<html><head><style>body{font-family:Helvetica,Arial;font-size:13px}</style></head><body style="word-wrap:break-word"><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">Hi,</div><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">double-check if "nova migrate" option will work for you - it uses a different mechanisms than live-migration and judging by [1] depending on the release of OpenStack you use it might work with LVM backed ephemeral storage. And I seccond Kostiantyn email - we seems to be mixing evacuation with migration.</div><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto"><br></div><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto"><br></div><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">[1] <a href="https://bugs.launchpad.net/nova/+bug/1270305">https://bugs.launchpad.net/nova/+bug/1270305</a></div> <div><br></div><div id="bloop_customfont" style="margin:0px">Regards,</div><div id="bloop_customfont" style="margin:0px">Marcin</div><div><br></div> <br><p class="airmail_on">On 23 Sep 2016 at 16:21:17, Davíð Örn Jóhannsson (<a href="mailto:davidoj@siminn.is">davidoj@siminn.is</a>) wrote:</p> <blockquote type="cite" class="clean_bq"><span><div style="word-wrap:break-word;color:rgb(0,0,0);font-size:14px;font-family:Calibri,sans-serif"><div></div><div>
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<div>Thank you for the clarification. My digging around has thus far only revealed <a href="https://bugs.launchpad.net/nova/+bug/1499405">https://bugs.launchpad.net/nova/+bug/1499405</a> (live migration is not implemented for LVM backed storage)</div>
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<div>If any one has any more info on this subject it would be much appreciated.</div>
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<span style="font-weight:bold">From: </span>"<a href="mailto:Kostiantyn.Volenbovskyi@swisscom.com">Kostiantyn.Volenbovskyi@swisscom.com</a>"<br>
<span style="font-weight:bold">Date: </span>Friday 23 September 2016 at 13:59<br>
<span style="font-weight:bold">To: </span>David Orn Johannsson, "<a href="mailto:marcin.iwinski@gmail.com">marcin.iwinski@gmail.com</a>", "<a href="mailto:openstack-operators@lists.openstack.org">openstack-operators@lists.openstack.org</a>"<br>
<span style="font-weight:bold">Subject: </span>RE: [Openstack-operators] Evacuate host with host ephemeral storage<br>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Trebuchet MS",sans-serif;color:#44546a">Hi,
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<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Trebuchet MS",sans-serif;color:#44546a">here migration and evacuation are getting mixed up.</span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Trebuchet MS",sans-serif;color:#44546a">In migration case you can access the ephemeral storage of your VM and thus you will copy that disk=that file (either
as offline aka ‘cold’ migration or via live migration)</span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Trebuchet MS",sans-serif;color:#44546a">In evacuation case your Compute Host is either unavailable (or assumed-to-be-unavailable) and thus you can’t access
(or assume that you can’t access) whatever is stored on that Compute Host</span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Trebuchet MS",sans-serif;color:#44546a">So in case your emphemeral (=root disk of VM) disk is actually on that Compute Host – then you can’t access that
and thus evacuation will result in rebuild</span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Trebuchet MS",sans-serif;color:#44546a">(=taking original image from Glance and thus typically you lose whatever happened after initial booting)</span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Trebuchet MS",sans-serif;color:#44546a">But in case you have something shared underneath (like NFS) – then --on-shared-storage</span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Trebuchet MS",sans-serif;color:#44546a">nova evacuate EVACUATED_SERVER_NAME HOST_B --on-shared-storage</span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Trebuchet MS",sans-serif;color:#44546a">(I guess that it will detect that automatically even in case)
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<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Trebuchet MS",sans-serif;color:#44546a">But LVM using NFS share – that sounds like something not very-straightforward (not sure if it is OK with OpenStack)</span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Trebuchet MS",sans-serif;color:#44546a">See [1] and [2]
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<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Trebuchet MS",sans-serif;color:#44546a">BR,
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<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Trebuchet MS",sans-serif;color:#44546a">Konstantin</span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Trebuchet MS",sans-serif;color:#44546a">[1]
<a href="http://docs.openstack.org/admin-guide/compute-configuring-migrations.html#section-configuring-compute-migrations">
http://docs.openstack.org/admin-guide/compute-configuring-migrations.html#section-configuring-compute-migrations</a></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Trebuchet MS",sans-serif;color:#44546a">[2]
<a href="http://docs.openstack.org/admin-guide/cli-nova-evacuate.html">http://docs.openstack.org/admin-guide/cli-nova-evacuate.html</a></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Davíð Örn Jóhannsson [<a href="mailto:davidoj@siminn.is">mailto:davidoj@siminn.is</a>]
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<b>Sent:</b> Friday, September 23, 2016 2:12 PM<br>
<b>To:</b> Marcin Iwinski <<a href="mailto:marcin.iwinski@gmail.com">marcin.iwinski@gmail.com</a>>;
<a href="mailto:openstack-operators@lists.openstack.org">openstack-operators@lists.openstack.org</a><br>
<b>Subject:</b> Re: [Openstack-operators] Evacuate host with host ephemeral storage</span></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Calibri",sans-serif;color:black">No I have not, I guess there is nothing else to do than just give it a go :)</span></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Calibri",sans-serif;color:black">Thanks for the pointer</span></p>
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<p class="MsoNormal"><b><span style="font-family:"Calibri",sans-serif;color:black">From:
</span></b><span style="font-family:"Calibri",sans-serif;color:black">Marcin Iwinski<br>
<b>Date: </b>Friday 23 September 2016 at 11:39<br>
<b>To: </b>David Orn Johannsson, "<a href="mailto:openstack-operators@lists.openstack.org">openstack-operators@lists.openstack.org</a>"<br>
<b>Subject: </b>Re: [Openstack-operators] Evacuate host with host ephemeral storage</span></p>
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<p class="airmailon"><span style="font-size:10.5pt;font-family:"Calibri",sans-serif;color:black">On 23 Sep 2016 at 13:25:39, Davíð Örn Jóhannsson (<a href="mailto:davidoj@siminn.is">davidoj@siminn.is</a>) wrote:</span></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Calibri",sans-serif;color:black">I know that using block storage like Cinder you can evacuate instances from hosts, but in my case we are not yet using Cinder or other block storage solutions,
we rely on local ephemeral storage, configured on using LVM</span></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Calibri",sans-serif;color:black">[libvirt]</span></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Calibri",sans-serif;color:black">images_volume_group=vg_ephemeral</span></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Calibri",sans-serif;color:black">Is it possible to evacuate (migrate) ephemeral instances from compute hosts and if so does any one have any experience with that?</span></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Calibri",sans-serif;color:black">Hi Davíð</span></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Calibri",sans-serif;color:black">Have you actually tried the regular "nova migrate UUID" option? It does copy the entire disk to a different compute - but i'm not sure if it's working with LVM.
I've also used [1] ("nova live-migrate --block-migrate UUID") in the past - but unfortunately this also wasn't LVM backed ephemeral storage.</span></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Calibri",sans-serif;color:black">[1] <a href="http://www.tcpcloud.eu/en/blog/2014/11/20/block-live-migration-openstack-environment/">http://www.tcpcloud.eu/en/blog/2014/11/20/block-live-migration-openstack-environment/</a></span></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Calibri",sans-serif;color:black">BR</span></p>
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