We will assume that you have a working Ceph cluster sandbox configured with one or more MON nodes, one or more OSD nodes, and at least one client node. These nodes can be virtual machines if you are running the cluster that we created in Chapter 5, Deploying a Virtual Sandbox Cluster, or they can be physical instances if you already have a cluster running. Most of the actions below will be performed on the client node, but if we need to run a command on an OSD or MON node we'll be sure to note so.
Let's start by logging into the client node and switching to the root user:
$ vagrant ssh client0vagrant@ceph-client0:~$ sudo -iroot@ceph-client0:~#
We can now create a RADOS block device named ceph-client1-rbd1 ...
