On Tue, Mar 4, 2014 at 1:06 AM, Qin Zhao <chaoc...@gmail.com> wrote: > I think the current snapshot implementation can be a solution sometimes, but > it is NOT exact same as user's expectation. For example, a new blueprint is > created last week, > https://blueprints.launchpad.net/nova/+spec/driver-specific-snapshot, which > seems a little similar with this discussion. I feel the user is requesting > Nova to create in-place snapshot (not a new image), in order to revert the > instance to a certain state. This capability should be very useful when > testing new software or system settings. It seems a short-term temporary > snapshot associated with a running instance for Nova. Creating a new > instance is not that convenient, and may be not feasible for the user, > especially if he or she is using public cloud. >
Why isn't it easy to create a new instance from a snapshot? > > On Tue, Mar 4, 2014 at 1:32 PM, Nandavar, Divakar Padiyar > <divakar.padiyar-nanda...@hp.com> wrote: >> >> >>> Why reboot an instance? What is wrong with deleting it and create a >> >>> new one? >> >> You generally use non-persistent disk mode when you are testing new >> software or experimenting with settings. If something goes wrong just >> reboot and you are back to clean state and start over again. I feel it's >> convenient to handle this with just a reboot rather than recreating the >> instance. >> >> Thanks, >> Divakar >> >> -----Original Message----- >> From: Joe Gordon [mailto:joe.gord...@gmail.com] >> Sent: Tuesday, March 04, 2014 10:41 AM >> To: OpenStack Development Mailing List (not for usage questions) >> Subject: Re: [openstack-dev] [nova][cinder] non-persistent storage(after >> stopping VM, data will be rollback automatically), do you think we shoud >> introduce this feature? >> Importance: High >> >> On Mon, Mar 3, 2014 at 8:13 PM, Zhangleiqiang <zhangleiqi...@huawei.com> >> wrote: >> >> >> >> This sounds like ephemeral storage plus snapshots. You build a base >> >> image, snapshot it then boot from the snapshot. >> > >> > >> > Non-persistent storage/disk is useful for sandbox-like environment, and >> > this feature has already exists in VMWare ESX from version 4.1. The >> > implementation of ESX is the same as what you said, boot from snapshot of >> > the disk/volume, but it will also *automatically* delete the transient >> > snapshot after the instance reboots or shutdowns. I think the whole >> > procedure may be controlled by OpenStack other than user's manual >> > operations. >> >> Why reboot an instance? What is wrong with deleting it and create a new >> one? >> >> > >> > As far as I know, libvirt already defines the corresponding <transient> >> > element in domain xml for non-persistent disk ( [1] ), but it cannot >> > specify >> > the location of the transient snapshot. Although qemu-kvm has provided >> > support for this feature by the "-snapshot" command argument, which will >> > create the transient snapshot under /tmp directory, the qemu driver of >> > libvirt don't support <transient> element currently. >> > >> > I think the steps of creating and deleting transient snapshot may be >> > better to done by Nova/Cinder other than waiting for the <transient> >> > support >> > added to libvirt, as the location of transient snapshot should specified by >> > Nova. >> > >> > >> > [1] http://libvirt.org/formatdomain.html#elementsDisks >> > ---------- >> > zhangleiqiang >> > >> > Best Regards >> > >> > >> >> -----Original Message----- >> >> From: Joe Gordon [mailto:joe.gord...@gmail.com] >> >> Sent: Tuesday, March 04, 2014 11:26 AM >> >> To: OpenStack Development Mailing List (not for usage questions) >> >> Cc: Luohao (brian) >> >> Subject: Re: [openstack-dev] [nova][cinder] non-persistent >> >> storage(after stopping VM, data will be rollback automatically), do >> >> you think we shoud introduce this feature? >> >> >> >> On Mon, Mar 3, 2014 at 6:00 PM, Yuzhou (C) <vitas.yuz...@huawei.com> >> >> wrote: >> >> > Hi stackers, >> >> > >> >> > As far as I know ,there are two types of storage used by VM in >> >> > openstack: >> >> Ephemeral Storage and Persistent Storage. >> >> > Data on ephemeral storage ceases to exist when the instance it is >> >> > associated >> >> with is terminated. Rebooting the VM or restarting the host server, >> >> however, will not destroy ephemeral data. >> >> > Persistent storage means that the storage resource outlives any >> >> > other >> >> resource and is always available, regardless of the state of a running >> >> instance. >> >> > >> >> > There is a use case that maybe need a new type of storage, maybe we >> >> > can >> >> call it non-persistent storage . >> >> > The use case is that VMs are assigned to the public ephemerally in >> >> > public >> >> areas. >> >> > After the VM is used, new data on storage of VM ceases to exist >> >> > when the >> >> instance it is associated with is stopped. >> >> > It means stop the VM, Non-persistent storage used by VM will be >> >> > rollback >> >> automatically. >> >> > >> >> > Is there any other suggestions? Or any BPs about this use case? >> >> > >> >> >> >> This sounds like ephemeral storage plus snapshots. You build a base >> >> image, snapshot it then boot from the snapshot. >> >> >> >> > Thanks! >> >> > >> >> > Zhou Yu >> >> > >> >> > _______________________________________________ >> >> > OpenStack-dev mailing list >> >> > OpenStack-dev@lists.openstack.org >> >> > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >> >> >> >> _______________________________________________ >> >> OpenStack-dev mailing list >> >> OpenStack-dev@lists.openstack.org >> >> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >> > >> > _______________________________________________ >> > OpenStack-dev mailing list >> > OpenStack-dev@lists.openstack.org >> > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >> >> _______________________________________________ >> OpenStack-dev mailing list >> OpenStack-dev@lists.openstack.org >> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >> >> _______________________________________________ >> OpenStack-dev mailing list >> OpenStack-dev@lists.openstack.org >> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > > > > > -- > Qin Zhao > > _______________________________________________ > OpenStack-dev mailing list > OpenStack-dev@lists.openstack.org > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > _______________________________________________ OpenStack-dev mailing list OpenStack-dev@lists.openstack.org http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev