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<p class="MsoNormal"><span lang="EN-US">The current VM template patches heavily depend on the ‘live snapshot’<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">feature. This works well for some storage types (rdb, sheeddog, …), but<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">not for all. Most important it does not work well with qcow2 files.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">But the major drawback is that our backup/restore does not work<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">well with ‘live snapshots’.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">So using ‘live snapshots’ for templates has the following drawbacks:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">- does not work well for qcow2 files<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">- does not work with LVM<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">- we are not able to backup/restore such templates<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">- difficult to copy/migrate such templates<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">The following is just an idea to improve things. I would like that<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Alexandre poof-read and comment on that. I will explain all<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">things using ‘local’ file storage first.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:14.0pt">Terms and Definitions:<o:p></o:p></span></b></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span lang="EN-US">Disk Image</span></b><span lang="EN-US">: Also called ‘volumes’. We use the following volume naming:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> local:100/vm-100-disk-1.raw<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">The real image file resides at (path):<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> /var/lib/vz/images/100/vm-100-disk-1.raw<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span lang="EN-US">Base image</span></b><span lang="EN-US">: A ‘read only’ image file which can be ‘cloned’. We can<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">use the following volume naming:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> local:base/an-arbitray-name.raw<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">The real images resides at (path):<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"> /var/lib/vz/images/base/an-arbitray-name.raw<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">We can easily clone that by creating a qcow2 image which use this<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">as base image.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">You could also name that a ‘template disk’.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span lang="EN-US">Cloned image: </span></b><span lang="EN-US">A disk image which refers to a ‘base image’.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span lang="EN-US">VM templates</span></b><span lang="EN-US">: A VM only using base images. You can never start such VM because<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">the disk images are read-only. But copy/clone/backup/restore should be very easy<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">to implement.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:14.0pt">Usage scenario<o:p></o:p></span></b></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span lang="EN-US">Base images</span></b><span lang="EN-US">:
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">When we create/add disks, we can allow to choose from those<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">base images to create cloned images.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span lang="EN-US">VM templates</span></b><span lang="EN-US">:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">There are basically two ways to create them.
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l1 level1 lfo1"><![if !supportLists]><span lang="EN-US"><span style="mso-list:Ignore">1.)<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="EN-US">manually assemble them by adding ‘base images’ to a VM<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l1 level1 lfo1"><![if !supportLists]><span lang="EN-US"><span style="mso-list:Ignore">2.)<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="EN-US">Transform an existing VM automatically.<o:p></o:p></span></p>
<p class="MsoListParagraph"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">If the user wants to modify a template, he need to:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo2"><![if !supportLists]><span lang="EN-US"><span style="mso-list:Ignore">1.)<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="EN-US">clone/copy the VM<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo2"><![if !supportLists]><span lang="EN-US"><span style="mso-list:Ignore">2.)<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="EN-US">start the VM, do any modification, then stop<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo2"><![if !supportLists]><span lang="EN-US"><span style="mso-list:Ignore">3.)<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span lang="EN-US">create a new template from that<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:14.0pt">Other storage types<o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span lang="EN-US"><o:p> </o:p></span></b></p>
<p class="MsoNormal"><span lang="EN-US">This should work with any storage type, because we do not longer<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">depend on internal snapshots.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span lang="EN-US">Directory storage:<o:p></o:p></span></b></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">create base image: <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">mv images/100/vm-100-disk-1.raw images/base/an-arbitray-name.raw<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">create clone: <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">simply create an qcow2 image which refers to the base image<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span lang="EN-US">LVM</span></b><span lang="EN-US">: <o:p>
</o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">create base image:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">simply rename the LV to indicate that it is a template and read only.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">create clone:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">create a snapshot.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Note: I am not really sure if that works on shared storage?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span lang="EN-US">RDB, Sheepdog and others</span></b><span lang="EN-US">:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">create base image:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">do whatever is needed to create a ‘cloneable’ image. This most likely<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">involves to create a ‘snapshot’, and rename/remove the original image.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">create clone:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">storage driver dependent.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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