policy of what to do when 'self-moving-to-maintenance-mode' could be pre-fetched from the engine.<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US>Y.<o:p></o:p></span></p></div></div></div></div></blockquote><p class=MsoNormal><span lang=EN-US><br>Hmm, I would love that to be true. But I've seen so many so called "corner-cases" that I now think the failure area in a datacenter is a fractal with infinite corners. Yes, you could monitor SMART on local drives, pick up uncorrected ECC errors, use "sensors" to check for sagging voltages or high temps, but I don't think you can ever hope to catch everything, and you could end up doing a migration "storm" for . I've had more than enough of "Enterprise Spec" switches suddenly going nuts and spamming corrupt MACs all over the LAN to know you can't ever account for everything.<br><br>I think it's better to adopt the model of redundancy in software and services, so no-one even notices if a VM host goes away, there's always something else to take up the slack. Just like the origins of the Internet - the network should be dumb and the applications should cope with it! Any infrastructure that can't cope with the loss of a few VMs for a few minutes probably needs a refresh.<br><br>Cheers<br><br>Alex<br><br><br><br><br><br>. <o:p></o:p></span></p></div></div></body></html>