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Re: KVM NFS template image


Looks like a bug (missing processing case).

чт, 22 нояб. 2018 г., 15:54 Andrija Panic andrija.panic@xxxxxxxxx:

> Hi Run,
>
> not sure what you mean  (I did not quite understand your explanation) - but
> here is an exercise from my side (just done it):
>
> https://pasteboard.co/HOowNao.png
>
> Check the image - explanation below:
>
>
> Centos55 minimal (builtin) template, spin new VM:
> --- new volume created with UUID/PATH (name on NFS files
> system): 021e8602-235b-4e0d-b9e4-04f0ff46399f
> --it's backing file: backing file:
>
> /mnt/63a3ae7b-9ea9-3884-a772-1ea939ef6ec3/93682641-e7f6-11e8-8f64-089e01d943be
>
> Create snapshots via GUI - there is qcow2 snapshots created, whole snapshot
> copied over (converted via qemu-img - "ps aux | grep qemu-img") tool to
> Secondary NFS Storage - and snapshot REMOVED from original volume on
> Primary NFS Storage (qemu-img snapshot -l
> 021e8602-235b-4e0d-b9e4-04f0ff46399f shows zero snaps after ACS has
> finished creating snapshots)
> Volume still points to it's backing file - no changes so far (as expected)
>
> Then I restore volume from snapshots.
> CloudStack will (my conclusions from the exercise), remove original volume
> on NFS Primary Storage (021e8602-235b-4e0d-b9e4-04f0ff46399f), then it will
> copy back (convert via qemu-img) a qcow2 file from Secondary Storage back
> to Primary Storage - but it will use SAME NAME, so you again see
> 021e8602-235b-4e0d-b9e4-04f0ff46399f on your NFS mount point.
>
> This time when you check the image with qemu-img info - it will show it has
> NO backing file at all - since it's brand new volume/qcow2 image created
> (as a copy fom Secondary Storage)
>
> that is how it works
>
> I assume the template will be again cleaned-up/removed from Primary Storage
> if no other VMs/volume use it as it's backing (parent) image.
>
> Makes sense ?
>
> Cheers
>
> On Thu, 22 Nov 2018 at 21:18, ran huang <ran.huang134@xxxxxxxxx> wrote:
>
> > Thanks Andrija, just tested myself with expunge and works as expected.
> >
> > However, for KVM, when I revert a qcow disk from snapshot, which removes
> > the backing chain to template, the template will not be removed.
> >
> > So it seems like despite the qcow disk is no longer backed by the
> > template, the template will still consider the disk as its children in
> > this case(revert from snapshot).
> >
> > regards,
> > Ran
> >
> > On 11/19/2018 10:43 AM, Andrija Panic wrote:
> > > new template, deployed new VM, destroyed VM (with Exunge option)...
> > >
> > > up to 120sec later... (storage.cleanup.interval=120 sec,  global config
> > > option)
> > >
> > > 2018-11-19 19:35:59,525 DEBUGStorage pool garbage collector found 1
> > > templates to clean up in storage pool: Primary-storage - NFS
> > > 2018-11-19 19:35:59,525 DEBUG [c.c.s.StorageManagerImpl]
> > > (StorageManager-Scavenger-1:ctx-2c88c8e0) (logid:040f4ad1) Storage pool
> > > garbage collector has marked template with ID: 219 on pool 4 for
> garbage
> > > collection
> > >
> > > Another  120sec later... (storage.cleanup.delay=120sec)
> > >
> > > 2018-11-19 19:37:59,598 DEBUG [c.c.s.StorageManagerImpl]
> > > (StorageManager-Scavenger-2:ctx-f9dd338d) (logid:9ae40975) Storage pool
> > > garbage collector found 1 templates to clean up in storage pool:
> > > Primary-storage - NFS
> > > ...
> > > 2018-11-19 19:37:59,638 DEBUG [c.c.t.TemplateManagerImpl]
> > > (StorageManager-Scavenger-2:ctx-f9dd338d) (logid:9ae40975) Evicting
> > > TmplPool[37-219-4-563ea0f5-5164-4ac4-a183-728f418269b7]
> > > 2018-11-19 19:37:59,643 DEBUG [c.c.h.o.r.Ovm3HypervisorGuru]
> > > (StorageManager-Scavenger-2:ctx-f9dd338d) (logid:9ae40975)
> > > getCommandHostDelegation: class
> > com.cloud.agent.api.storage.DestroyCommand
> > > ...
> > > 2018-11-19 19:37:59,665 DEBUG [c.c.t.TemplateManagerImpl]
> > > (StorageManager-Scavenger-2:ctx-f9dd338d) (logid:9ae40975) Successfully
> > > evicted template andrija-test-tmpl from storage pool null
> > >
> > > template "andrija-test-tmpl" deleted...
> > >
> > > Hope that helps Run.
> > >
> > > Cheers
> > > Andrija
> > >
> > > On Mon, 19 Nov 2018 at 19:11, Andrija Panic <andrija.panic@xxxxxxxxx>
> > wrote:
> > >
> > >> True (at least I'm sure for SolidFire) - but I believe in general also
> > >> (will test this now...)
> > >>
> > >> On Mon, 19 Nov 2018 at 18:51, Dag Sonstebo <
> Dag.Sonstebo@xxxxxxxxxxxxx>
> > >> wrote:
> > >>
> > >>> Developers please correct me... but as far as I remember there is a
> > >>> garbage collector which does remove the templates from primary
> storage
> > once
> > >>> they are not needed (i.e. have no more "child VMs"). This is
> > controlled by
> > >>> the global setting "storage.template.cleanup.enabled".
> > >>>
> > >>> Regards,
> > >>> Dag Sonstebo
> > >>> Cloud Architect
> > >>> ShapeBlue
> > >>>
> > >>>
> > >>> On 16/11/2018, 22:51, "ran huang" <ran.huang134@xxxxxxxxx> wrote:
> > >>>
> > >>>      Hi Andrija,
> > >>>
> > >>>      Thanks for the clarification and quick response
> > >>>
> > >>>      regards,
> > >>>      Ran
> > >>>
> > >>>      On 11/16/2018 02:15 PM, Andrija Panic wrote:
> > >>>      > Hi Ran,
> > >>>      >
> > >>>      > templates stays on Primary Storage "forever", at least for NFS
> > >>> (they are
> > >>>      > moved from Secondary to Primary when you deploy a very first
> VM
> > from
> > >>>      > specific template). All VMs have this templates qcow2 as
> baking
> > >>> (parent)
> > >>>      > image.
> > >>>      >
> > >>>      > This template is a qcow2 copy of a file from Secondary
> Storage -
> > >>> and is
> > >>>      > considered a "parent" image, from which all child images  (VM
> > >>> volumes) are
> > >>>      > created - as you stated baking file (qcow linked clones, in
> > official
> > >>>      > terminology)
> > >>>      >
> > >>>      > you can have i.e. 100 VMs all linking (having it's backing
> > file...)
> > >>> to a
> > >>>      > template qcow2 file.
> > >>>      > So in other words, it's not supposed to be removed.
> > >>>      >
> > >>>      > Does this make sense?
> > >>>      >
> > >>>      > Cheers
> > >>>      >
> > >>>      >
> > >>>      >
> > >>>
> > >>> Dag.Sonstebo@xxxxxxxxxxxxx
> > >>> www.shapeblue.com
> > >>> Amadeus House, Floral Street, London  WC2E 9DPUK
> > >>> @shapeblue
> > >>>
> > >>>
> > >>>
> > >>>> On Fri, 16 Nov 2018 at 22:38, ran huang <ran.huang134@xxxxxxxxx>
> > wrote:
> > >>>      >
> > >>>      >> Greetings All,
> > >>>      >>
> > >>>      >> For qcow2 format images, when creating a new VM in KVM, the
> > >>> template
> > >>>      >> image is copied from secondary storage to primary storage,
> and
> > the
> > >>> root
> > >>>      >> volume image is created with the template image as a backing
> > file.
> > >>>      >>
> > >>>      >> But when I break this backing chain on primary(expunge VM or
> > >>> revert to a
> > >>>      >> snapshot previously created on the root volume image), the
> > template
> > >>>      >> image is not deleted.
> > >>>      >>
> > >>>      >> Might I ask how is the template image going to be cleaned
> from
> > the
> > >>>      >> primary storage?
> > >>>      >>
> > >>>      >>
> > >>>      >> addendum:
> > >>>      >> CS ver 4.9.2 on CentOS 7.2
> > >>>      >>
> > >>>      >> regards,
> > >>>      >> Ran
> > >>>      >>
> > >>>      >
> > >>>
> > >>>
> > >>>
> > >>>
> > >> --
> > >>
> > >> Andrija Panić
> > >>
> > >
> >
> >
>
> --
>
> Andrija Panić
>