Is there a way we can use EBS for ec2 instance with juju. And possibility of scaling the storage after the deployment,
I think this the thing you looking for. Just look at it. http://ceph.com/dev-notes/deploying-ceph-with-juju/ and link below also you will need after Ceph charm deployment. http://www.webmastersessions.com/how-to-attach-ebs-volume-to-amazon-ec2-instance
P.s. no hard feelings just trying to help.