On Wed, Oct 12, 2016 at 9:59 PM, Giulio Fidente <[email protected]> wrote:
> On 10/12/2016 02:29 PM, Thiago da Silva wrote: > >> >> >> On 10/12/2016 07:10 AM, Giulio Fidente wrote: >> >>> hi, >>> >>> we introduced support for the deployment of Ceph in the liberty >>> release so that it could optionally be used as backend for one or more >>> of Cinder, Glance, Nova and more recently Gnocchi. >>> >>> We used to deploy Ceph MONs on the controller nodes and Ceph OSDs on >>> dedicated ceph-storage nodes so a deployment of OpenStack with Ceph >>> would need at least 1 more additional node to host a Ceph OSD. >>> >>> In our HA scenario the storage backends are configured as follows: >>> >>> Glance -> Swift >>> Nova (ephemeral) -> Local >>> Cinder (persistent) -> LVM (on controllers) >>> Gnocchi -> Swift >>> >>> The downside of the above configuration is that Cinder volumes can not >>> be replicated across the controller nodes and become unavailable if a >>> controller fails, while production environments generally expect >>> persistent storage to be highly available. Cinder volumes instead >>> could even get lost completely in case of a permanent failure of a >>> controller. >>> >>> With the Newton release and the composable roles we can now deploy >>> Ceph OSDs on the compute nodes, removing the requirement we had for an >>> additional node to host a Ceph OSD. >>> >>> I would like to ask for some feedback on the possibility of deploying >>> Ceph by default in the HA scenario and use it as backend for Cinder. >>> >>> Also using Swift as backend for Glance and Gnocchi is enough to cover >>> the availability issue for the data, but it also means we're storing >>> that data on the controller nodes which might or might not be wanted; >>> I don't see a strong reason for defaulting them to Ceph, but it might >>> make more sense when Ceph is available; feedback about this would be >>> appreciated as well. >>> >> I think it would be important to take into account the recently created >> guiding principles [0]: >> >> "While the software that OpenStack produces has well defined and >> documented APIs, the primary output of OpenStack is software, not API >> definitions. We expect people who say they run “OpenStack” to run the >> software produced by and in the community, rather than alternative >> implementations of the API." >> >> In the case of Cinder, I think the situation is a bit muddy as LVM is >> not openstack software, and my limited understanding is that LVM is used >> as a reference implementation, but in the case of Swift, I think RGW >> would be considered an 'alternative implementation of the API'. >> >> Thiago >> > > hi Thiago, > > sorry if it wasn't clear in my original message but I did not suggest to > replace Swift with Ceph RGW. > > Swift would continue to be deployed by default, not RGW. > RGW utilizes Swift. So Swift has to be there anyway -; > > The feedback I'm asking for is about storing (or not) the Cinder volumes > in Ceph for the HA scenario by default, and also store the Glance images > and Gnocchi metrics in Ceph or rather keep that data in Swift. > -- > Giulio Fidente > GPG KEY: 08D733BA > > __________________________________________________________________________ > OpenStack Development Mailing List (not for usage questions) > Unsubscribe: [email protected]?subject:unsubscribe > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > -- Email: [email protected] [email protected]
__________________________________________________________________________ OpenStack Development Mailing List (not for usage questions) Unsubscribe: [email protected]?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
