You already deployed successfully Joid and want to scale up ? this is how to add a compute node:
juju add-unit nova-compute
juju status --format=tabular | grep nova-compute
ID=$(juju status --format=tabular | tail -n2 |head -n1 | cut -d\ -f1) juju add-unit ceph-osd --to $ID
juju status --format=tabular | grep ceph-osd
juju set ceph-radosgw ceph-osd-replication-count=2