在 2014-01-02四的 16:53 +0800，Haomai Wang写道： > On Thu, Jan 2, 2014 at 4:42 PM, Changqian Zuo <dummyhacke...@gmail.com> wrote: > > 在 2014-01-02四的 16:01 +0800，Haomai Wang写道： > >> On Thu, Jan 2, 2014 at 3:38 PM, Changqian Zuo <dummyhacke...@gmail.com> > >> wrote: > >> > Hi, > >> > > >> > First time mailing to a list. > >> > > >> > I'm trying to add a RBD volume snapshot rollback operation to Cinder. > >> > I've just got through WSGI part of Cinder API code and have read some > >> > pieces of Cinder Volume. Now there is not much time for me to complete > >> > the whole code base (with Ceph driver) very carefully, I need some > >> > advice. > >> > > >> > Is adding a Extension Controller the most suitable way to do this? How > >> > to deal with snapshot and volume state transformation, would it affect > >> > other part of Cinder codes? What parts of Cinder codes I should pay > >> > special attention? > >> > > >> > Many thanks. > >> > > >> > Some background information: > >> > > >> > We're planning to use Cinder bootable volume (Ceph RBD as backend) as > >> > instance root disk in my company's OpenStack environment. Creating a > >> > volume snapshot from image, and then use this snapshot to spawn instance > >> > root volumes. > >> > >> From your description, it seemed that you can use rbd as nova backend > >> directly. > >> > >> nova.conf: > >> libvirt_image_type='rbd' > >> > >> more options can be find at nova/virt/libvirt/imagebackend.py > >> > >> > > >> > To backup volume state, I've thought of Cinder-Backup service (still > >> > need to add a in-use backup for Cinder), but it takes too much space (a > >> > 80G volume would take at least 248G space for base backup image with x3 > >> > Ceph replication ratio). The other way is volume snapshot, but in this > >> > case when restoring volume data, I have to create a new volume from > >> > snapshot, destroy the original instance (there's no API to change a > >> > instance's bootable volume), and create a new instance from new volume. > >> > > >> > The old volume can not be removed, for a snapshot is referencing to it > >> > (the snapshot must be kept). If I do this again and again, there would > >> > be many snapshots referencing to many different volumes, and I have to > >> > keep these volumes (not used elsewhere), which is a mess. > >> > > >> > > >> > > >> > _______________________________________________ > >> > Mailing list: > >> > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack > >> > Post to : openstack@lists.openstack.org > >> > Unsubscribe : > >> > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack > >> > >> > >> > > Thanks, > > > > I do know in Havana release, we could use RBD as Nova image storage. > > There are reasons I choose such a way to launch an instance. Firstly, > > our company are moving from XCP to OpenStack, we have an old framework > > and business mode to manage Xen instance and VDIs, so hoping to fit > > OpenStack into this framework. The decision is made by my boss. > > Secondly, I myself would prefer this way, for it would be to easy to > > manage root disk, for example, I could use Cinder Backup service to do > > some remote backup. Using nova image, the root disk may not be easily > > seen. > > Do you mean store all the images at Cinder too and clone bootable volume when > booting instance? Why need rollback? > > I'm afraid that you can't get enough benefits from "booting from volume". > There > exists many limits on this way. Such as injecting data failed, chaotic > snapshot > management and others. > > > > > > > > >
Yes, we don't use ephemeral disk. We don't take instance snapshot, instead, just take a volume snapshot (instance's root disk or data volume, Yea, instance memory would be lost). Thanks for the bug information. _______________________________________________ Mailing list: http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack Post to : openstack@lists.openstack.org Unsubscribe : http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack
