In order to use the RBD mirroring functionality, we will require two Ceph clusters. We could deploy two identical clusters we have been using previously, but the number of VMs involved may exceed the capabilities of what most people's personal machines can run. Therefore, we will modify our vagrant and ansible configuration files to deploy two separate Ceph clusters each with a single monitor and an OSD node.
The required Vagrantfile is very similar to the one used in Chapter 2, Deploying Ceph to deploy your initial test cluster; the hosts part at the top should now look like this:
nodes = [ { :hostname => 'ansible', :ip => '192.168.0.40', :box => 'xenial64' }, { :hostname => 'site1-mon1', :ip => '192.168.0.41', ...
