Hi, I am currently looking for a open source solution that is able to expose a single API endpoint for a user to multiple Openstack instances. Partly the idea behind is to stop investing efforts into tuning of Openstack to make it scalable and instead to deploy a bunch of small Openstack regions (say ~100 nodes) and work with them via API frontend. I am aware of Nova Cells, but it is complicated and Nova is not the only Openstack component that needs scaling. All these ad hoc tuning like dedicated RabbitMQ instances just make the system barely maintainable and it is complicated to reproduce. Requirements for a possible solution are: - Single authentication point (I know this is simple and can be for example SAML based federation) - Single point to manage keys and quotas - Possibly L2 connectivity between VMs in different Openstack instances (I know this can be achieved using VPNs, but this is kinda too complicated for a user) - Ability to work with different Openstack versions (need for gradual upgrade) I know Huawei and others implemented PoC for Openstack cascading and then invested some efforts in Trio2o and Tricircle. Tricircle is about cascading Neutron and IMO it is better to use a scalable SDN (like TangstenFabric or OVN). Trio2o looks like what I actually need, but the community interest around Trio2o is very limited (frankly, it looks almost dead). Last few weeks I was experimenting with Trio2o and Devstack with Stein release. It looks working, but the functionality is limited. Is there anyone who is interested in reviving Trio2o and investing into it? Maybe there are other solutions that I am not aware of? -- Best regards, Kozhukalov Vladimir