# Ceph RBD Mirroring and OpenNebula **URL:** \ **Category:** Operations\ **Created:** [April 8, 2020, 9:24am UTC](https://forum.opennebula.io/t/ceph-rbd-mirroring-and-opennebula/8308 "2020-04-08T09:24:19Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![MedicMomcilo](https://yyz1.discourse-cdn.com/flex031/user_avatar/forum.opennebula.io/medicmomcilo/32/5678_2.png) [@MedicMomcilo](https://forum.opennebula.io/u/MedicMomcilo)\ **Post date:** [April 8, 2020, 9:24am UTC](https://forum.opennebula.io/t/ceph-rbd-mirroring-and-opennebula/8308/1 "2020-04-08T09:24:20Z")
Hi friends! In the process of setting up secondary Ceph cluster we are exploring our options for ONE VM failovers. For this, we would like to set up RBD mirroring and have a disaster recovery scenario ready (in case primary Ceph cluster becomes unreachable). As far as I could find out, OpenNebula doesn’t immediatelly supports any form of Ceph RDB Mirroring utilization. To make things more difficult, ONE heavily relies on naming convention and we can never have two VMs that use image with same underlaying name. E.g. VM with ID 1337 would be the only one using Ceph image “pool/one-100-1337-0” and we can’t have different VM defined with that image. As Ceph doesn’t support RBD mirroring to a different name (e.g. pool/image-a =\> pool/image-b), this looks like a show stopper… Is there any recommendation as to how to approach this problem? Our current thinking involves a lot of low-level tinkering and raw libvirt manipulation to boot VMs off main site. Kind regards, Momo. ---
**Author:** ![atodorov\_storpool](https://yyz1.discourse-cdn.com/flex031/user_avatar/forum.opennebula.io/atodorov_storpool/32/5327_2.png) [@atodorov\_storpool](https://forum.opennebula.io/u/atodorov_storpool)\ **Post date:** [April 9, 2020, 8:40am UTC](https://forum.opennebula.io/t/ceph-rbd-mirroring-and-opennebula/8308/2 "2020-04-09T08:40:42Z")
Hi Momo, I am not a Ceph expert so please read the following as a shared thoughts instead of specific recommendation/solution. First to clarify the base setup: A. An OpenNebula controller with Mysql/MariaDB A. Two separate CEPH clusters with RBD mirroring B. Two separate set of Hypervisors D. The network routing is setup/resolved in a way that both sites could export/route VM’s IPs Following the Ceph’s definition let name the current OpenNebula setup _primary_ and the DR one _remote_ What do you think of creating a frontend node on the _remote_ site that has no running OpenNebula services, only the database is replicated with the _primary_ site and all credentials are same. The hosts from the _remote_ site are defined in the _primary_ OpenNeubla but in _Disabled_ state. The _remote site_ is configured to work with the _remote_ ceph where the images are mirrored(same pools, same names… only with different credentials). So in case of DR - (assuming the entire primary site is down) you need to reconfigure the _remote_ frontend: set the database as master, start the OpenNebula services, disable the _primary_ hosts and enable _remote_ hosts. My assumption is, that if the remote hosts are configured as twins of the _primary_ ones same bridge names, etc. The OpenNebula will behave like it is run on the “primary” site. Same database, same credentials, same VNets, and same Images for same VMs. This way you could just start the VMs on the _remote_ site… I’d think in this direction to resolve a DR case. Please excuse me if I omit something obvious issues but unknown to me… Best Regards, Anton Todorov ---
**Author:** ![MedicMomcilo](https://yyz1.discourse-cdn.com/flex031/user_avatar/forum.opennebula.io/medicmomcilo/32/5678_2.png) [@MedicMomcilo](https://forum.opennebula.io/u/MedicMomcilo)\ **Post date:** [April 9, 2020, 8:54am UTC](https://forum.opennebula.io/t/ceph-rbd-mirroring-and-opennebula/8308/3 "2020-04-09T08:54:57Z")
Hi Anton, Thank you so much for sharing your idea. It looks very promising at a first glance. I’ll discuss internally and provide more info as it comes by. Again, thank you, highly appreciated 🙂 Kind regards, Momo.