Thanks for the quick response, but I don't believe I'm there yet ;-)
cloned the glance image to a cinder device
I have configured these three services (nova, glance, cinder) to use
ceph as storage backend, but cinder is not involved in this process
I'm referring to.
Now I wanted to reproduce this scenario to show a colleague, and
couldn't because now I was able to delete image A even with a
non-flattened snapshot! How is that even possible?
Eugen
Zitat von Steve Taylor <steve.taylor@xxxxxxxxxxxxxxxx>:
You're already there. When you booted ONE you cloned the glance
image to a cinder device (A', separate RBD) that was a COW clone of
A. That's why you can't delete A until you flatten SNAP1. A' isn't a
full copy until that flatten is complete, at which point you're able
to delete A.
SNAP2 is a second snapshot on A', and thus A' already has all of the
data it needs from the previous flatten of SNAP1 to allow you to
delete SNAP1. So SNAP2 isn't actually a full extra copy of the data.
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-----Original Message-----
From: ceph-users [mailto:ceph-users-bounces@xxxxxxxxxxxxxx] On
Behalf Of Eugen Block
Sent: Thursday, September 1, 2016 6:51 AM
To: ceph-users@xxxxxxxxxxxxxx
Subject: Turn snapshot of a flattened snapshot into
regular image
Hi all,
I'm trying to understand the idea behind rbd images and their
clones/snapshots. I have tried this scenario:
1. upload image A to glance
2. boot instance ONE from image A
3. make changes to instance ONE (install new package) 4. create
snapshot SNAP1 from ONE 5. delete instance ONE 6. delete image A
deleting image A fails because of existing snapshot SNAP1 7.
flatten snapshot SNAP1 8. delete image A
succeeds
9. launch instance TWO from SNAP1
10. make changes to TWO (install package) 11. create snapshot SNAP2
from TWO 12. delete TWO 13. delete SNAP1
succeeds
This means that the second snapshot has the same (full) size as the
first. Can I manipulate SNAP1 somehow so that snapshots are not
flattened anymore and SNAP2 becomes a cow clone of SNAP1?
I hope my description is not too confusing. The idea behind this
question is, if I have one base image and want to adjust that image
from time to time, I don't want to keep several versions of that
image, I just want one. But this way i would lose the protection
from deleting the base image.
Is there any config option in ceph or Openstack or anything else I
can do to "un-flatten" an image? I would assume that there is some
kind of flag set for that image. Maybe someone can point me to the
right direction.
Thanks,
Eugen
--
Eugen Block voice : +49-40-559 51 75
NDE Netzdesign und -entwicklung AG fax : +49-40-559 51 77
Postfach 61 03 15
D-22423 Hamburg e-mail : eblock@xxxxxx
Vorsitzende des Aufsichtsrates: Angelika Mozdzen
Sitz und Registergericht: Hamburg, HRB 90934
Vorstand: Jens-U. Mozdzen
USt-IdNr. DE 814 013 983
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--
Eugen Block voice : +49-40-559 51 75
NDE Netzdesign und -entwicklung AG fax : +49-40-559 51 77
Postfach 61 03 15
D-22423 Hamburg e-mail : eblock@xxxxxx
Vorsitzende des Aufsichtsrates: Angelika Mozdzen
Sitz und Registergericht: Hamburg, HRB 90934
Vorstand: Jens-U. Mozdzen
USt-IdNr. DE 814 013 983
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