>>> 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:[email protected]] 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 <[email protected]> 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:[email protected]] >> 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) <[email protected]> >> 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 >> > [email protected] >> > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >> >> _______________________________________________ >> OpenStack-dev mailing list >> [email protected] >> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > > _______________________________________________ > OpenStack-dev mailing list > [email protected] > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev _______________________________________________ OpenStack-dev mailing list [email protected] http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev _______________________________________________ OpenStack-dev mailing list [email protected] http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
