In the case of a raw backed qcow2 image (pretty sure that¹s the default) the instances root disk as seen inside the vm is made up of changes made on the instance disk (qcow2 layer) + the base image (raw). Also, remember that as currently coded a resize migration will almost always be a migrate. However, since the vm is successfully running on the old compute node it *should* be a trivial change that if the backing image is no longer available via glance - copy that over to the new host as well. ____________________________________________ Kris Lindgren Senior Linux Systems Engineer GoDaddy, LLC.
On 2/5/15, 11:55 AM, "Clint Byrum" <[email protected]> wrote: >Excerpts from George Shuklin's message of 2015-02-05 05:09:51 -0800: >> Hello everyone. >> >> We are updating our public images regularly (to provide them to >> customers in up-to-date state). But there is a problem: If some >>instance >> starts from image it becomes 'used'. That means: >> * That image is used as _base for nova >> * If instance is reverted this image is used to recreate instance's disk >> * If instance is rescued this image is used as rescue base >> * It is redownloaded during resize/migration (on a new compute node) >> > >Some thoughts: > >* All of the operations described should be operating on an image ID. So >the other suggestions of renaming seems the right way to go. "Ubuntu >14.04" becomes "Ubuntu 14.04 02052015" and the ID remains in the system >for a while. If something inside Nova doesn't work with IDs, it seems >like a bug. > >* rebuild, revert, rescue, and resize, are all very _not_ cloud things >that increase the complexity of Nova. Perhaps we should all reconsider >their usefulness and encourage our users to spin up new resources, use >volumes and/or backup/restore methods, and then tear down old instances. > >One way to encourage them is to make it clear that these operations will >only work for X amount of time before old versions images will be removed. >So if you spin up Ubuntu 14.04 today, reverts and resizes and rescues >are only guaranteed to work for 6 months. Then aggressively clean up > >6 month old image ids. To make this practical, you might even require >a role, something like "reverter", "rescuer", "resizer" and only allow >those roles to do these operations, and then before purging images, >notify those users in those roles of instances they won't be able to >resize/rescue/revert anymore. > >It also makes no sense to me why migrating an instance requires its >original image. The instance root disk is all that should matter. > >_______________________________________________ >OpenStack-operators mailing list >[email protected] >http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators _______________________________________________ OpenStack-operators mailing list [email protected] http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators
